Duke in Australia 2014

As a follow up to our summer’s class, a group of us visited the Duke Lemur Center on Friday 26 September.  Our excellent guide talked about Madagascar biogeography, and then showed us some of the excellent lemurs at the center.

Please click below to open my paper.

Parrot Paper

A kookaburra in a gum tree!

“Kookaburra sits in the old gum tree; Merry, merry king of the bush is he; Laugh, Kookaburra! Laugh, Kookaburra! What a life you lead…” This popular Australian nursery rhyme exemplifies the distinguished place that Kookaburras hold within Australian culture. From this song, the average American might think that Kookaburras only inhabit Australia; however, there are actually four species of living Kookaburras and only two are found within the Australian coasts. The two species commonly known as the Laughing and Blue-winged Kookaburras are endemic to Australia, while the other two, the Spangled and Rufous-Bellied Kookaburras, can be found in the Aru Islands, Indonesia, New Guinea, Papuan Islands, Irian Java, and the Islands of Geelvink (Forshaw). Kookaburras are not unique to Australia. The kookaburras belong to the Kingfisher clade, which is a group of birds that exists all throughout the world (minus oceanic islands and polar regions) (Scott).There are various similarities and distinctions between the evolutionary history and ecology of kookaburras and their sister kingfishers that inevitably led to the existence of separate species.

The name “kingfisher” refers to the birds’ royal blue and imperial purple plumage and their diet of fish, although not all prey on aquatic animals. The commonalities that exist between all kingfishers include their long, heavy bills, large heads, thickset bodies, short legs, specific feet, short wings, and feathery crests (Strahan). Their feet are one of the main differentiating factors from other birds; their talon formation is an exclusive characteristic of the kingfisher clade! More specifically, their second and third toes are joined at the base, the third and fourth are united for most of their length, and their first toe points backwards while perching (Scott). Also due to the built of their bodies, kingfishers cannot walk on the ground. Instead they need to hop from place to place! One might think this is a hindrance on their predation abilities, however their binocular vision combined with their fast flying enables them to catch plenty of prey. Once one of these mighty birds spies an animal of prey from his/her perch, they swiftly swoop down, either into the water or close to the ground, to successfully claim their food (Strahan). All things considered, the structure of the bill and the feet are the most discernible features of a bird in the kingfisher clade (Forshaw).

Phylogeny

The phylogenetic tree of the Kingfisher clade.

A common kingfisher.

The kingfisher clade is a monophyletic group which implies that this group of organisms are derived from a common ancestor. The Kingfisher clade also has the Linnaean biological classification as being the Alcedinidae family, stemming from the Coraciiformes order.  This family is divided into subfamies, genera, and species. Since the division lines are not clearly defined by current or past scientists for the different Linnaean taxonomic groups, there is often disagreement and inconsistency between different sources. Some believe that there should be three distinct subfamilies, while others only use two. The recent sources of the 21^st century sources agree that there should be three subfamilies: Alcedininae (river kingfishers), Halcyoninae – also known as Daceloninae from earlier authors (tree/forest kingfishers), and Cerylinae (water kingfishers) (Christidis). According to the authors of “Systematics and Taxonomy of Australian Birds” these three subfamilies were determined by DNA-DNA hybridization, chromosomes, myology, moult patterns, and mitochondrial and nuclear DNA sequences. Those who fight for only two subgroups leave out the Cerylinae classification and just have the tree kingfishers and one group for the kingfishers that are found in water habitats (Scott). The actual number subfamilies is not important, but instead one should pay attention to the differences between the tree and water kingfishers. The tree kingfishers are physically distinct by their wide, flat bills that occasionally have a hooked tip, while the water kingfishers are known to have slender, sharp pointed bills. (The hooked bills are hypothesized to be an adaptation useful for digging in the ground (Forshaw).) Another key difference is their nesting locations. Tree kingfishers habitually nest in tree-holes, whereas water kingfishers tend to build their nests in burros (Strahan). Kookaburras are part of the tree kingfishers, also known as either Halcyoninae or Dacelonina.  After the separation of these birds into tree and water kingfishers, the groups are divided into more specific clusters called genera.

The subfamily of the Halcyoninae contains four genera, one of which is Dacelo. Dacelo is the genus that contains the two Australian kookas (Christidis). The Dacelo genus is soley composed of the four kookaburra species. The two Australian species are Dacelo leachii, the blue-winged kookaburra, and Dacelo novaeguineae, the laughing kookaburra (the old Latin name was Dacelo gigas). The laughing kookaburra also contains a subspecies, Dacelo novaeguineae minor (Strahan). Some characteristics are universal to all kookaburras including their social system, the size and function of their territory, their vocal behavior, their visual behavior, the growth of their young, and their moratlity and predation patterns. These universal characteristics shared by the Dacelo genus will be further elaborated on in the following paragraphs.

Characteristics of the genus Dacelo

A family of kookas! A mated pair with an auxiliary.

To begin to describe these wondrous living organisms, kookaburras actively take part in a social system that is not common to many birds or animals.Typically a similar social dynamic is seen amongst primate and human populations. Yes, some birds like the pied-butcher bird, have a comparable social system, but when Veronica Parry (a scientist who devoted her life to the studying of kookaburras) first witnessed their dynamic she was flabbergasted. To understand their social dynamic, one should know that kookaburras are quite territorial. Once mated, (Kookaburras mate for life, unless their mate dies. If so they might find another mate in order to sustain their fitness as a species and continue to pass on their genes.) they occupy the same territory year round; within this territory exists a “family” of kookas. Kookaburras tend to congregate and live with 3 or more individuals. These families consist of a mated pair plus their auxiliaries. As defined by Parry, an auxiliary is an “adult non-breeding birds which instead of dispersing and breeding themselves, remain within their parents’ territory year round and aid in the territory defense, incubation of eggs, feeding and protecting of young”. Basically, auxiliaries actively take part in the nesting duties as if they were the actual parents. They incubate the eggs before they hatch and then after they hatch they take part in feeding and protecting the chicks and fledgings until they can survive on their own. These auxiliaries tend to continue to help their parents for up to three years even though they are sexually mature after one year and technically can mate and reproduce. It is believed by Parry and other scientists that auxiliaries do not leave their territory once sexually mature due to the fact that their urge to breed is suppressed by their subordinate position within their family.  Families have two separate hierarchies, one for the females and one for the males. The breeding pair is considered to be dominant within their respective hierarchy and is therefore challenged by those below him/her. Although kookas generally coexist in peace, the dominance is settled through sparring matches. A sparring match entails two birds to grasp each other’s bills and twist and turn for thirty seconds to fifteen minutes. If one of the two birds is thrown off his/her perch or simply flies away, the match is over. This social dynamic of having a “family” in which the matured offsprings take equal part with their parents in raising their brothers and sisters (well not in the actual conception part) is not widely seen within the bird species.

As mentioned earlier, kookaburras lay claim to permanent sets of territory. Since Australia’s climate is quite mild, birds tend not to migrate and therefore these permanently settled kookas get to know their personal hunting grounds quite well. Food resources, the existence of at least one hole large enough to nest in, a grounded clearing to frequent for food, some area of dense tree cover to be used as a roosting site or, later on, a refugee site for fledgings, and an area that is consistent with the amount of space a kooka can efficiently defend are all factors that limit the size of a kookaburra’s territory. After all thse factors are taken into an account, an average adult kooka will have approximately three acres of land. If a family’s territory is dependent on the number of individuals within that family. So, a family of three will span over 18 acres of land. Since an auxiliary is an adult kooka, they also account for a portion of the family’s territory. Each auxiliary accounts for 3 acres of a family’s territory therefore creating a ceiling on the number of mated pairs that can breed in a set-sized territory.  Auxiliaries are seen as “acting through sociality as a method of birth control” because they limit the amount of breeding territory in an ecosystem. Once a mated kooka pair and its family has established a set territory, they vigilantly guard their borders against intruders who attempt to encroach on their land; this is an aspect of kookaburra’s visual behavior.

A kookaburra demonstrating “stick pose” to avoid the eyes of their predators.

Besides specific territory defense behavioral patterns, kookaburras also exhibit particular fear, camouflage, roosting, feeding, and courtship behaviors. When a kooka is caught in a near death situation, he/she will do its best to appear as menacing as possible. First he/she will become absolutely motionless. Then he/she will simultaneously open his/her bill to its full extent and raise his/her short crest feathers to give the head a peculiar shape. This is a kooka’s last resort for saving its life in the face of danger! Another common technique for avoiding being eaten is camouflage. When a flying predator, like a wedge-tailed eagle, is a round the kookas like to assume ‘stick pose’ to help them blend in with their surroundings. To assume the ‘stick pose’, the kooka stops all activity and points its bill skyward. Then using their keen eyes, the kookas follow the passage of the bird of prey with their entire body. Since the kooka is coated with brown plumage along its head and back and moves as a solid unit, to the hungry eyes above they appear as sticks! Hench the name ‘stick pose’. Another defense mechanism for staying alive has to do with their sleeping habits. At night while they sleep (kookas are diurnal), they bunch up together so that they look like one long line of feathers. This is tactic is used to disguise their exact size from nocturnal creatures, like the powerful owl, that may be lurking around while they rest. Kookaburras stick to two or three regular roosting trees for sleeping; these are the same tree that they use to perform their evening chorus. All in all, when these birds are not hiding from those animals that eat them, they are often hunting for their own food.

A kooka eating a lizard, yum! Watch this link to see how their neck muscle help them kill their prey: https://www.youtube.com/watch?v=WYKOv53jUUs

Kookas also have some mischievous methods to alluding and capturing their own prey (Cheeky little birds!). Worms, snails, snakes, insects, freshwater crayfish frogs, lizards, snakes and occasionally small birds and rodents generally compose the diet of these insectivores/carnivores.  In order to catch their prey, kookaburras first make use their keen eyesight while perching in a tree to spot their next meal. Once an edible creature is discovered, the kooka uses its strong neck muscles (Adapted from their kingfisher ancestors who would dive into water for food) to kill their prey. The neck muscles are used to bash the victim against a hard surface until death. Once dead, the bird tosses back its head and swallows the food within a jerk or two. Anything indigestible is brought back up in the form of a food pellet (yum)! (Parry) Eating is necessary task for survival, especially when the mother kooka needs to form eggs. In order to remain alive and reproducing in the wild, the kookaburras have adopted these advantageous behavioral patterns.

Another important behavior to remain reproductively fit is the actual act of courting another kookaburra. There are two main steps before the final step of courtship, copulation, is achieved: courtship feeding and the nest-showing ceremony. Courtship feeding begins as much as 44 days before egg-laying and could continue up to 6 days after. This feeding period consists of the male kooka passing food to his egg-laying mate in order to ensure that she is nutritionally stable to properly form durable eggs. The male typically ends up gathering more food for his mate rather than for himself during this time period. Since the kookaburras attempt to plan the hatching of their eggs in conjunction with the peak of the food season,  there is no guarantee how abundant food will be in the days leading up to the egg-laying date which validates the usefulness of courtship feeding. While courtship feeding is occurring, the mated pair also begins the nest-showing ceremony. This ceremony begins about 40 days before egg laying and is a ritual for choosing a  nesting location for the mates’ eggs. The kookaburras either visit their old nest from the year before (as long as no bees or possums have taken over it) or look for a new hole! Once they agree on a hole, they visit the nest together every day in order to make it ready for egg laying. This part of the courting is accompanied by ‘soft squawk’ calls which give comfort to the life-long partners. The nest-showing ceremony ends four days before egg laying; although it is common for the kookas to return to the nest alone during this four day period to simply perch outside of it. There is no special ceremony for the actual copulation, but the act does tend to occur close to the nest!

This is a typical tree hole used as a nest by the kookaburras.

A termite mound is another nest option for kookaburras.

Sparring kookaburras! To see a fight in action watch this video : https://www.youtube.com/watch?v=_XvcDwIvNy8

Another well-known behavioral characteristic of these birds is their defensive nature. There is a variety of ways to accomplish in which kookaburras defend their territory: a trapeze display, a circle flight, or a physical attack. The most common of the three is also the least hostile, a trapeze act. One can guess from the name what this behavior is similar to: a circus performance! This defense mechanisms occurs at the boundary of a family’s territory. Opposing families gather on either side of the boundary and one bird from each family begins to fly to and fro, from perch to perch, while passing the other in midair. Neither family ever crosses the territory boundary and the performance ends when the invaders fly away. Circle flights, on the other hand, are slightly more hostile way to defend territory. Circle flight are most often seen during the months June to September (this is the time period when families are in search of more territory for mating which begins around September). A circle flight is triggered by seeing an intruder within the territory boundaries. The territory owner then proceeds to burst into song and jump into a high-speed flight pursuit (aka fast and furious in the bird world) until the intruder is no longer within the boundaries. If the intruder decides to stand his ground, and not leave, then the bird’s most hostile form of defense is used: a physical attack. This attack begins with the bird emitting a low chuckle and is followed by the up and down pumping of its tail and ultimately ends with an assault of the offender. (Funny aside: These physical attacks are the reason why kookaburras crash into glass doors! They are not aware that glass can reflect images. So when they see themselves in the reflection of the glass door, they often forcefully attack the glass leading to a broken door and injured kookas.) Defending ones territory is a family activity that all kookaburras take part in. This activity not only aids in keeping the chicks and fledgings safe, but it also helps form stronger bonds within the family.

Frequncy of calls during a general year!

Before one can see a kooka, they often hear them. Kooaburras are known for their boisterous, some might say obnoxious, songs. Kookaburras communicate using six different calls and one song which are unique to each species. As defined by Parry, the difference between songs and calls are as follows: a song is the “most characteristic vocalization of the species”, while a call is “socially serviceable within the species concerned for they communicate”. Certain vocal sounds are used more often than other depending on the time of the year. For example, as mentioned before, the ‘soft squawk’ is more frequent during the breeding months. The six characteristic calls that are used between families include the chuckle, chuck, squawk, soft squawk, cackle, and kooaa. Each call has its own meaning. The chuckle locates family members year round. When one abbreviates a chuckle, they get a chuck! A chuck is often connected with feeding fledgings and chicks. Also it is used to locate family members during the breeding season. Next is a squawk which is a food begging and submissive call to reduce aggression among family members during the breeding season. Also used during the breeding season, but for a completely different reason is a soft squawk. This type of squawk is a courtship call of the mated pair, specifically to reduce the breeding female’s aggression. Oppositely, a signal of aggression is a cackle. Cackles are considered a war cry which occurs before an attack. Last but not least, a kooaa is a warning device heard year round which draws attention of the group. These calls all are only used within families to communicate. The more defining characteristic of different families is their song. Songs are sung at least twice a day, once at dawn and once at dusk in the roosting site. Singing is found to be a group activity for kookas; family members sing together to either maintain their pair bond (mates) or cement the social family bond. Also the singing of these songs is quite revered. Two families will not sing at the same time, they will wait for the other to finish. Also demonstrating their importance is the fact that the songs are known to stop fights. If two birds are sparring and they hear a neighboring family’s song they will instantly pause their fight for the duration of the song and then pick back up again after it finishes. During the breeding months, less kooka songs are heard because normally one of the mates incubating the eggs and the mates wont singing a dusk/dawn song if they are apart. Conversely during the three months before breeding season (around June to September), one will hear more of the kookas songs because this is the time of the year when territorial boundaries are challenged. Kookaburras’ songs are used to advertise ownership of their territory too (Parry). These iconic songs are an identifying aspect of the kookaburra and contain considerable meaning in their everyday life.

As with most animals, death takes its highest toll in the first year of a kookaburra’s life. The main cause of kookaburra death comes from predation. For example, brushed-tailed phascogale (a carnivorous rat-sized marsupial that lives in hollow branches) licks the contents of the kooka’s eggs and enjoys preying on young nestlings. Cats and foxes tend to be the main cause of fledging death. Fledgings actually have a higher mortality rate when they leave the nest because they are no longer under the constant parental care. However, after a kookaburra gets past its first year of life his/her ability to survive greatly increases and he/she tends to survive for about twenty long prosperous years (Parry)!

Australian Species

The left most bird is a Laughing Kooka, while the bird on the right is a Blue-winged!

The general habitats of the two Australian species.

The Dacelo novaeguineae species. Listen to this kooka: https://www.youtube.com/watch?v=S0ZbykXlg6Q

The two Australian Kookaburras are dissimilar enough in their habitat, appearance and behavior to be classified as different species. The Dacelo novaeguineae, according to Strahan were “dubbed by Sydney settlers as the: giant Australian kingfisher.” The current common name, the laughing kookaburra, echoes its laughing call and preserves an aboriginal connection. Over the past couple centuries this kookaburra has accumulated numerous names: alarm bird, breakfast bird, bushman’s/settler’s/shepard’s clock, giant or laughing kingfisher, Ha Ha or Woop Woop pigeon, kooka, kookaburra, and laughing jackass. All of these in some form or another describe these 400 to 470 millimeter length birds. The laughing kookaburra is cream white with brown accentuating its eye strip, wings and back. Only dominant males can have a bright blue rump, this is a species specific trait! Their laugh is also unique to their species, it begins with a “kook-kook-kook” (rolling/gurgling noises) and grows as the rest of the family chimes in to a loud staccato “kook, koo, koo, koo, haa, haa, haa”. This laugh used to be only heard in eastern Australia, but the laughing kooka has since been introduced to New Zealand, Tasmania, King Island, and Western Australia. Currently it can be found in eastern Australia, southern Australia, and southwestern Australia, Cape York Peninsula, and south to Cooktown. Actually within these regions there are believe to be the Dacelo novaeguineae and the Dacelo novaeguineae minor; the minor species is a subspecies. The subspecies is smaller and common in the Cape York peninsula and Cooktown areas. Both of these forms of the species can be found within urban parks and gardens, eucalypt forests, and woodlands areas. Within these habitats their nests tend to be either in a hollow tree or in a termite mound (the northern race) (Strahan). Although the species is quite commonly found in the wild, it is at some risk due to the loss of tree-holes from land clearance and ingestion of pesticides; it would truly be a loss to have this lovely laugh disappear from the world.

The Dacelo leachii species. To listen to this kooka https://www.youtube.com/watch?v=bhrzu_LabII

The blue-winged kookaburra is similar to the laughing in many respects, like diet and vocal and visual behavior, however there are key difference. The common name of this bird is derived from the large blue patch on its wing. It also has various names that are similar to the laughing’s such as: Leach’s Kookaburra, Howling Jackass, and barking jackass. The tell-tale difference of the laughing and blue-winged kookaburra is their songs. Kookaburras are not visually conspicuous, but they are vocally. Instead of sounding like a mocking laugh, their songs are compared to a machine-driven hacksaw and begin with a howling scream starting with “huff, huff…”and ending with an “o wow ow”. If kookas did visually stand out against their leafy habitat then their appearance would also give away their species name. They are approximately 400 – 460 millimeters long with pale heads and dark streaks across the crown and face. These features are also coupled with bright hues of blue covering their wings and back. There is a subspecies, d.l. cliftoni, which has a completely white head. In both of these forms of the species, the males’ tails tend to be dark blue and are distinct from the females’ tails of evenly barred blue-black. The d. lechii can be seen from Brisbane to Darby and its subspecies is found in Western Australia. These birds are often around creeks, in the tropical woodland areas, or perching near melaleuca swamps. Within these habitats one may spot a family of 12, which is common for blue-winged; however the laughing kookas are usually in families no larger than 4 birds (Strahan). These blue-winged birds are fairly common and a least concern on the threatened list, so it should be secure for the next couple of decades!

During my time down under my interactions with this iconic, beautiful creature were limited but memorable. Each morning in Kakadu National Park, I woke up to the majestic melody of the blue-winged kookaburra. I didn’t have a chance to spot one, but I was lucky enough to see a laughing kooka in Manly. My Australian visit wouldn’t have been authentic without this awe inspiring jackass. 🙂

Photographer: Jenna Freedman!
This is the kookaburra I saw on Manly!

Work Cited

Christidis, Les, and Walter Boles. Systematics and Taxonomy of Australian Birds.      Collingwood, Vic.: CSIRO Pub., 2007. Web. 15 July 2014.

Forshaw, Joseph Michael., and William T. Cooper. Kingfishers and Related Birds.    Melbourne: Lansdowne, 1983. Print.

Parry, Veronica A. Kookaburras. Melbourne: Lansdowne Pty Lrd., 1970. Print.

Scott, Thomas A., trans. Concise Encyclopedia Biology. Ed. Friedrich W. Stöcker. Berlin:    Walter DeGruyter &, 1995. Web. 15 Jul 2014.

Strahan, Ronald. Cuckoos, Nightbirds & Kingfishers of Australia. Sydney, NSW: Angus &  Robertson, 1994.

Phylogeny

Class: Aves

Order: Casuariiformes

Family: Casuariidae

Genus: Dromaius

Species: Novaehollandiae

Dispersion of Ratites

As one of the seven species of flightless birds belonging to the ratite clade and native only to the Southern continents (its relatives include: living ostriches, rheas, cassowaries, kiwis, as well as the recently extinct moas and elephant birds), Dromaius novaehollandiae, commonly known as the emu,continue to fascinate evolutionary biologists who have been questioning their phylogeny for over a century.

Historically, there has been much contention over the origin of ratites. Before the theory of continental drift became widely accepted, there were two recognized arguments: that ratites came to be as they are by convergent evolution, or divergent evolution. The convergent evolution hypothesis claims that ratites are of polyphyletic origin, that they arose on any given continent from flying ancestors and then later became flightless and “convergently similar in anatomy and way of life to the ratites on other continents (Prager et al. 1976) .” According to the divergent evolution hypothesis, the ratites’ common ancestor was much more similar to them and reached their currently inhabited continents by walking across land bridges; this suggests that they are of monophyletic origin. Now that geologists have confirmed the existence of land bridges between the southern continents during the Cretaceous period, ornithologists mostly prefer the monophyly hypothesis and the theory of divergence is most commonly accepted.

Figure A

Figure B

Figure A shows the “geographic distribution of ratites and tinamous. The numbers within the dashed lines indicate, in millions of years ago, the times of disappearance of land bridges between the continent~ and islands shown. The ostriches, rheas, emus, and casso- waries, weighing 80-140 kg, are often known collectively as the “large ratites”, in contrast to the 2-3 kg kiwis. The tinamous, unlike the ratites, are able to fly; they are included in this figure since their phylogenetic relationship to the ratites is demonstrated. The extinct flightless moas and elephant birds existed in New Zealand and Madagascar, respectively (Prager et al. 1976).”

Figure B shows the “conjectural phylogenetic model for the origin of flight in 2 stages. The dark, striped, and clear areas represent flightlessness, non-sustained flight, and sustained flight, respectively. The number of species in the ratite-tinamou assemblage is less than I% of the nearly 9000 living bird species (Prager et al. 1976).”

Morphology and Species Diversity

Size (H): 1.5m – 1.9m (4.9ft – 6.2ft)

Weight: 18kg – 60kg (40lbs – 132lbs)

Top Speed: 40km/h (25mph)

Color: Black, Grey, Brown

Skin Type: Feathers

Distinctive Features:Enormous body size and large eyes

Ranging from 1.5m – 1.9m and weighing in at 18kg – 60kg, Dromaius novaehollandiae is Australia’s largest native bird, and second only in the world by height to its ratite relative, Struthio camelus (ostrich). Shaggy grey-brown feathers on the body and a naked, bluish-black neck and shoulders are characteristic of emus, as are reduced wings and long and powerful legs. Their feet have only three forward-facing toes and a small number of bones and associated foot muscles. They are the only birds with gastrocnemius muscles in the back of the lower legs. Their speed is attributed to their highly specialized pelvic muscles; they are Dromaius novaehollandiae’s “flying muscles,” in the sense that they contribute the same amount to total body mass as the flight muscles of flying birds.

Before European settlement, three different Dromaius species were abundant in Australia: Dromaius novaehollandiae, that remains common, and the small emus, Dromaius baudinianus and D. ater, which both became extinct shortly after European arrival. The island emus of Tasmania and the Maria Island have become extinct, leaving only the introduced population of Kangaroo Island to thrive in its breeding grounds.

Dispersion of Emus

The total population varies depending on rainfall, but it is estimated that the emu population is 625,000-725,000 and growing, with 100,000-200,000 in Western Australia and the remainder in New South Wales and Queensland. There are three extant subspecies: D. novaehollandiae novaehollandiae, which is primarily found in the southeast; the northern D. novaehollandiae woodwardi; and D. novaehollandiae rothschildi in the southwest. The three subspecies differ slightly in morphology; although all three are large and flightless, D. novaehollandiae woodwardi are slender and paler than the other two. D. novaehollandiae novaehollandiae sports a whitish ruff when breeding where D. novaehollandiae rothschildi has none and is darker.

 Ecology

Diet: Omnivore

Favorite Food: Fruit

Main Prey: Fruit, Seeds, Insects, Flowers

Lifestyle: Flock

Habitat: Open grasslands with bushes close to water

Predators: Human, Wild dogs, Birds of prey

Life Span: 12 – 20 years

Average Clutch Size:11

Dromaius novaehollandiae is endemic to Australia and lives throughout most of the continent. While climactic conditions (that affect food and water supply) may influence them to move, Dromaius novaehollandiae are rarely found in rainforest or arid areas and prefer to inhabit sclerophyll forests and savanna woodlands. They will reside in one area for as long as supplies last, and then travel up to hundreds of kilometers to a more suited location. They have even been known to traverse 15 to 25 kilometers a day.

As an omnivore, Dromaius novaehollandiae’s diet consists of plants, seeds, fruits, insects, small animals, and animal droppings. 

During nesting season (winter), the male and female remain together for about five months (this includes courtship, nest building and egg-laying). The female is the dominant partner during pair formation, and leaves the male to perform all of the incubation. At this time, the females will sometime find another male with whom to breed while her former male is bound to the nest, going the entire incubation period of 55 days without eating, drinking, or defecating.

Once they have hatched, the striped chicks stay with their father for four months, or until they can feed by themselves. They stay close together until they are six-months-old, newly full of feathers and ready to take on the world alone. They reach full maturity at 20 months at which time they may begin breeding .

Newly hatched chicks

  Conservation Status 

All three subspecies of Dromaius novaehollandiae have been deemed of least concern and are in fact growing in numbers. However, in recent years there has been a growing interest in the emu farming industry as the large birds are prized for their meat, leather, oil, and feathers. But with the average emu pair producing up to ten eggs a year under decent captive conditions, Australia’s largest native bird as at no risk of extinction.

Works Cited 

Cracraft, Joel. 1974. “Phylogeny and Evolution of the Ratite Birds.” Ibis 116 (4): 494–521. doi:10.1111/j.1474-919X.1974.tb07648.x.

“Isolation and Characterization of Micro Satellite Loci in the Emu – Google Scholar.” 2014. Accessed July 29. http://scholar.google.com/scholar?q=isolation+and+characterization+of+micro+satellite+loci+in+the+emu&btnG=&hl=en&as_sdt=0%2C5.

Milàn, Jesper. 2006. “Variations in the Morphology of Emu (dromaius Novaehollandiae) Tracks Reflecting Differences in Walking Pattern and Substrate Consistency: Ichnotaxonomic Implications.” Palaeontology 49 (2): 405–20. doi:10.1111/j.1475-4983.2006.00543.x.

Prager, Ellen M., Allan C. Wilson, David T. Osuga, and Robert E. Feeney. 1976. “Evolution of Flightless Land Birds on Southern Continents: Transferrin Comparison Shows Monophyletic Origin of Ratites.” Journal of Molecular Evolution 8 (3): 283–94. doi:10.1007/BF01731001.

Reid, J, and M Fleming. 1992. “The Conservation Status of Birds in Arid Australia.” The Rangeland Journal 14 (2): 65–91.

Photos and Fast Facts 

http://a-z-animals.com/animals/emu/

http://beautyofbirds.com/emus.html

Intro and Ancestry

While turtles are admired for their cute features and leisurely lifestyle, they actually hide a great deal of history under their shells. Australia is home to a diverse range of marine turtle species. Analyzing the distribution of these species provides a great deal of insight into the ecological history of the Australian biomes they call home.

The order Chelonia contains all turtle species, many of which are found in Australia. The existence of turtles in the land down under can be traced through the fossil record to an ancestor, Proganochelys Quentstedi, which lived approximately 200 million years ago. This progenitor wasn’t a shell dweller in the traditional sense. This turtle was unable to retract its neck into its shell; instead it flexed its neck in a vertical plane. To this day, a defining characteristic of its descendants is an ability to flex the forward-facing head at the neck joint, even when retracted in the shell. From this common ancestor, two main lineages evolved: Cryptodira and Pleurodira. The order Cryptodira lives mainly in temperate areas in the Northern hemisphere, and the only members of this family that exist in Australia are the marine turtle families Cheloniidae and Dermochelyidae. Members of Pleurodira are found in Australia, New Guinea, and South America, making it endemic to the southern hemisphere. This group is unique, as it is the only group of reptiles with a distinct Gondwanan origin.

Cladogram Representing the Cheloniidae http://jpaleontol.geoscienceworld.org

The fossil record of Australian turtles is based mainly on osteological comparisons of skull anatomy. The earliest date back to two taxa of Early Cretaceous origin, the Chelidae and Carettochelyidae. Most of the historic groups have died, but the majority of remaining species of freshwater turtle are classified in the Chelidae family. Today, there are only seven total species of sea turtle, and six of the seven can be found in Australia. The six species found in Australia are the green, loggerhead, olive ridley, hawksbill, leatherback, and flatback. The flatback sea turtle, Natator Depressus, is endemic to the waters around Australia and Papua New Guinea. The flatback turtle has the most limited habitat of all, preferring shallow, soft-bottomed waters. Large populations of flatbacks rarely leave the protected waters of the continental shelf. Due to the threats imposed by habitat loss and predation by non-native species, the flatback turtle is classified as vulnerable to extinction.

Flatback Sea Turtle
www.seaturtles911.org

Biogeography

The sea turtle population of Australia is of particular interest to many biogeographers. While marine turtles are found around the globe, they typically gravitate to a common habitat, preferring tropical and temperate waters to those at colder temperatures. The vast majority of sea turtles are found off the coast of northern Australia, and in areas off the coast of Queensland, though some nesting sites have been found on the coast of the Northern Territory and Western Australia. Temperature is a limiting factor in turtle reproduction, because turtles rely on warm sands and soils to form their nests and incubate their eggs. Sea turtles are especially vulnerable to extreme temperature changes. For sea turtles, sexual differentiation depends on the sand temperature during the middle third of the incubation period. Warm temperatures yield female hatchlings, while cooler temperatures yield males. In order to produce a viable population capable of reproduction, eggs must be laid in a temperate area.

 Diet

There is a great deal of variety in diet between the sea turtle species. Some are omnivores that enjoy both plants and animals, while others have more specialized diets consisting of such things as jellyfish or sea sponges. Jaw morphology provides a great deal of insight into what a sea turtle may enjoy eating. For example, green sea turtles have a beak with serrated edges that allows them to munch on sea grasses and scrape algae off of hard surfaces. Loggerheads have strong jaw muscles that enable them to crush shellfish. The huge leatherback turtle has pointed jaw cusps so they can grab jellyfish and pierce their gelatinous bodies. Barbed cusps in the back of the throat ensure that their meal goes down in the right direction.

A Leatherback turtle’s mouth  http://museumvictoria.com.au/about/mv-blog/categories/melbourne-museum/.

Another unique aspect of a sea turtle’s diet is how it changes from hatchling to adult. Hatchlings are mainly carnivorous, eating a variety of items such as crustaceans, fish eggs, and pelagic mollusks. Adults of most species are herbivores, though there are some strange exceptions. Hawksbill sea turtles are known as spongivores; they have a specialized diet consisting only of sponges. The species of sponge in their diet are actually poisonous to nearly all other species, so they face much less competition for food resources. Loggerheads remain carnivorous for their entire lives, consuming crabs, conches, and whelks. One of the most interesting facets of the dietary habits of sea turtles is the extensive migration they make in search of food. The leatherback has been known to traverse the entire Pacific, following swarms of jellyfish. The sea turtles of Australia are also important for maintaining the health of the coral reefs. Turtles eat the algae surrounding the corals that would otherwise obscure the coral polyps.

 Conservation Efforts

In Australia, all 6 species of sea turtle are protected under the government’s Environment Protection and Biodiversity Conservation Act. The loggerhead, leatherback, and olive ridley are endangered, while the green, hawksbill, and flatback are classified as vulnerable. A national recovery plan for marine turtles was adopted in 2003, and regulates factors such as fishing and habitat destruction in an attempt to allow populations to recover. An interesting component of the restoration effort is how it takes the needs and culture of the native people into account when imposing restrictions on hunting.

Surprisingly, it is legal for Aboriginal and Torres Strait islanders to hunt turtles and use them for food and ceremonial purposes. The native peoples of Australia have a unique relationship with the turtle population. Marine turtles are very important in their culture not only for their meat and eggs, but also for their traditions and customs. Hunting these species is an important way of maintaining kinship and social standing, and their shells have been used in rituals and ceremonies. Aboriginal communities are in the process of working collaboratively to find ways to respect both the ancient culture and the ancient creature.

 Risks Faced by Marine Turtles

Some of the greatest modern risks facing marine turtles are those imposed by commercial fishing nets. Because sea turtles are migratory creatures, they are likely to encounter prawn-trolling ships that use large nets to capture as many prawns as possible. The turtles can become trapped in the net, and many asphyxiate. In order to prevent this, new nets are being developed with turtle exclusion devices: separate parts of the upper net that allow the turtles to escape while still retaining as many prawns as possible. This solution satisfies both the commercial fishermen and the ecological conservationists, as it allows for a profitable trade to continue while preventing unintentional harm to a vulnerable species. Education efforts in Australia and beyond intend to help ensure that sea turtles are around for many generations to come.

Successful Implementation of a Turtle Exclusion Device
www.nmfs.noaa.gov

Works Cited

Fujita, M., Engstrom, T., & Starkey, D. Turtle Phylogeny: insights from a novel nuclear intron. Molecular Phylogenetics and Evolution, 31, 1031-1040.

Gaffney, E. A Review of the Fossil Turtles of Australia. American Museum of Natural History, 27, 1-38.

Jones, T., Bostrom, B., & Hastings, M. Resource requirements of the Pacific leatherback turtle population. PLoS One, 7.

Legler, J., & Georges, A. Biogeography and Phylogeny of the Chelonia. Fauna of Australia, 18, 1-18. Retrieved June 30, 2014

Morreale, S., Ruiz, G., & Spotila, J. Temperature-dependent sex determination: current practices threaten conservation of sea turtles. Science, 216, 1245-1247.

Marine turtles. (2014). wwf. Retrieved July 24, 2014, from http://www.wwf.org.au/our_work/saving_the_natural_world/wildlife_and_habitats/australian_priority_species/marine_tu

Diet of the Sea Turtle. (2014). SEE Turtles. Retrieved July 19, 2014, from http://www.seeturtles.org/sea-turtle-diet/

Evolutionary history/Biogeography

Marsupials are some of the most bizarre and fascinating creatures on Earth. We know them stereotypically as kangaroos and wallabies, but there are in fact 280 living species. More specifically, the family Macropodidae includes all larger marsupials: extant kangaroos and wallabies for a total of 54 species.

Marsupial distribution is interesting as this class of mammals resides not only in Australia but also throughout South America and as far north as Canada. The ancient evolutionary history of the marsupial is somewhat controversial and only recently has one theory emerged. This widespread and seemingly arbitrary dispersal traces its roots back to the supercontinent Pangaea and its southern component, Gondwana.

http://www.gambassa.com/gambassafiles/images/images/1919/gondwanaland_breakup_v1.jpg

Scientists now believe that the initial phase of marsupial diversification and radiation might have occurred in Laurasia towards the end of the Cretaceous period. The fossil record indicates that both placental and marsupial mammals were evolving quickly at this time. However, molecular evidence indicates the marsupials that eventually colonized Australia are not descendants of the original radiation. Geology also supports this as North America became separated from South America with the meteor impact that ended the Cretaceous. Therefore a second radiation must have occurred at the end of the Cretaceous period and beginning of the Paleocene. This theory is supported by a strong genetic connection to South American marsupials, which are thought to have quickly radiated due to mass reptile extinctions in the late Cretaceous. These extinctions opened ecological zones that were rapidly filled through adaptation. At this time in Earth’s history, South America and Australia remained attached to Antarctica forming the landmass Australasia. Additionally, Antarctica was not the icy continent that it is today, and marsupials would have been able to easily traverse this region. Much debate exists between scientists as to the exact method of marsupial colonization. Some believe that a single wave traveled to what became Australia and never returned. Others think that there must have been considerable back and forth movement through Antarctica for these strong genetic similarities to exist.

Nilsson, M. A., Churakov, G., Sommer, M., Tran, N. V., Zemann, A., Brosius, J., & Schmitz, J. (2010). Tracking Marsupial Evolution Using Archaic Genomic Retroposon Insertions. PLoS Biol, 8(7), e1000436. doi:10.1371/journal.pbio.1000436

Early fossil evidence for marsupials in Australia was only recently discovered in southern Queensland. These 55 million year old fossils resemble Australian bandicoots and dasyurids, but more interestingly several species of Peruvian marsupials, further evidence of the migratory connection between South America and Australia. This ancestor would not have hopped like modern macropods but lived in trees. One of the most interesting aspects of marsupial biogeography is their tremendous success and rapid radiation in Australia compared to other placental mammals. Even early marsupials were probably highly adapted to living in harsher environments. They were better equipped to survive the journey from South America to Australia due to unique physiology that allowed them to travel long distances efficiently. Upon reaching Australia, these ancestors found a place with substantially open niche space and this factor likely aided their rapid radiation. A fascinating comparison shows the convergent evolution of placental mammals on other continents and marsupials in Australia. This also shows the similarities between placental and marsupial mammals.

The first macropods are thought to have evolved around 23 million years ago but still were drastically different from modern kangaroos and wallabies. It wasn’t until a global cooling event that occurred 14 million years ago that macropods began to look like their modern descendants. As the world cooled it also dried, particularly in Australia and the landscape was now sparse and open rather than densely forested. Subsequent evolution resulted in anatomical and metabolic adaptations that allowed these animals to travel efficiently between food sources that were increasingly far apart. Other modifications include changes to teeth and jaws as well as specialized stomachs that permitted consumption of hard-to-digest grasses.

Habitats

Macropodidae are extremely successful because they can live almost anywhere. Preferred habitat depends on the species but these animals can be found in deserts, woodlands, and rainforests. Macropus rufus (red kangaroo) technically inhabits nearly all of Australia, excluding the northeast most part where the climate is too wet. This species prefers grassy plains with some tree cover for shade. Alternate habitats include mulga scrub, saltbrush scrubland, extremely dry grassland, and even deserts.

Diet and Feeding

All kangaroos and wallabies are herbivores, eating mostly grass but also leaves and flowering plants. Red kangaroos have specialized feeding behavior and diet selection that helps them to thrive in a variety of conditions. During times of prolific rain their diet consists primarily of forbs. In the dryer months, shrubs are increasingly consumed and during severe drought, red kangaroos consume grasses almost exclusively. They intelligently make the connection between rain and food and will travel long distances to places that have recently received precipitation because of good grazing at that location. As human impact on the land has grown, red kangaroos have learned to benefit from this intrusion by grazing on the open plains cultivated by cattle farmers during desperate times.

Adaptations and reproduction

The macropodidae family displays many adaptations that allow for widespread success but the most fascinating are those that allow them to endure severe heat and dryness. Instinctively these animals seek shelter under shading flora (typically mulga bushes or saltbushes). They also stand with their tail beneath their bodies, effectively shading themselves. Like other mammals, kangaroos pant but this is particularly useful in the dry habitats of Australia because it effectively cools the core and brain without requiring loss of precious water. Unlike some other mammals, macropodidae can also sweat. Instead of sweating indiscriminately, this method of cooling is only utilized during periods of intense exercise.

Besides their unique pouches, kangaroos are perhaps best known for their unique mode of transportation, hopping. Using a combination of elastic tendons and extremely large feet, macropods are able to jump incredible distances in a single bound. While not effective at slow speeds (most kangaroos use a pentapedal gait for this), hopping is significantly more energy efficient at high rates of travel. Studies show that above 18 km/hour, hopping requires much less energy than quadrapedal running. To travel faster, a kangaroo increases the distance each hop carries it, rather than increasing the rate of physical exertion.

Mammalian reproduction is can be very difficult and physically taxing, but it’s also critical for species survival. Kangaroo reproductive habits and anatomy are both strange and useful. Most macropodidae are able to breed all year round, and this opportunistic reproduction allows them to easily survive natural disasters and other short-term population declines. In the case of the red and grey kangaroos and some other macropodidae species, mothers can have independent young approximately every 240 days. Unlike other mammals, kangaroos have double the sex organs. This fact combined with pouch development (rather than extended uterus gestation) means that a female can mate just days after giving birth. A phenomenon known as embryonic diapause lets the fertilized egg effectively remain dormant within the uterus until the already-born joey leaves the pouch. After approximately 35 days, the gestation period concludes and the tiny joey climbs into its mother’s pouch to begin suckling. Joeys will predominantly reside in the pouch until they are around 235 days old, at which point they leave for good.

Conservation

Unlike many other unique species of Australia, most macropodidae maintain a healthy (sometimes too healthy) population. Larger varieties such as the red kangaroo thrived with the expansion of Europeans into Australia. Dingo populations were reduced and well-tended fields meant to feed cattle provided a reliable source of food. In fact, several state governments have recently published management strategies for excessive populations that include harvesting.

However, there are some localized threats including rural land use and urbanization. Kangaroos are often attracted to roadside habitats, probably because they tend to be less dense but sadly, the fragmentation of these areas by roads results in vehicle collisions. Habitat loss has the potential to increasingly effect macropod species that require wooded areas such as the tree kangaroo since these habitats are already somewhat rare in Australia. Fortunately the macropodidae group appears to be predominately safe from the extinction threats that affect many other animals in Australia and most species have and IUCN status of ‘least concern.’

Sources:

Archer, M., & Bartholomai, A. (1978). Tertiary mammals of Australia: a synoptic review. Alcheringa, 2(1), 1-19.

Bailey, P. T. (1971). The Red kangaroo, Megaleia rufa (Desmarest), in north-western New South Wales. 1. Movements. Wildlife Research, 16(1), 11-28.

Coulson, G., & Eldridge, M. (2010). Macropods: The Biology of Kangaroos, Wallabies and Rat-kangaroos. CSIRO PUBLISHING. Retrieved from http://books.google.com/books?id=rQQqQYKQkBYC

Cowen, R. (2013). History of life. John Wiley & Sons.

Dawson, T. J. (1995). Kangaroos: the biology of the largest marsupials. Ithaca, N.Y: Comstock Pub. Associates.

Dawson, T. J., & Taylor, C. R. (1973). Energetic cost of locomotion in kangaroos.

Kirsch, J. A. W. (1984). Marsupial origins: taxonomic and biological considerations. Vertebrate zoogeography and evolution in Australasia, 627-631.

Nilsson, M. A., Arnason, U., Spencer, P. B. S., & Janke, A. (2004). Marsupial relationships and a timeline for marsupial radiation in South Gondwana. Gene, 340(2), 189–196. doi:10.1016/j.gene.2004.07.040

Springer, M. S., Kirsch, J. A., & Case, J. A. (1997). The chronicle of marsupial evolution. Molecular evolution and adaptive radiation, 129-161.

Tyndale-Biscoe, H. (2005). Life of marsupials.

Class- Aves

Order- Sphenisciformes

Family- Spheniscidae (Penguins)

Evolutionary History of Penguins

Penguins, Sphenisciformes, are the only order within the class Aves that are a homogeneous group of flightless, aquatic birds (Hoyo 140). Sphenisciformes comprises only one family, Spheniscidae. There are 17 currently recognized species: Aptenodytes forester, A. patagonicus, Eudyptes chrysocome, E. chrysolophus, E. pachyrrhynchus, E. schlegeli, E. sclateri, E. robustus, Eudyptula minor, Megadyptes antipodes, Pygoscelis adeliae, P. antartica, P. papua, Spheniscus demersus, S. humboldti, S. magellanicus, and S. mendiculus (Bertelli 211).

Divergence from a common ancestor happened probably in the late Eocene, 45 million years ago (Marchant 125). Penguins are descended from ancestors who had the power of flight but their “evolutionary energy” has “transformed their wings into flippers” (Bertelli 211, Hoyo 140). Skeletal modifications have developed their upright locomotion, adapting these sea birds to a lifestyle suited for both land and water (Bertelli 211). Their closest relatives, according to a combination of morphology and mitochondrial sequences, appear to be the divers, Gaviiformes, the petrels and the allies, Procellariiformes (Hoyo 140).

The first remains of a fossil penguin were found in New Zealand, the species was named Palaeeudyptes antarcticus by T. H. Huxley in 1859 (Hoyo 140). The fossilized bone found displays a “fusion of the tarsus and the metatarsus in a way peculiar to penguins” (Hoyo 140). Penguin fossils have since been discovered in New Zealand, Australia, South America, Antarctica, southern Africa and various islands of the Antarctic and sub-Antarctic (Hoyo 140). Penguins clearly originated somewhere in the southern hemisphere, but the exact location is still to be determined (Hoyo 140). In Australia, New Zealand and the Antarctic penguin remains have been dated as far back as the late Eocene. No definite penguin remains have been found from earlier periods. The oldest penguin remains found in South America date back only as far as the late Oligocene (Hoyo 140). The oldest penguin remains found in South Africa date only to the late Miocene (Hoyo 140). While a more exhaustive evacuation for penguin remains is necessary, one can hypothesize that penguins colonized these areas later (Hoyo 140).

There are 21 genera and 32 species of extinct penguins known to science today (Hoyo 144). The extinct species were more diverse than the four extant genera, Aptenodytes, Eygoscelis, Eudyptula and Spheniscus, and reached greater sizes (Hoyo 140). The number of extant species in the family Spheniscidae is widely debated. Currently, 17 is the most commonly accepted number of species.

Morphology

All living penguin species are similar in structure and coloration (Hoyo 141). They all have “large heads, short necks and elongated [bodies]” (Hoyo 141). Penguins’ have short, wedged shaped tails that they use as a prop when standing on land (Marchant 144). Their legs are “situated far back on the body causing an upright stance” (Hoyo 141). All penguins walk with a similar waddling, gait however they often prefer to toboggan on their bellies when on land (Hoyo). Penguins are a highly specialized group of seabirds; “their structure and physiology have been molded both by their marine habitat and the climatological peculiarities of their environment” (Hoyo 141) Most species of penguins exhibit “highly modified plumage” for insulation in cold conditions (Bertelli 209). Their feathers are “short, with broad flat rachis, and closely spaced barbs, especially near rachis and tips”. Interestingly their feathers are “considerably less water-repellant than those of other water birds” (Bertelli 209). Penguins also have small downy feathers that serve as a second layer of insulation (Bertelli 209). In general penguins coloration is “blue-black to grey-blue above, and white below” (Bertelli 209).

Biogeography & Species Diversity

Penguins can swim exceptionally long distances. Therefore they seem unsuited for a biogeographical study. However, they “exhibit remarkable nest-site fidelity, so the breeding ranges of penguins offer great potential for historical biogeographical reconstruction” (Bertelli 213). As a group penguins are isolated to the southern hemisphere. Though popularly associated with the southern polar region, most species breed on sub-Antarctic and even cool temperature islands (Marchant 125). The temperature range of the family is massive! Galapagos Penguins occur in “waters of 15 degrees Celsius to 28 degrees Celsius, while the emperor Penguin occurs in temperatures ranging from -60 degrees Celsius to 0 degrees Celsius” (Marchant 144).

Penguin distribution “is not random but closely related to cold water currents and food availability” (Marchant 125). The highest density of penguins occurs near convergences and upwelling (Marchant 125). These waters are areas of “high marine productivity that support extensive food webs” (Stahel 14). High levels of nutrients “result in increased plankton abundance, which in turn supports krill, fish and squid”, the exact diet of all species of penguins (Stahel 14). Species of the Antarctic and the sub-Antarctic feed on krill and cephalopods, while those that live further north tend to feed on fish (Marchant 144). Apentenodytes and Eudyptes are offshore feeders, while the rest all feed in inshore waters (Marchant 144).

Penguins’ bills are “composed of horny plates and its shape is adapted to suit the typical prey” (Hoyo 141). The bills are long and thin in species that are fish eaters, but “shorter and stouter in those that take plankton” (Hoyo 141). There are “distinctive bill-plates” in all species of penguins, as there are in all species of petrels (Stahel 14). For example the Eudyptes have bills that are very heavy (Hoyo 141).

Penguins become steadily larger as one travels south into colder temperatures, this is known as Bergmann’s Rule (Hoyo 141). The principle states “optimum size changes with the increased energy requirements in colder zones” (Hoyo 141). The species diversity by temperature is also reflected in there morphology. For example the area of bare skin near Penguins’ feet is often bigger in penguins of warmer regions (Stahel 14). One important exception to Bergmann’s Rule is the Gentoo Penguins; “the smallest representatives of this species are found in the southernmost, coldest regions of its range” (Hoyo 141). On the subject of size, sexual dimorphism is also present in all species of penguins to a very small degree. In general male penguins are found to be ever slightly larger than females. This difference is most notable in the genus Eudyptes (Hoyo 141). The greatest variety between penguins’ species is exhibited by their plumage coloration. Face and crown coloration are often distinct to each unique species (Stahel 14). Coloration varies from yellow to orange plumes or other colors; “Patterns of head are the most important character for field identification at sea” (Stahel 14).

Ecology

Penguins spend the majority of their lives in the southern oceans but nesting habitats varies with distribution. Some species are suited to breed in a wide variety of places while others have more specific needs. Some of the more surprising types of nesting habitats include: Emperor penguins that use frozen seas to breed, Chinstrap Penguins that breed on steep slopes, Fiordland Penguins in wet, coastal rain forests and the Galapagos Penguins in volcanic caves or cracks in the rock (Marchant 144). Australia’s very own Little Penguins’ dig holes in its coastal sands for their breeding season (Fortescue 365).

Conservation Status

In general Antarctic and sub-Antarctic penguins are most abundant, while temperate and tropical penguins are less numerous (Marchant 126). The inshore feeders of these lower latitudes have suffered from over fishing and human interference resulting in damage to breeding grounds (Fortescue). These negative environmental factors have caused a noteworthy decline in temperate to tropical penguin populations. The Yellow-eyed Penguins are a tropical penguin species that’s population is worryingly small (Marchant 126). In regards to the Antarctic and sub-Antarctic penguins “uncontrolled taking of adults and eggs for food and bait for whalers and sealers, from the 18^th century to early twentieth century, reduced or destroyed some populations”. The King Penguins, in the sub-Antarctic and Antarctica have suffered the greatest (Marchant 126). However, an “increase of some species in the last 30 years is attributed to greater availability of krill because of a decrease of Antarctic whales” (Marchant 126).

As human society enters a time of amplified conservational planning, “the nature of habitats and ecological data which contribute to the well being of species” becomes essential (Fortescue). According to the Endangered Species Committee of 1992 certain penguin species will be more likely to be threatened with extinction than others. Those “endemic to islands, birds more than 500g, and those that nest on the ground” are most threatened. Through a biogeographical examination of species one can see that Australia’s Little Penguin, a1kg bird, ground nesting, and island-dweller, is a species most in danger of extinction (Fortescue). To protect the Little Penguins and other species in similar danger, increased data and conservational laws are imperative.

Works Cited:

Bertelli, Sarah, and Norberto P. Giannini. “A Phylogeny of Extant Penguins (Aves: Sphenisciformes) Combining Morphology and Mitochondrial Sequences.” Cladistics The International Journal of the Willi Society 21.3 (2005): 209-39. Print.

Dann, Peter, Ian Norman, and Pauline Reilly. The Penguins Ecology and Management. Chipping Norton NSW: Surrey Beatty & Sons Pty Limited, 1995. Print.

Fortescue, M. E. Biology of the Little Penguin Edyptula Minor on Bowen Island and at Other Australian Colonies. Vol. 1995. N.p.: Penguins, n.d. Print.

Hoyo, J., A. Elliott, and J. Sargatal. Handbook of the Birds of the World. Vol. 1. Barcelona: Lynx, 1992. Print.

Marchant, S., and P.J. Higgins. “Sphenisciformes.” Handbook of Australian, New Zealand & Antarctic Birds 1 (1998): 125-259. Print.

Peucker, Amanda J., Peter Dann, and Christopher P. Burridge. “Range-Wide Phylogeography of the Little Penguin (Eudptula Minor): Evidence of Long-Distance Dispersal.” The Auk (2009): 397-408. BioOne Online Journals. Web. 14 July 2014. <http://www.bioone.org/doi/abs/10.1525/auk.2009.08055>.

Stahel, Colin, and Rosemary Gales. Little Penguin Fairy Penguins in Australia. Kensington: New South Wales UP, 1991. Print.

Introduction & Evolutionary History

Although Steven Spielberg’s “Jaws” has become part of cinematic history, it inaccurately depicts sharks. The film gave viewers not only one of the scariest motion pictures of its time, but also a negative view of these animals. The “man-eating machine” has an extensive evolutionary history and an important ecological role in marine ecosystems. However, their reputation amongst people has made it a challenge to raise awareness about conservation issues.

Sharks belong to the class of chondrichthyes, which also consists of rays, skates, and chimeras. This class is part of the infraphylum gnathostomata, the jawed vertebrates. Other characteristics of this super group include teeth and paired appendages such as pectoral fins in the first gnathostomes. These creatures roamed all over the “gondwanan waters”- there was no unique place to find them. Existing as early as the late Ordovician 460 million years ago, the “Jaw Mouths” specialized into four slightly different classes: the extinct Placodermi and Acanthodii and the extant Chondricthyes and Teleostomi.

Time scale of gnathostomes. (http://rsbl.royalsocietypublishing.org/content/3/2/197/F2.expansion.html)

Placoderms were armored fish that existed from the Silurian to the end of the Devonian. Besides being the earliest jawed fishes, records show that they were the first in the fossil record to show pelvic fins. Even though the placoderms had some of the most important developments in early vertebrate evolution, they could not compete with the extant gnathostomes that exploded during the Carboniferous period. Chondricthyes appear on the fossil record about 420 million years ago, which marks the end of the Devonian and the end of the placoderms. The armored fish could no longer compete against the early cartilaginous fish such as the Cladoselache and Ctenacants. The clade is separated into two subclasses, Holocephali and Elasmobranchii, that may have diverge 410 million years ago and diversified in the Devonian. The Carboniferous period is referred to as the “Golden Age of Sharks,” because the Elasmobranchiis underwent adaptive radiation that eventually led to 45 families of shark to arise. Further diversification during the Jurassic Period led to the rise of the batoids, which includes the skates and rays. Since then there has been two major sister clades within the Lasobranchii: Batoidea (skates and rays) and Selachii (sharks).

Phylogeny of Chondrychthies (Wikipedia)

Selachii and their Characteristics

The sharks and batoids have many similarities. For example, most live in marine habitats with very few that have adapted to freshwater ecosystems. They also tend to grow to a considerable size due to the flexibility of their cartilaginous skeleton. Being cartilaginous fish hints that they lack true bone. Only their teeth, and sometimes their vertebrae, are calcified. Due to this reason, it is difficult to find complete remains of these organisms since preservation and fossilization requires very special conditions. Since the jaw is not composed of true bone, the teeth become somewhat unattached and these fish constantly lose their teeth. Any species of shark can grow up to 30,000 teeth throughout their lifetime.

Other defining characteristics include the absence of swim bladders, two-chambered heart, and placoid scales. The placoid scales, which are also known as dermal denticles. These scales are sharp, small-toothed like scales that act as the skin. The shape of these scales helps Selachiis swim faster. Rays, on the other hand, secrete a mucous layer to serve as their skin, providing protection against bacteria and other infections. However, the most defining characteristic of this group is the ampullae of Lorenzini. These sensors provide the ability to detect electricity in the water, which is an ability that greatly helps in the search for food. The development of this “sixth sense” may have played a huge role in the success of sharks and served as a huge advantage in competition against the now extinct placoderms.

Placoid Scales (http://aqfi.uaex.edu/people/faculty/akelly/z-agoodwin-and-files/Web-Files/Delete/BIOF%20Web%20page%202011/Text/3%20Skin,%20scale,%20muscle/Text3lnk.html)

Ampullae of Lorenzini (http://www.doe.ky/marine/sharks/shark-biology/)

Reproduction is basically the same for the two classes. There is internal fertilization by the use of two pelvic male claspers. There is diversity in the way that offspring are born. They can either give live birth to “pups” or give “birth” to an egg with the fully developed embryo inside. A great number of species are oviparous, simply laying their egg cases amongst rocks and kelp forests where the embryo grows and develops.

Shark Egg Case (http://www.sharkfriends.com/lounge/index9.html)

The differentiation between the Selachiis and the Batoids is more evident in their body shape, and location of their gills. Rays and skates have flat bodies that are usually in the shape of a diamond or oval. Unlike rays and skates, sharks have their gill arches on the sides of their bodies

Ecology and Background

Sharks are labeled as apex predators since they are at the top of marine food chains. Majority of sharks become active after dusk. For the most part they prey on smaller fish. The most recent sharks, such as the great white and bull sharks, prey on larger animals such as seals, sea lions, dolphins, and even some sea birds. Although they comprise about 1% of all living fishes, their ecological role is important in keeping marine ecosystems balanced. Being at the top of the food chains, sharks keep populations of certain prey at healthy levels by eating the diseased or dead animals.

Food Chain (http://shaaark.com/index.php/shark-cartoon-173/)

They are mostly found in tropical and temperate waters worldwide and many species have extensive migratory patterns. About 400 species are found worldwide where 170-180 of them inhabit Australian seas and about 70 are believed to be endemic. The Coral Sea off the coast of Queensland contains more than 50 of these species. Australian coasts are home to some of the most impressive shark species, such as the Great White, Whale, Basking, Tiger, and Bull sharks.

Australian Species

The infamous “Jaws” protagonist is a Great White Shark, the largest predatory fish on the planet. It can be easy to understand why it is considered the most threatening species, growing up to an average of 15 feet in length. It is found worldwide in cool to temperate shallow seas but is commonly seen in Australian waters. Although they have and pretty lengthy lifespan of 25 years, they do not reach sexual maturity until they are 20 years old. This late sexual maturation presents a challenge in their conservation. Currently, it is believed that there are about 10,000 Great Whites left in the wild.

Great White Shark (http://animals.howstuffworks.com/fish/sharks/great-white.htm)

Great White Distribution Map (http://www.animalfactguide.com/animal-facts/great-white-shark/)

The Whale Shark is another species that although migratory, it spends a lot of time in Australian waters. They are the largest living cartilaginous fish whose ancestry goes back to the Jurassic and Cretaceous periods. They are one of the only filter feeding sharks found in planet. Besides their enormous size, they are usually recognized by their unique colorization. The pattern of lines and spots on their skin allows them to blend in to their surroundings. These sharks are currently listed as vulnerable.

Whale Shark (http://news.nationalgeographic.com/news/2014/01/140129-whale-shark-endangered-cites-ocean-animals-conservation/)

Whale Shark Distribution (http://www.usm.edu/gcrl/whaleshark/distribution.php)

Conservation

More than 200 shark species are listed as threatened where 50 of them are vulnerable. Only the Great White, Whale, and Basking sharks have been protected internationally. Many of these sharks have been victims to over fishing issues around the world. However, the most concerning cause for plummeting shark numbers is the shark finning industry. This industry has been an important factor in reducing shark populations. A study estimated that about 100,000 sharks of various species are killed at the hands of fishermen in search for the famous shark fins. The shark fins are a delicacy in various Asian countries, where the cartilage from the fins are used the primary ingredient in shark fin soup. Various countries have begun to ban the consumption of these products, becoming aware that shark populations are reaching extremely unhealthy levels.

Shark Finning (http://greatecology.com/thought-safe-water/)

Although the recent limitations on the shark finning industry have helped certain shark species, conservation of these animals is still a huge challenge. A lot of people do not see sharks as an important species that should be saved; especially because of their negative reputation. Sharks have been the cause for various deaths in the ocean, causing for people to be scared rather than being appreciative of them. However, it is important to emphasize to such believers that sharks are not “man-eating machines” and instead are one of the most important keys to healthy marine ecosystems.

Australia became the 14^th country to sign the Memorandum of Understanding on the Conservation of Migratory Sharks. This Memorandum was developed under the Convention of the Conservation of Migratory Species. This treaty covers seven shark species, where six of them are mostly found in Australian waters. Two of the six species are the Great White and Whale Sharks. In 1999, the Environment Protection and Biodiversity Conservation Act made it an offense to kill, trade, keep, transfer, or injure any threatened species on Australian government land or Commonwealth waters without a permit. The Act also listed various shark species that were legally caught by fishers as threatened.

The Selachii clade is one of great diversity. It has been one of the most successful clades in evolutionary history; being present since the a bit before the Carboniferous period. They have an important ecological role in oceans worldwide. However, their numbers are dwindling at rapid rates and if further action is not taken, the only place where these incredible creatures will be seen are on the big screen.

Works Cited

“Chondrichthyes.” Chondrichthyes. N.p., n.d. Web. 26 July 2014. <http://www.ucl.ac.uk/museums-static/obl4he/vertebratediversity/chondrichthyes.html>.

“Great White Sharks – Shark Pictures – Great White Facts – National Geographic.” National Geographic. N.p., n.d. Web. 26 July 2014. <http://animals.nationalgeographic.com/animals/fish/great-white-shark/>.

Janvier, Philippe. “Gnathostomata.” Tree of Life Web Project. N.p., n.d. Web. 26 July 2014. <http://tolweb.org/Gnathostomata/14843>.

“Shark Facts!.” Shark Facts RSS. N.p., n.d. Web. 26 July 2014. <http://sharkfacts.org/great-white-shark-facts/>.

“Sharks in Australian waters.” Department of the Environment. N.p., n.d. Web. 26 July 2014. <http://www.environment.gov.au/topics/marine/marine-species/sharks>.

Stevens, J. D. , R. Bonfil, N. K. Dulvy, and P. A. Walker. “The Effects of Fishing on Sharks, Rays, and Chimaeras (chondrichthyans), and the Implications for Marine Ecosystems.” ICES Journal of Marine Science 57.476-494 (2000): n. pag. The Effects of Fishing on Sharks, Rays, and Chimaeras (chondrichthyans), and the Implications for Marine Ecosystems. Web. 26 July 2014.

“Whale Sharks – Whale Shark Pictures – Whale Shark Facts – National Geographic.” National Geographic. N.p., n.d. Web. 26 July 2014. <http://animals.nationalgeographic.com/animals/fish/whale-shark/>.

Evolutionary History of Spiders

The class Arachnida includes not only spiders, but also ticks, scorpions, and mites, comprising over 640 families, 9000 genera, and 93,000 species within this class (Beavis, 2004). Spiders form the order Araneae, with over 110 families, 3,600 genera, and 39,000 species (Beavis, 2004). Forty species include the infamous Australian Funnel-Web spiders, such as the Sydney Funnel-Web (Atrax Robustus) and the Northern Tree Funnel-Web (Hadronyche formidabilis).

Spiders evolved on land about 400 million years ago shortly after Arachnids migrated to land with other arthropods (Gray, 2013). The earliest spider fossil is from 380 million years ago, when the earliest spiders (called the Mesothelae) had spinnerets under the middle of the abdomen, ate cockroaches and millipede, had parallel fangs, and lived on the ground floor (Gray, 2013). About 250 years ago, the Opisthothelae evolved to have spinnerets at the end of the abdomen like modern spiders, as well as learned to use silk as a safety dragline and catch prey (Gray, 2013). Aerial webs and modern prey-capture methods were adopted about 191 million years ago. While there has been a lack of spider fossils in Australia, other fossil records have shown that the modern spider is extremely similar to those from 30 million years ago (Gray, 2013).

Biogeographic & Phylogeographic History

The Atracinae comprise the Hexathelidae family, whereas the similar-looking “sister” species belong to the Dipluridae family (also known as the funnel-web tarantulas), both part of the spider superfamily Hexatheloidea. 174 species belong in this superfamily, found all over the world in the tropics of central and South America, Australia, Africa, and Central Asia (Hexathelidae). Yet how did these spiders migrate to these regions? The theory of plate tectonics may help explain the biogeography of the Hexathelidae and Dipluridae families. About 180 million years ago, Gondwana, the supercontinent that included present day South America, Africa, Australia, Antarctica, New Zealand, India, and Madagascar, began to break apart as the tectonic plates began to move (Gondwana). Africa and South America broke away first, then the rest, until the breakup of Australia and Antarctica.

*Biogeography of the Hexathelidae family (http://images.ala.org.au/store/7/2/4/b/d4b73a10-94ad-4648-84cd-48445f45b427/original)

*Biogeography of the Dipluridae family (http://fr.academic.ru/pictures/frwiki/68/Distribution.dipluridae.1.png)

The ancestor of the Hexathelidae family arose in East Antarctica in the early Jurassic period, then migrated into Africa, India, and Australia as Gondwana broke apart (Raven, 1980). Another ancestral sister group was the Pleisiothele, which migrated to Tasmania from Antarctica. The Pleisiothele group then crossed a land bridge from Tasmania to Australia and distributed into Laurasia, Africa, and India (Raven, 1980). The convergence of both of these ancestral spiders ultimately led to the Hexathelidae family.

Some species are often mistaken for Hexathelidae, including the trapdoor, mouse, and wolf spiders. These separate species build and reside in small holes lined with silk, but the difference lies in the fact that these spiders do not build a door for their burrows (Funnel-web spiders, 2013). Species from the Dipluridae family often fall into this category since they build funnel-shaped, messy webs (Szalay, 2013). The funnel-web tarantulas have a pair of vertical fangs, spinnerets, and range 3 to 15 millimeters in length. Their habitat includes living under logs, in the bark of trees, or underground, much like the Hexathelidae family (Dipluridae). The Sydney Funnel-Web (Atrax robustus) used to be categorized in the Dipluridae family before being moved to the Hexathelidae family in 1980 (Hexathelidea).

*Phylogeny showing clade encompassing the Hexathelidae family (http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0038753.g001&representation=PNG_L)

Species Diversity & Physical Characteristics

The Hexathelidae family is found is Australia, New Zealand, Asia, South America, the Mediterranean, and central Africa (Hexathelidea). The Atracinae subfamily is found in eastern Australia, with over 40 species in two genera: the Hadronyche and the Atrax (Funnel-web Spiders, 2013). These two genera include the two most poisonous spiders in the world–the Sydney Funnel-Web (Atrax robustus) and the Northern Tree Funnel-Web (Hadronyche formidabilis).

Atracinae range from 1 to 5 centimeters in length, typically brown or black with no unusual markings, hairy, and glossy. Their eyes are closely grouped, have shiny carapaces, short spines on lower lips, venom sacs and vertical fangs that do not cross each other (Funnel-web Spiders, 2013). Atracinae have a lateral pair of silk-spinning organs called spinnerets on the abdomen that are typically larger in species belonging to the Atrax genus than the Hadronyche (Funnel-web Spiders, 2013). The Atracinae is the only subfamily with numerous capsules on the labium, making it a monophyletic group (Raven 1980).

Females have shorter legs and a larger abdomen whereas the lighter males have two modified legs for mating that females lack (Funnel-web Spiders, 2013). Males have a spur on the second leg to hold the females fangs while mating (Sydney Funnel-web Spider).  Males live shorter lives, about 3 to 4 years, whereas some reports show that females can live up towards 20 years (Atrax robustus, 2007). The female lays hundreds of eggs in the burrow where the young spiders remain until they leave on their own. Female juveniles will leave the burrow after the first few molts to wait for a mate in their own burrow, while males will leave much later, about two  years after birth to search for a mate  (Funnel-Web Spider, 2012).

Another difference between male and female Atracinae  is more apparant with the infamous Sydney Funnel-Web (Atrax robustus). Only male Sydney Funnel-Webs are responsible for all recorded human deaths–this is due to the male’s venom that contains a unique toxin, robustoxin, that attacks the central nervous system (Funnel-web Spiders, 2013). This toxin is absent in females even though females have venom. The male venom is over five times more poisonous than that of the female Sydney Funnel-Web (Szalay, 2013). Males search at night for mates during the warmer months, which is another explanation for the higher percentage of bites coming from male Sydney Funnel-Web (Funnel-web Spiders, 2013).

Ecology

Australian funnel-web spiders (Atracinae) are found mostly in eastern Australia, from Tasmania to North Queensland (Funnel-web Spiders, 2013). Since Atracinae are prone to drying out, they typically dwell in wet, cool areas that include temperate forests, rainforests, and urban gardens (Funnel-web Spiders, 2013). Atracinae are found in highlands, such as in the hanging swamps of  the Blue Mountains, as well as in urban areas in New South Wales (Atrax robustus, 2007).

The funnel-web spider family is famous for its  method of survival–awaiting prey in a tunnel structure lined with silk  (Funnel-web Spiders, 2013). Funnel-web burrows are mainly found under logs, rocks, tree roots, forests, gardens, or decomposing trees (Atrax robustus, 2007). This structure leads to a small chamber, sometimes more than 30 centimeters deep, where the spider waits at night for something to set off the silk trip wires outside the burrow. When something comes across the trip wires, the funnel-web senses the vibrations and lunges out to attack its prey (Funnel-web Spiders, 2013). The Atracinae spider family is one of top predators–these spiders will not only eat small insects, but also prey on other spiders, lizards, and small frogs (Atrax robustus, 2007).

*Sydney Funnel-Web (Atrax robustus) in burrow (http://adm1370m-teamcarnivores.wikispaces.com/file/view/Funnel_web_spider10001.jpg/200789826/400×300/Funnel_web_spider10001.jpg)

However, some funnel-web spiders do not live in the ground or under wet logs. The Northern Tree Funnel-Web (Hadronyche formidabilis), arguably the most poisonous spider in the world, inhabits rot holes in trees, while others live in deadwood trees to prey on insects residing within the same tree (Funnel-web Spiders, 2013). The Southern Tree Funnel-Web (Hadronyche cerberea) live in Banksia, Casuarina, and eucalypts (Southern Tree Funnel-Web Spider, 2012).

*Northern Tree Funnel-Web (Hadronyche formidabilis) (http://www.adcpest.com.au/images/funnel-web-spider-pest-control-sydney.jpg)

The two main genera of Atracinae  include Atrax and Hadronyche. Both genera live sympatrically but favor different niches–the Atrax genus favors underground burrows, under logs or rocks, and sometimes gardens in urban areas (Beavis, 2004). Spiders belonging to the Hadronyche genus only burrow in decomposing logs. Therefore, spiders in the Hadronyche genus are habitat specialists and are highly sensitive to habitat changes. However,  Atrax spiders have a wider dispersal since they are able to live in various niches and thus must disperse to find new habitats to adapt (Beavis, 2004).

There is no current effort to preserve the Atracinae population because they are not an endangered species. However, as long as the Hadronyche spiders remain habitat specialists, it is ecologically important to preserve their habitats. The destruction or clearing of forests would likely negatively impact the Hadronyche population. Overall, it is important to recognize that even spiders should be protected.

Works Cited

Atrax robustus (Family Hexathelidae). (2007, February 7). Retrieved from Australian Government Department of the Environment Species Bank: (http://www.environment.gov.au/cgi-bin/species-bank/sbank-treatment.pl?id=75618).

Beavis, A. (2004). Phylogeography of Two Australian Species of Funnel Web Spider(Araneae: Mygalomorphae: Hexathelidae) in Tallaganda State Forest, New South Wales. Brisbane, Australia: United States Department of Agriculture.

Coddington, J. A. (2005). Phylogeny and Classification of Spiders. In D. Ubick, P. Paquin, P. Cushing, & V. Roth, Spiders of North America: an Identification Manual (pp. 18-24).

Dipluridae. (2013). Retrieved from World Heritage Encyclopedia: (http://worldheritage.org/articles/Dipluridae).

Funnel-web Spider. (2012, May 15). Retrieved from CSIRO Ecosystem Sciences: (http://www.csiro.au/Outcomes/Environment/Biodiversity/Funnelweb-Spider-Facts.aspx).

Funnel-web Spiders. (2013, May 6). Retrieved from Australian Museum: http://australianmuseum.net.au/funnel-web-spiders-group

Gondwana. (n.d.). Retrieved from Encyclopedia Brittanica.

Gray, D. M. (2013, May 6). Spider Origins. Retrieved from Australian Museum: (http://australianmuseum.net.au/Spider-origins).

Hexathelidea. (2013). Retrieved from World Heritage Encyclopedia: (http://worldheritage.org/articles/Hexatheloidea).

Raven, R. J. (1980). The Evolution and Biogeography of the Mygalomorph Spider Family Hexathelidae (Aranae, Chelicerata). Journal of Arachnology, 251-266.

Southern Tree Funnel-Web Spider. (2012, August 8). Retrieved from Australian Museum: (http://australianmuseum.net.au/image/Southern-Tree-Funnel-web-Spider/).

Sydney Funnel-Web Spider. (n.d.). Retrieved from Australian Reptile Park: (http://www.reptilepark.com.au/animalprofile.asp?pid=43&id=126).

Szalay, J. (2013, November 25). Funnel-Web Spiders: Families, Bites & Other Facts. Retrieved from Livescience: (http://www.livescience.com/41515-funnel-web-spiders.html).

Introduction

The ocean, vast and mysterious, has nurtured and sheltered one of the most fascinating mammal lineages on the planet—Sirenia. The sirenian order received their poetic name in light of the mythological sirens that lured sailors to misty shores. Their reclining posture when nursing and suckling their calves created an illusion of mermaids. Originating in Palaeocene era and reaching pinnacle diversity in Miocene, today the sirenian order contains only two surviving families, under which one species of genus dugong and three species of genus trichechus persist. Together they constitute the only extant herbivorous marine mammals.

Once broadly distributed, the mid-Miocene global cooling has restricted the sirenian order to tropical and sub-tropical regions. As habitat specialists that feed on coastal seagrass meadows, sirenians are susceptible to anthropogenic perturbations. The development and exploitation of coastal natural resources have casted profound impact on their status. As of the year 2000, all members of the order Sirenia are listed as vulnerable to extinction. Effective marine protected areas must be developed and current conservation legislation must be enforced to ensure the survival of the vanishing mermaid lineage.

Taxonomy

The order Sirenia is comprised of four families, Prorastomidae, Protosirenidae, Dugongidae and Trichechidae, two of which went extinct in Eocene era (Prorastomiade and Protosirenidae). They are herbivorous marine mammals that have undergone a separate convergent evolution with other large-bodied marine mammals in the Cetacean order. The current surviving genera include the following four species: dugong dugon (Dugong), trichechus manatus (North American manatee), trichechus inunguis (South American manatee), and trichechus senegalensis (west African manatee)

Phylogeny

Figure 1 A mammalia cladogram for living taxa (Shoshani and Mckenna)

Sirenia constitutes one of the five existent marine mammal clades. Although morphologically resembling the cetacean order, to which the seals and whales belong, the sirenian order actually evolved from an unrelated Paleocene mammal group known as the Tethytheria. Evolution has never failed to bear bountiful surprises—Sirenia shares a common phylogenic ancestor with the elephants (order Proboscidea).

Figure 2 Phylogenetic tree of marine mammals (Uhen)

Fossil evidence reveals that the earliest sirenians of the Prorastomid family were semi-aquatic quadrupeds that possessed limbs for terrestrial locomotion (Uhen, 519). They appeared to be estuarine mammals with diets resembling those of the modern trichechus. Meanwhile, the Protosirenidae—the sister family of Prorastomids—consisted of nearly exclusive seagrass feeders that resemble the present day dugong (Uhen, 519). Sirenians had become fully aquatic by the end of the Eocene, a period of high average global productivity and warm weather. The Dogongidae family arose from the Eocene as fully marine mammals with only vestigial hind limbs (Doming, 2). During this period, the sirenian tail flukes may have also diverged. Today, the trichechids possess broad, round tails while the dugongs have flukes that closely resemble those of modern cetaceans.

Figure 3 Simplified Phylogeny of the Sirenians (Domning)

The sirenian order achieved great species richness during the Eocene era, and continued diversification through the Oligocene. However, the Mid-Miocene global climate cooling resulted in significant reduction of the Earth’s tropical zone and caused progressive loss in sirenian diversity (Doming, 2). Around 3 million years ago, the closure of Central American Seaway further diminished the richness of this order by fragmenting their habitat and blocking genetic exchange between populations. The Dogonginae went locally extinct in the Atlantic basin and Caribbean ocean while the manatees remained. Today, remnants of the Dugongidae and the Trichechidae families persist in the tropical coastal zones.

Behavior, Physiology and Ecology

The intricate evolutionary history of the order Sirenia, albeit thought provoking, can only partially capture the fascination of this lineage. Their unique behavior, physiology and ecology invite greater interest. Sirenians are funny mammals exhibiting a “somnambulistic attitude…typified by a sluggish, peaceful and vegetarian nature” (Martin, 150). Scientifically speaking, the slow and nonchalant nature of sireanians reflects a relatively low nutrient level of their diets (Domning, 1). These calm creatures are largely nocturnal, spending the day asleep with only their nostrils emerging on the surface of water.

All sirenians have been tropical or sub-tropical dwellers apart from the hydrodamalis genera (Steller’s sea cow), which inhabited the North Pacific coasts but were hunted to extinction in the late 18^th century. Trichechids generally favor shallow lagoons and estuaries, whereas dugongs are completely marine. With their smooth, cylindrical bodies and unhurried motion, sirenians are largely defenseless against predators. Therefore, they carefully confine their habitats to waters “too shallow for the Killer Whale and sharks, and too saline for freshwater crocodiles” (Martin, 148).

As the only herbivorous marine mammals, sirenians could afford highly specialized dietary preferences. They feed primarily on angiosperms in the Hydrocharitaceae and Potaogetonaceae families, which encompass only about 50 species of plants (Doming, 2). Despite their stubborn fondness for the above-mentioned sea grasses, sirenians are not strictly vegetarians—when food resources become scarce, they have been known to feed on benthic invertebrates such as sea-pens, mussels and tunicates (Van Dyck and Strahan, 712).

Notably, during their long history of grazing on the shallow ocean floor, dugongs have developed corresponding physiological adaptations, such as dense, heavy skeletons that stabilize them on the sea floor while feeding, a downwardly deflected snout as well as broad prehensile upper lips for gathering seagrasses, and a massive stomach for storing large quantities of fiber (Van Duck and Strahan, 712).

Despite numerous shared traits, dugongs and trichechus exhibit subtle yet remarkable physiological and ecological differences. Dugongs are present in geographical regions between the 30 degree parallel, mainly inhabiting the warm waters of the Indian and southwestern Pacific Oceans. Their range spans at least 37 counties and territories. Regarding their physiology, the adults can reach a length of 8 to 10 feet and a weight up to 348 pounds. Dugongs have a large tail resembling the cetacean fluke, which can propel them at up to 22 kmh by broad up-and-down strokes. In undisturbed natural environment, dugongs exhibit gregarious social behavior, with large, strong old males acting as leaders of the herd and offering commands with specialized whistling sounds. In addition, dugongs also possess the fascinating capacity of cultivation grazing: they alter the species composition of seagrass meadows by intensive grazing, facilitating the growth of their favored fast growing pioneer seagrass species such as Halophila ovalis, while suppressing the slower growing dominant species such as Zostera capricorni (Gales, Hindell & Kirkwood, 386).

Figure 4 The known range of the dugong (Wikipedia)

In contrast with dugongs, trichechus are much more localized and restricted, inhabiting primarily warm marine and fresh waters of western Atlantic Ocean. Trichechus manatus (North American Manatee) can be found along the coast and coastal rivers of southeastern North America, the Caribbeans, and northeastern South America. They can reach a length of 6 to 11 feet and a weigh approximately 440 pounds. T.manatus’ favorite habitats are warm, turbid bays and muddy estuaries. Trichechus inunguis (South American manatee) inhabit the Amazon River and are restricted to fresh water. They constitute the smallest of all sirenians with a length under 6 feet and a weight under 440 pounds. Distinct from other trichechus species, the T.inunguis possesses iconic white breast patches and elongated flippers. The last member of the trichechus genus, Trichechus senegalensis (west African manatee) are found in tropical West Africa, both on the coast and in coastal rivers. Trichechus can be distinguished from dugongs by their tail shapes, which resembles that of the platypus. Furthermore, trichechus are remarkably more independent than dugongs though they may congregate during cold season migrations (Harrison and King, 165).

Figure 5 How to distinguish a dugong from a manatee

Conservation Status

In 2000, all sirenians were listed as vulnerable to extinct. Several factors may have contributed to their vulnerability. First of all, the sirenians’ life history has resulted in low intrinsic rates of population increase. Compared to other marine mammals, sirenians reach reproductive maturity relatively late, normally at age 6 to 10. Their long gestation period of 13 to 15 months coupled with their low birth rates and long suckling periods all work against rapid population expansion.

Secondly, sirenians’ highly specialized habitat and diet requirements have made them highly susceptible to habitat destruction. The 1992 Queensland Hervey Bay contamination exemplified the detrimental effect of dugongs’ habitat dependency. In this incidence, silt and other pollutants from flood runoff contaminated 1000 square kilometers of coastal Queensland seagrass meadows. Dugongs that used to depend on this habitat were denied of the previously rich feeding ground. Many died in Hervey Bay. The rest moved down to the cooler waters of coastal New South Wales and most died in emaciated conditions resulting from starvation.

Finally, in addition to biological and ecological factors, anthropogenic impact has long strained the sirenian populations around the world. Accidental tangling in fishing nets or traps constitutes a major cause of dugong mortality globally whereas vessel strikes in Florida cause alarming number of T.manatus deaths. Aboriginal overhunting continues to threaten the survival of dugong populations in Australia. Moreover, pollution of seawater may obstruct with the natural growth of seagrasses species favored by sirenians. Seagrass dieback can result from sedimentation, in which particles block sunlight and reduce seagrass productivity, or nutrient enrichment, whereby explosive epiphytic vegetations outcompete seagrasses. Last but not least, humans also cast indirect impacts on sirenians. For example, acoustic perturbation such as boat traffic can disturb sirenians’ regular feeding habits.

Among the order Sirenia, dugongs have the best prospect for survival because of their more globalized distribution than the trichechus although comprehensive conservation assessments suggest that dugongs are also threatened in many regions. Dugongs are “at risk of extinction in East Africa, India and Sri Lanka, Japan and Palau, [with uncertain prospects] in the Arabian Gulf, East and South-east Asia and Pacific Islands, and with reasonable prospects in the Red Sea (Gales, Hindell & Kirkwood, 393). With its vast marine protection areas and low coastal population density, Australia is recognized internationally as dugongs’ last stronghold. However, the urban coastal waters of Queensland and regions close to major Indigenous hunting communities still present great challenges.

What We Can Do

Three common themes have appeared in sirenian conservation proposals. First, governments need to establish more effective marine sanctuaries. Sanctuaries are the most effective if they are embedded in larger comprehensive conservation area such as the Great Barrier Reef. In addition, current protection legislation necessitates better enforcement. Seventeen countries have legislation that prevents killing sirenians, but most of them fail at implementation. Last but not least, governments should also engage the indigenous coastal communities in the conservation effort, raise their awareness in sustainable harvesting, and offer financial assistance if necessary.

Works Cited

Domning, Daryl P., and Hitoshi Furusawa. “Summary of Taxa and Distribution of Sirenia in the North Pacific Ocean.” Island Arc 3.4 (1994): 506-12. Web.

Domning, Daryl P. “Sirenia (Dugongs and Manatees).” Els.John Wiley & Sons, Ltd, 2001. Web.

Gales, Nick, Mark Hindell, and Roger Kirkwood, eds. Marine Mammals, Fisheries, Tourisms and Management Issues, Chapter 20 A Future for the Dugong? Marsh, Helene; Penrose, Helen; Eros, Carole. CSIRO Publishing, 2003. Print.

Harrison, Richard H., and Judith E. King. “Manatees and Dugongs.” Marine Mammals.Hutchinson & Co LTD, 1965. 150. Print.

Martin, Richard Mark. “Dugong and Manatees.” Mammals of the Oceans.Hutchinson Group (Australia) Pty Ltd, 1977. 147. Print.

Shoshani, Jeheskel, and Malcolm C. McKenna. “Higher Taxonomic Relationships among Extant Mammals Based on Morphology, with Selected Comparisons of Results from Molecular Data.” Molecular phylogenetics and evolution 9.3 (1998): 572-84. Web.

—. “Higher Taxonomic Relationships among Extant Mammals Based on Morphology, with Selected Comparisons of Results from Molecular Data.” Molecular phylogenetics and evolution 9.3 (1998): 572-84. Web.

Strahan, Ronald, ed. The Australian Museum Complete Book of Australian Mammals. Angus & Robertson Publishers, 1983. Print.

Van Dyck, Steve, and Ronald Strahan, eds. The Mammals of Australia, Order Sirenia. Third ed.Print.

Introduction

Over half of Australia’s 156 terrestrial snakes are venomous, making it the only continent with more venomous than non-venomous species (Williams, Wuster, & Fry, 2006). The most venomous land snake in the world, the inland taipan, is endemic to Australia (Australia Museum, 2014). Death adders, lowland copperheads, and red-bellied black snakes also inhabit the continent while sea snakes swim along its coasts. These snakes are all members of the family Elapidae, or the elapids.

The inland taipan, Oxyuranus scutellatus, is the world’s most venomous land snake.

Fixed Fangs, Venom, and Build

Elapids are characterized by a pair of hollow, fixed fangs that inject venom from the rear of the upper jaw into prey. The rostral location of the venom delivery apparatus differentiates elapids and sea snakes from other snakes. Usually, the venom of elapids is neurotoxic, but some species produce myotoxins, procoagulants, and anticoagulants. Most species are incapable of delivering medically significant bites to humans. Many Australian species remain unstudied, and their venom may become a resource for future drug development.

Image depicting a typical elapid’s fixed, hollow fangs and round pupils.

In general, elapids have smooth scales, slender bodies, and eyes with round pupils. Death adders are exceptions as some of these species are rough-scaled or cat-eyed (Shea, Shine, & Covacevich, 1993).

Species Diversity

Roughly 300 species in 61 genera are currently recognized as elapids (Keogh, 1998). Found primarily in the tropics and subtropics of Asia, Australia, Africa, and the Americas, elapids consist of big and small, colorful and dull, and banded and solid individuals. They range in length from 18 centimeter Drysdalia, crowned snakes, to the 5.6 meter Ophiophagus hannah, king cobra (JRank, 2014).  In the United States, the three species of native coral snake in the genera Micrurus and Micruroides are members of this family. These snakes are identified as venomous by the adage, “Red on yellow, kill a fellow.” Coral snakes in other parts of the world may be red and black, pink and blue, or have no banding at all (Szalay, 2014).

Eastern coral snake (Micrurus fulvius fulvius)

Blue Malaysian coral snake (Calliopsis bivirgatus)

Cobras, a group of snakes found in Africa and Asia, are elapids that spread their necks into hoods when threatened. The four species of mamba in Africa in the genus Dendroaspis are diurnal elapids. The black mamba is one of the fastest snakes in the world; it slithers up to 20 kilometers per hour (National Geographic Society, 2014).

Of the seven families of snakes found in Australia, Elapidae is the biggest and most diverse (Phillips, Brown, & Shine, 2003). The genus Oxyuranus consists of the inland taipan, coastal taipan, and the central ranges taipan. The central ranges taipan was only discovered in the last decade through mitochondrial DNA analysis; this reveals the lack of exploration of remote areas in Australia and underscores the importance of genetic analysis in studying speciation (Doughty et al., 2007). Taipans feed on rats and small mammals, and their highly neurotoxic venom paralyzes their victims’ nervous system and causes blood-clotting. Notechis is the genus of Australia’s tiger snakes. These snakes give birth to 20 to 30 live young and received their common name from their alternating dark and light bands. Acanthophis are the death adders found in Australia and New Guinea. Death adders resemble other adders with their stocky builds and triangular-shaped heads, but they are not true vipers as they do not have long, hinged fangs. Their similarities are due to convergent evolution. Australian copperheads of the genus Austrelaps are also not pit vipers nor close relatives to Agkistrodon contortrix, the American copperhead (Australian Museum, 2014).

Evolutionary History

In the Cretaceous period (about 120 million years ago), it is speculated that the first snakes evolved from lizards that swam in the oceans or burrowed. The disappearance of limbs was a result of a modification of the Hox genes, the genes that control limb morphogenesis (Gilbert, 2000). Although the fossil record is poor, it is known that modern snakes diversified during the Paleocene (roughly 55 million years ago).

This marine lizard is a transitional fossil between lizards and snakes.

In the Miocene (approximately 20 million years ago), Australian members of Elapidae arrived from Asia. Upon their arrival, an adaptive radiation occurred in which elapids filled various ecological niches. This rapid evolution makes it difficult to determine the relationships between genera and species. However, it is generally agreed upon that the hydrophiines, the largest group of sea snakes, evolved from terrestrial Australian elapids 10 to 15 million years ago and radiated into 60 species. The Australian and Melanesian terrestrial elapids and sea kraits are also members of the sea snake subfamily Hydrophiinae. Their origin is Asian. Old world elapids found in Africa and Asia, like the cobras and mambas, belong to the subfamily Elapinae. It is suspected that their origin is Asian, African, or Afro-Asian. The Hydrophiinae and Elapinae combine to form the large family Elapidae (Keogh, 1998).

Two possible phylogenies depicting the relationship between terrestrial elapids and sea snakes.

Evidence of the land bridge between New Guinea and Australia during the Pleistocene and even the Holocene (1 million years ago to 10,000 years ago) is supported by the sharing of several elapid species, such as Furina tristis, the brown-headed snake, Oxyuranus scutellatus, the coastal taipan, Pseudechis australis, the common king brown, Rhinoplocephalus boschmai, the Carpentaria whip snake,and R. nigrostriatus, the Australian black-striped snake. When low precipitation and freezing lowered sea levels, these species were able to migrate north and south and vice versa (Shea, Shine, & Covacevich, 1993).

Ecology

Elapids mate in the autumn or spring, or sometimes both. Most elapids lay eggs (oviparous) although a few Australian species, such as the tiger and sea snakes, bear live young (ovoviviparous). Parental care for eggs or young has only been observed in king cobras. These snakes remain with their eggs to provide protection (JRank, 2014).

Depending on the species, terrestrial elapids may eat small mammals, birds, fishes, lizards, frogs, or other snakes. Some have specialized diets while others are less particular. North American coral snakes, for example, prefer dining on small lizards but will also eat frogs and other snakes (2014). Sea snakes munch on fishes, squids, or eels in coral reefs.

Elapids actively hunt, striking and biting their prey with their fangs. These fangs release venom that quickly slows the victim’s heartbeat, making it easier to eat. A unique adaptation of Australian death adders is to wriggle the tip of the tail in the air to fool prey into thinking a tasty grub is waiting to be eaten. When the prey gets close, the death adder strikes (Australian Museum, 2014).

Check out this death adder‘s grub-like tail!

Larger Australian elapids are generally diurnal, basking in the sun during warm days, while smaller Australian elapids are crepuscular or nocturnal, relying on transferred heat from objects and protected shelters for warmth. The activity of elapids varies by season. At the Top End, elapids are particularly active in the summer months when heavy precipitation occurs. In southern Australia, elapids may overwinter beneath superficial shelter and emerge during sunny, warm days (Shea, Shine, & Covacevich, 1993).

Elapids are suited to a variety of niches. Deserts, grasslands, woodlands, rainforests, and oceans make up a few of their habitats. Some elapids are found in rocky outcrops, like the Australian Hoplocephalus bungaroides, the broad-headed snake, while others have become specialized burrowers in arid environments, such as Ogmodon vitianus, the Fiji snake (Department of the Environment, 2014).

Three particularly hot spots for elapids exist in Australia: south-western Western Australia, south-eastern South Australia, and the region including eastern Queensland and extreme north-eastern New South Wales. These areas are rich in habitat diversity, providing elapids with more chances to specialize. Mixed vegetation thrives in the south-eastern Queensland region, and its subtropical climate supports animals adapted to both hot and cold weather (Shea, Shine, & Covacevich, 1993).

 Conservation Status

Herpetofauna include some of the most imperiled species on Earth. A combination of toxins, global warming, disease, non-native predators, over collection, and habitat destruction contribute to their declining numbers (Center for Biological Diversity, 2014). In Australia, several terrestrial elapids are listed as vulnerable. The broad-headed snake faces fox and cat predation. In addition, its range covers the populated Sydney area in New South Wales, putting its habitat directly at risk of disturbance and development by humans. Furina dunmalli, Dunmall’s snake, has lost habitat from mining, agricultural activities, and the draining of swamps. It likes brushy, wooded areas, and fallen timber and ground litter have become difficult to find. Invasive predatory and plant species threaten this snake, too. Denisonia maculata, the ornamental snake, is listed as vulnerable as a result of land clearing and the cane toad (Department of the Environment, 2014). The toxins in the paratoid glands of this invasive toad are enough to kill some snakes that mistake them for tasty meals (Phillips, Brown, & Shine, 2003).

Unfortunately, water is not a safe haven for elapids, either. In Western Australia, Aipysurus apraefrontalis, short-nosed, and A. foliosquama, leaf-scaled, sea snakes are restricted to coral reefs. They were abundant in the Ashmore and Hibernia Reefs during the 1970s and have since mysteriously declined, although their habitats are intact. Nine other species of sea snake have disappeared from these reefs in the last fifteen years. Possible causes include sedimentation, changes in salinity, and air-gunning during seismic surveys for oil and gas (Sanders, 2013).

Increased awareness and education can help erase the negative attitudes many people harbor toward snakes. The majority of species are quite reclusive and shy, and respect is all that is required to appreciate snakes and stay safe. These animals fill ecological roles as predators, and conserving their habitat and understanding their biology is crucial for their continued survival.

Me happily holding a non-venomous smooth green snake. Snakes rock!

 Works Cited

Australian Museum. 2014. Search the Site. Retrieved from http://australianmuseum.net.au

Center for Biological Diversity. 2014. The Amphibian and Reptile Extinction Crisis. Retrieved from http://www.biologicaldiversity.org/campaigns/amphibian_conservation/

Department of the Environment. 2014. Species Profile and Threats Database. Retrieved from http://www.environment.gov.au/sprat

Doughty et al. 2007. A New Species of Taipan (Elapidae: Oxyuranus) from Central Australia.       Zootaxa, 1422: 45-58.

Gilbert, S. F. 2000. Hox Genes: Descent with Modification. In Developmental Biology Sixth         Edition. U.S.

JRank. 2014. Kraits Cobras Sea Snakes and Relatives: Elapidae. Retrieved from Net Industries: http://animals.jrank.org/pages/3897/Cobras-Kraits-Sea-Snakes-Relatives-Elapidae.html

Keogh, J. S. 1998. Molecular Phylogeny of Elapid Snakes and a Consideration of Their Biogeographic History. Biological Journal of the Linnean Society, 63: 177-203.

National Geographic Society. 2014. Black Mamba. Retrieved from http://animals.nationalgeographic.com/animals/reptiles/black-mamba/?rptregcta=reg_free_np&rptregcampaign=20131016_rw_membership_r1p_intl_dr_w#

Phillips, B. L., Brown, G. P., & Shine, R. 2003. Assessing the Potential Impact of Cane Toads on Australian Snakes. Conservation Biology, 17: 1738-1747.

Sanders, K. 2013, February 21. Australian Endangered Species: Sea Snakes. The Conversation.

Shea, G., Shine, R., & Covacevich, J. 1993. Fauna of Australia: Family Elapidae. In G. J. Ross, P. L. Beesley, & C. G. Glasby, Volume 2A Amphibia and Reptilia. Canberra.

Szalay, J. 2014, March 7. Coral Sankes: Colors, Bites, Farts, and Facts. Retrieved from Live Science: http://www.livescience.com/43938-coral-snakes-colors-bites-farts-facts.html

Williams, D., Wuster, W., & Fry, B. G. 2006. The Good, the Bad, and the Ugly: Australian Snake Taxonomists and a History of the Taxonomy of Australia’s Venomous Snakes. Toxicon, 48: 919-930.

Doing Things the Aussie Way

The first couple days of our month long journey through Australia started off in the capital city of the Northern Territory, Darwin. Darwin has a population of about 130,000 and is 112 km ² which is roughly half the size of Durham. It’s a town with one main strip which, luckily, we are in walking distance of. If there’s one thing we can be certain of, it’s that we will be doing a lot of walking in this country. Australia is approximately the same size of the continental United States but has significantly less people. In fact, there are only two people per square kilometer on average! When looking at the geography of Australia, it’s quite clear why many places are uninhabitable. About 20% of the country is strictly desert and 70% is considered arid, semi-arid or desert. In the “Top End” where we are, it’s winter time, but we are in shorts and t shirts since it’s about 28 degrees outside. Well, 28 degrees Celsius that is. In Australia, like most other countries in the world, they use the International System of Units commonly known and SI. This is very noticeable when looking at speed limits and gas prices, and, of course, everyone gives you strange looks when you say “It’s 100 degrees outside!” It’s pretty clear that they do things a bit differently here, but it’s a great thing to banter about. Australians are fairly easy going people who generally love to joke around and poke fun at each other. Unlike the work oriented life of Americans, when 5 O’clock rolls around, work is completely over. They have a ‘No Ts’ saying here: “Not today, not tomorrow, not on Tuesday, not on Thursday.” Basically, relaxing is essential to their daily lives. One of the first Aussies we met as a group goes by Nick, who is a dean at the University of New South Wales. He’s helping us get acquainted with our new surroundings and helpings us get where we need to go. One of the first things he talked to us about is Jet Lag which most of us have. Australia is fourteen hours ahead of the United States so it took us a while to get our clocks in sync with theirs. We were exhausted around 8pm and most of us woke up around 4am. Thankfully most of us were solid within three days and really enjoyed our time in Darwin. Here are a few places we went.

Northern Territory Museum

Here we learned a lot about aboriginals and their artwork as well as some of the species that live in the Northern Territory. I found the aboriginal section of the museum very interesting because I love to learn about natives and their cultures. One of the quotes really got my attention because previous to this trip I was reading a book that discussed the relationship between science and religion, (more specifically Darwinism and Christianity) and the author had a place in the book where he said that the universe was created for us to discover. Here’s the quote that captured the essence of that statement.

“I am not painting for pleasure; there is meaning, knowledge and power. This is the earthly painting for the creation and for the land story. The land is not empty, the land is full of knowledge, full of story, full of goodness, full of energy, full of power.” –Wandjuk Marika 1995

There was also an exhibit on Alfred Wallace who we learned developed the theory of evolution around the same time as Darwin by studying island biogeography which is basically what our course is about. In addition to that, there was a wealth of information about animals in the Northern Territory. There were spiders, turtles, wallabies, lizards, and even the largest species of sea snail in the world! There was also a stuffed saltwater crocodile named Sweetheart. She weighed 780 kg, was 5.1 meters long and her snout length was 2.4 meters long. I think it’s unfortunate that such a massive and beautiful creature is stuffed and put on display, but I do have to say that he’s one of the last things I want to be in the water with.

Darwin Botanical Gardens

While we were there we saw Red-Tailed Black Cockatoos which are a rare species now and we even ate green ants! Almost everyone in the group gave it a try and we all agreed that they taste like sour apples. Liz, told us about their nests and how they make them. The ants are arborial meaning that they live in trees. Their nests are made out of leaves and a sort of mucus that their larvae secrete. They look a lot like a small package made out of leaves and the way these ants build their nests are quite fascinating. One of the ants uses its front and back legs to hold two leaves together while another takes the larvae and rubs it along the edges of the leaves to make it sticky. Then a third ant uses its front legs to sort of weld the mucus into place. The inside of this nest, surprisingly, isn’t that intricate-it’s basically hollow and filled with ants. We also saw a mango tree, Bayobab trees (you may have heard it from The Little Prince) and we even saw a huge wasp like insect dragging an enormous spider! Speaking of spiders, Australia has many deadly ones and for a  list of deadly animals check out my blog post about them.

Welcome to the Land Down Under 🙂

Today was our first full-day excursion! Our destination? Litchfield National Park. Our goal? Learn about termites.

Nice.

Although the termite isn’t the most glamorous animal in Australia, learning about them was actually a lot cooler than I thought it would be. That isn’t really saying much though, because my expectations were pretty low to begin with.

As we were driving into the national park, we started to see these tall, sand-colored, oddly shaped, boulder-like things popping up between the trees.

“How did those rocks get there?” one of my classmates asked. “Those aren’t rocks,” Rytas replied ominously.

That’s right. These monsters are termite mounds:In case you just cringed, here’s a comforting thought: 3/4 of the mound is actually underground. That’s right, this is only 1/4 of their home. Oh wait…that just made it worse, didn’t it?

Ranging from little bumps in the ground to 6 meter tall “cathedrals”, the mounds are pillars of soil and cellulose held together via salivary excretions from the termites. They are built specifically to serve as termite mansions, but they often house other insects as well. They grow to this size because when the ground floods in the wet season the termites need a safe place to hide out.

Termites, like ants, are social insects. Inside the nests live termites at all stages of life. The queen rules over her minions: workers, soldiers, larvae, nymphs, and alates. The queen gives birth to all the larvae, who eventually grow into nymphs and go through the molting process. Some of them become alates (termites capable of reproduction), and fly off to start their own colonies. Others become workers; workers are blind, sexless drones that seek out food (it’s very robotic and kind of freaky). Soldier termites protect the nest, occasionally injecting venom into their enemies. In addition to their complex caste system, termites are voracious herbivores – supposedly 70% of all eucalyptus stems are hollow from termite consumption. That fact is either impressive or horrifying, depending on how you look at it.

One cool thing about Australian termites is how they’ve adapted to their environment. First of all, since bush-fires are so common, these termites (and their homes) are virtually fire-resistant. Another cool thing is that the same species of termite builds mounds of different shape depending on the type of land it lives on. If it lives in the dry bush, the termite builds the buttressed, cathedral-like mound in the picture above. But, if it lives in a grassy wetland (often times adjacent to the dryland), it builds a “magnetic mound”. These mounds are flat and long, and look kind of like giant gravestones. The weird thing is, they are all perfectly aligned North/South, so that they can catch the most sun. Pretty fancy, I know. (Scientists think that their instinct is mostly environmental, although some studies may show that the termites can sense the magnetism of the earth, which is pretty crazy)

Magnetic Mounds: We eventually left the termites to do what they do and moved on to Florence Falls for lunch. Lunch was a nice break from the termite talk, complete with Australian flavored potato chips (honey soy chicken?!?! What?!!?). But, what came after lunch was even better than termites AND food: swimming!

We went on a short hike to the waterfall, which was stunning (as are most things in Australia, I am quickly learning)The water was pretty cold, but very refreshing. A few of us scrambled up 5-10 feet on the red, slippery rocks in between the two falls and took some pictures. Once we were up there, we were met with a small issue: climbing back down. The rocks were a little too slippery to go back the way we came, but a brave little 7 year old showed us how to slide off them, introducing us to the most natural/painful water slide I’ve ever had the pleasure of going down.

Afterwards, Allison and Maddy decided to free-climb up the cliff to the right of the falls. When they got up there, they faced the same problem as before: getting down. Unfortunately, there was no water slide this time. They had 2 choices: die on top of the cliff, or jump. So, they blatantly ignored the warning sign advising swimmers not to jump or dive (because death had actually occurred in the past), and they both plummeted 30 or so feet back into the water.

They both survived. So, naturally, I had to do it too. Evan and I followed their path up the cliff and plunged into the water after them. To be perfectly honest, I thought the climb was much scarier than the jump, but that might just be the diver in me talking.

The few. The brave. The cliff-jumpers.

After swimming we went back to the apartments and then headed down to Mindil Beach for the weekly Sunset Market. It was like a mix between a state fair and a flea market, except the food wasn’t quite as fried and the goods were all Australia-themed. Stands selling boomerangs, seafood, and exotic smoothies were peppered by the occasional fire-breather, or aboriginal didjeridu player. It was very cool.

At the market I had a mango smoothie and some fried rice and paid way too much for both. Then I watched the sunset and splurged on a beautiful tapestry that probably isn’t Australian in origin and also probably won’t fit in my dorm. Oh well. It was worth it. Call it a belated birthday gift to myself? Yeah, we’ll go with that.

The sunset was amazing, once again. Check it out: And with that, we went back home to Alatai Apartments and crashed. Here’s to another exhausting, fun-filled day in Darwin!