Wedge-Tailed Eagle (Aquila audax)

I picked today’s animal because lately I’ve had a hankering to draw some kind of claw or talon. When I think of impressive talons, I immediately think of eagles, so I searched around until I found a suitable candidate. And lo! The wedge-tailed eagle popped up, and I couldn’t have found a better bird to draw and to write about.

The wedge-tailed eagle is found in Australia, so I’m shocked it’s not venomous. There are also populations in New Guinea and Indonesia. Wedge-tailed eagles are fairly flexible about where they live: they can be found in almost all habitats in Australia, including rainforest, forests, savanna and mountainous areas. Though they can be found in a wide variety of habitats, they do tend to prefer more open areas, such as woodlands and grasslands.

Aquila_audax_-Symbio_Wildlife_Park,_New_South_Wales,_Australia_-head-8a

An angry-looking wedge-tailed eagle. Image credit: Susan via Wikipedia

Wedge-tailed eagles are big, and are in fact the largest birds of prey in Australia. Like all raptor species, females are bigger than males, measuring up to 2.84 m in wingspan. This is the largest wingspan recorded for a species of eagle. This does not classify wedge-tailed eagles as the largest species in the world, however. Their wings and tails are long for their body size, and so a number of other eagle species outweigh wedge-tailed eagles.

These eagles get their name from the long, wedge-shaped tail that is unique to their species. They are dark brown or black, with reddish brown feathers under their wings and around their neck and shoulders. Young eagles are golden brown or reddish brown, and darken as they age.

Wedge_tailed_eagle_in_flight04

A great picture showing the wedge-tailed eagle’s wedged tail. Image credit: fir0002 via Wikipedia

Wedge-tailed eagles are gliders, soaring at very high heights for hours. They will often be found soaring at altitiudes of over 1,800 m. They spend most of their time perching and surveying their lands. These birds aggressively defend their territory, soaring in arcs and diving to advertise their ownership. If an unfortunate bird does enter a wedge-tailed eagle’s home range, the eagle will dive and attack the intruder. They will also attack hang gliders and paragliders that enter their territory, which is presumably an unsettling experience for the gliders.

Wedge-tailed eagles hunt and scavenge for their food. Their main source of prey are rabbits and hares — both of which are introduced species. Eagles will also hunt foxes, cats, wallabies, kangaroos, koalas and other birds. On rare occasions, wedge-tailed eagles will work together to hunt larger prey, such as red kangaroos. They are known to chase goats off hillsides so that they injure themselves, and will isolate weaker animals from flocks for easy hunting. Wedge-tailed eagles are adaptable, and are not above scavenging. They will chase crows away from carrion and are often seen feeding on roadkill.

eagle talons

My drawing of wedge-tailed eagle talons. It’s done in charcoal, which I rarely use, but will probably start doing more of, because I really enjoyed drawing this!

Like many birds, wedge-tailed eagles are monogamous. They choose one partner for life, and will stick together until one of the pair dies. Breeding season occurs from June to August. The birds build a nest from sticks and leaves, usually in trees or on cliffs or hillsides. The nests are used from year to year, and can reach sizes of 1.8 m wide and 3 m deep after years of use.

Females lay one to three eggs in the nest, which do not hatch simultaneously. This means that the first chick to hatch has an advantage over its siblings. When food is scarce, the elder chick will often kill the other young, by outcompeting them or through a direct attack. The young fledge at 75 to 95 days of age, and are dependent on their parents for another three to five months. Sexual maturity is reached at about three years of age, but eagles usually will not mate until they have their adult plumage, which occurs around six years of age.

Thankfully this majestic species is not currently threatened, though the Tasmanian subspecies is considered to be endangered. As adults, wedge-tailed eagles have no natural predators, but they were once hunted by humans who wanted to protect their livestock. It has since been shown that wedge-tailed eagles do not have a large impact on livestock populations, so farmers can now leave them alone, which is fabulous news for both famers and the eagles.

Cover image credit: fir0002 via Wikipedia

Green Tree Python (Morelia viridis)

I definitely chose today’s animal for its looks. I was out of the country for the past two weeks for work, and couldn’t bring much with me. So I grabbed my smallest sketchbook and brought only one pen — one of those clicky ones that has multiple colours. All I had to work with was red, green, blue and black. And so I picked a snake that was mostly green, hoping I could make some kind of passable art with the supplies I had brought.

The snake I chose to draw was the green tree python, a snake that is found in Australia, Indonesia, and New Guinea. These snakes are aptly named, as they are green and like to live in trees. They are found in tropical rainforests, generally staying at elevations between sea level and 2000m. Younger snakes tend to stay around the edges of the forest or in canopy gaps, while adults are perfectly comfortable in closed-canopy forests.

Green tree python

My drawing of a green tree python’s eye. I think it turned out pretty well!

Green tree pythons can get pretty big, with the average length being 1.5 meters, though snakes of up to 2.2 meters have been recorded. They are long and thin, with a well-defined head. Green tree pythons are really beautiful snakes: they are bright green with white scales forming a patterned line down their backs. Juvenile snakes are easily distinguished from adults, as they are either bright yellow or red.

As I mentioned, green tree pythons are quite fond of trees. In fact, they are the most arboreal python in the world. Their long tails are prehensile, which helps them climb and navigate their forested habitat. Tree pythons have a very distinct resting posture, where they throw a few coils over a branch and then sit in a saddle position with their heads resting in the middle.

Morelia-viridis

A green tree python resting in a typical ‘saddle’ position. Image credit: Micha L. Rieser via Wikipedia

This is quite distinct from the pythons’ hunting posture. When green tree pythons are looking for prey, they extend the front part of the their bodies, ready to strike at any prey that wanders by. Snakes change between resting and hunting postures at dawn or dusk, to stay camouflaged.

Green tree snakes are carnivorous, feeding on small reptiles, amphibians and mammals. They kill their prey by constriction, and do not have any venom. Adults are nocturnal, feeding on the larger animals that emerge at night. Juvenile snakes come out during the day, and feed mainly on small reptiles. As ambush predators, green tree snakes do not actively search for prey, and don’t move very much. They are so lazy they will use the same ambush site for up to two weeks.

This strategy is quite useful for green tree snakes, as it helps them hide from predators. As adults, their green colouration and lack of movement makes them blend in to the leafy trees. Juveniles are also well camouflaged — yellow snakes camouflage well in forest edges, while brick-red juveniles blend in with tree trunks and other non-leafy backgrounds.

JBR_7494

A juvenile of the brick-red variety. Image credit: Johnkentucky via Wikipedia

We don’t know a whole lot about green tree python reproduction in the wild, as breeding has never been recorded in their natural habitat. What we do know we have learned from captive populations. Females lay 1 to 25 eggs, which she broods and protects for almost two months. The eggs hatch at the start of the wet season, in November. The hatchlings are about 30 cm long, and reach sexual maturity between two and four years of age.

Green tree pythons are popular snakes in captivity, and tend to do quite well once their needs are met. Because of their popularity, their population is under pressure from hunting for the pet trade. There are captive breeding programs however, so if you want to get a green tree python, just make sure you source it from a captive breeder!

Cover image credit: Mattstone911 via Wikipedia

Common Snake-Necked Turtle (Chelodina longicollis)

Turtles are pretty cute, but some are cuter than others. Today’s animal, the eastern long-necked turtle, or common snake-necked turtle, is a bit funny looking. Still, they are cute in their own way, just not as cute as some other turtles I’ve seen.

Common snake-necked turtles live in Australia, in the southeastern part of the country. They enjoy water, usually living in somewhat-stagnant waters, such as swamps or wetlands. These turtles generally hide out at the bottom of the waters they inhabit, coming to the surface to bask in the wonderful warmth of the sun. If they are unlucky enough to live in a pond or swamp that dries up, the turtles will look for a new home, or will burrow into forest floors to stay wet until conditions improve.

tumblr_inline_nw9wpex9Yz1tbvxo1_1280

A nice perspective shot showing a long-necked turtle’s long neck. Image source 

 

Long-necked turtles, of course, have long necks. But how long is long? Well, common snake-necked turtles don’t grow super large, reaching total lengths of 25 cm. So their necks are not too large in an absolute sense, but they are relatively long, being about 60% percent of the length of the turtles’ shells. The turtles are dark grey or brown, with a brown or black shell with fun, turtle-like patterns on it.

Snake-necked turtles are not picky eaters, eating fish, invertebrates, tadpoles, crustaceans and even carrion. They hunt by ambushing their prey, using their long necks to strike at their victims. Snake-necked turtles are also victims of predation, falling prey to red foxes, water rats, ravens, eagles, and dingos. When they are threatened, snake-necked turtles will emit a gross, smelly fluid from their musk glands. They will also snap at any predator that comes too close, though this doesn’t seem to be highly effective.

Digital StillCamera

Long-neck turtles will also pull their heads into their shells for protection, though not the way normal turtles do. These turtles are side neck turtles, meaning they pull their heads in sideways, not straight back. Image source: Wikipedia

Mating in snake-necked turtles happens in spring, from September to October. Males win over females with a relatively simple display involving head bobbing and intimate touching. Females lay their eggs near water, and lay 8-24 eggs. These hatch in five months, from January to April. Hatchlings grow slowly, reaching sexual maturity between 7 and 12 years of age.

Eastern long-necked turtles are currently not threatened, though other species of long-necked turtles are. I guess if the word ‘common’ is in your name you should probably be fairly abundant. So well done, common snake-necked turtles!

Cover image source: CSIRO via Wikipedia

Sydney Funnel-Web Spider (Atrax robustus)

It’s been quite some time since I tortured myself by blogging about a spider. So now it’s time to jump right back in with a particularly terrifying one: the Sydney funnel-web spider. Ever since I was a child these spiders literally gave me nightmares – I remember one particularly nasty dream where I kept tripping in the spiders’ burrows.

There are thirty-five species of funnel-web spider, but the Sydney funnel-web is particularly deadly. As its name implies, the Sydney funnel-web lives in and around the city of Sydney, Australia. Funnel-web spiders live in burrows, usually in soil with high humidity and low temperatures. I’m used to looking for spiders in trees and doorways, but something about them also being on the ground gives me the creeps.

These spiders are not just tiny critters that you can ignore — they have body lengths of one to five centimetres, with leg lengths of six to seven centimetres. Any spider is too big, but one that’s 12 cm in diameter is definitely right out. Sydney funnel-webs are usually black or dark brown, and have a somewhat glossy appearance.

PICT0660

A female spider in her burrow. Image source

Funnel-web burrows are creepy, web-lined things. The spiders deposit webs on the ground radiating from the burrows’ mouths, and it is these silken strands that help funnel-web spiders catch their prey. Insects and other small creatures have a difficult time moving on the spiders’ slippery webs, but the funnel-webs have no trouble at all. So the spiders rush out and bite the hapless victims, injecting their venom into their prey.

Sydney funnel-web spiders have very powerful venom, but it doesn’t affect all animals equally. Unfortunately the venom is particularly effective against primates, including people. Though the venom can be deadly, there have been no recorded human deaths from the bite of a funnel-web spider since the development of an antivenin.

Atrax_robustus

A funnel-web spider warning away a predator. If you see this posture, STAY AWAY! Just look at those fangs… Image credit: Tirin via Wikipedia

Sydney funnel-webs are so dangerous to people because, unlike many other venomous animals, funnel-web spiders are very aggressive and will readily attack. Males wander away from their burrows to search for females to mate with, and so often run into unsuspecting people on the way. Male spiders also have more potent venom than females, so watch out for them if you’re in Sydney.

I am scared of spiders because they have way too many legs and way too many eyes, not because some species have the potential to kill me. Still, there’s an extra element of terror when spiders are highly aggressive, nasty killers. So stay away from any burrows you see in Australia.

Longnose Sawshark (Pristiophorus cirratus)

I don’t think it would be very much fun to have a saw as a mouth, but at least one animal in this world thought it was a good idea. It would make sense that this animal is a shark. After all, sharks try their best to be as terrifying as possible, and what’s more intimidating than a shark with a saw on its face?

Longnose sawsharks live in the waters around Australia, in the Indian and Pacific Oceans. They can be found in both coastal areas and in the open ocean, though they prefer spaces with sandy bottoms. Sawsharks are usually found at depths below 40m.

longnose sawshark-dante vs nature-dantania-blogspot-com

These sharks look so ridiculous… Image source: http://dantania.blogspot.ca/2013/08/dante-vs-nature-27.html

The most characteristic and recognizable feature of the sawshark is its giant snout. Sawsharks can grow to be 1.37 meters long, and their snouts can make up 30% of that length. That’s a pretty big nose! About halfway down this impressive noggin are two barbels, which help the shark feel its way around the ocean. The sawlike appearance of the sharks’ noses is due to their protruding teeth, which are arranged in an alternating long and short pattern. Sawsharks are a boring combination of yellow, grey, and brown. Though these colours aren’t very flashy, they do help the sharks blend in with the ocean floor, giving them some protection against predators.

Those vicious and undoubtedly strange snouts do serve a purpose — they are used for hunting. The sharks swim close to the ocean floor, their barbels sensing the sandy bottom, and their ampullae of Lorenzini detecting any electric fields made by nearby prey. Once they have found a tasty morsel, the sharks slam it with their snouts, immobilizing the victim.

6798338

Another great picture of a longnose sawshark and it’s impressive nose. Image source: http://www.nhmsharksandrays.co.uk/the-fish.html

Longnose sawsharks are slightly unusual for sharks in that they often form schools. They breed every two years, and give birth to 3-22 live young. You might think that it would be incredibly painful to give birth to sharks that have rows of sharp teeth sticking out of their snouts, and you would be right. Thankfully, sawsharks have a solution to this — when the young are born their teeth are folded in, and only straighten out after they’ve left their mother’s belly.

The conservation story of the longnose sawshark is a happy one. They were once classified as Near Threatened, but have recently been downgraded to Least Concern. Protection from fishing has helped these sharks tremendously, and these days they seem to be doing quite well.

Geographic Cone Snail (Conus geographus)

You know how I’ve often said to steer clear of Australia? Well here’s another very good reason to stay out of there. Australia (and the waters around it) is home to the world’s most venomous snail (yes, snail). The geographic cone snail has extremely potent venom, which is capable of killing an adult human.

As I mentioned, cone snails are found in the waters around Australia. They are also found in other areas of the Indo-Pacific, in tropical and subtropical waters, as well as the Red Sea. They are generally found in and around coral reefs, in shallow, warm waters.

IL2-013 Geographic Cone, Conus geographus

A nice picture of a geographic cone snail. You wouldn’t think such a creature would be one of the most venomous animals in the world, but it is. Image source

Geographic cone snails have beautiful outer shells that are coveted by collectors. Their shells can grow to be ten to fifteen centimetres long, and are covered in brown and white patterns, often with some pink or red thrown in. The snails themselves mainly consist of a foot, eyestalks, a proboscis that is used to swallow prey, and a siphon that they use to detect chemicals in the environment.

The most dangerous part of cone snails is a harpoon-like tooth housed in the snails’ proboscises. The snails use this tooth to hunt prey, usually waving their proboscis like a lure and stabbing any fish foolish enough to get too close. They then swallow the fish, regurgitating the bones a few days later.

Cone_géographique

The dangerous part comes from what the cone snails inject into their poor victims. A lovely melange of toxic compounds make up the cone snails’ venom, which is estimated to be the most toxic venom in the world. There’s enough venom in a single cone snail sting to kill fifteen people. And there is no antivenin for cone snail stings, so these guys are especially deadly. The only treatment involves keeping the victim alive (via artificial respiration and other fun things) until the toxins have left the body.

There is good news, though (for we humans, not for the cone snails). Within the vast array of compounds present in cone snail venom are some that have potential in medicine, particularly as very potent and non-addictive painkillers. But still, these snails are horribly deadly, so be wary of any pretty shells you see in Australia!