How weird are platypuses? Why does Saudi Arabia import camels from Australia? Why do kangaroos have pouches? How scary are bulldog ants?
When European naturalists first encountered the platypus, they thought it was an elaborate hoax. It had the bill of a duck, the feet of an otter and the tail of a beaver. But it was even weirder than that. The platypus is one of the few mammals (together with the rest of the monotremes, which include 4 species of echidnas) that don’t give birth. They lay eggs instead. That’s right, eggs. You can imagine the explorers’ confusion. Someone had to be playing a prank.
Platypuses are also on the very short list of venomous mammals, together with the vampire bat (not sparkly), the Eurasian water shrew and a couple of others (complete list here). They also don’t hunt with sight or smell, but with electroreception. Electroreception is the ability to detect the tiny electrical fields generated by muscle contraction. When they dive to feed, they close their eyes, nose and ears, only relying on this peculiar ability, which is shared only with echidnas and one species of dolphin.
Saudi Arabia imports camels from Australia! First introduced down under in the 19th century, feral camels are now quite a big issue in Australia. There are at least 500 thousand, if not a million, of them roaming the vast expanse of the continent. In 2009, ABC news reported that 6000 camels were to be culled as they had been terrorising a small community in Docker River. Thirsty camels would break into houses in search of water.
The camels imported from Australia are used for camel racing, a popular sport in the arabic peninsula. Traditionally, child jockeys were used due to their light weight. However, the UAE and Qatar have banned their use, and lately robot jockeys have been introduced.
Now picture a camel. I’m quite certain that you pictured it in a dry, desertic area. After all, that’s where you usually find them. However, a recent discovery, showed that camels originally come from the arctic circle. A giant camel ancestor lived on Ellesmere Island about 3.5 million years ago, and the camels living today are its direct ancestors. The bones they found were about 30% larger than modern camels.
Features that allow the camel to survive in its current habitat, such as the hump (used as fat storage) and their flat wide feet, are just as useful in surviving the harsh climate of the polar region.
Kangaroos, and the rest of the marsupials (koalas, possums, tasmanian devils), have quite a unique reproductive system. They have two lateral vaginas, which lead to two separate uteri. A third canal in the middle (called the median vagina) is used for birth.
The pregnancy stage is very short compared to other mammals, as the barely developed offspring is birthed directly into their characteristic pouch. For example, a red kangaroo’s pregnancy lasts just 33 days, but its offspring (called a joey) stays in the pouch, feeding and growing, for over 190 days, after which it feels confident enough to stick its head out of the pouch. After some time spent inside the pouch and outside it, it leaves the pouch for good after 235 days.
In theory, a mother kangaroo can nurture three young at a time: one developed joey already outside the pouch, one joey inside the pouch and an undeveloped embryo in one of its uteri.
Spiders, ants and other things I don’t like
Australia is well known for harbouring quite the variety of scary critters, and its spiders are no exception. The redback spider is the most poisonous, its venom can be lethal and it causes extreme pain for at least 24 hours. However, since the introduction of an anti-venom in the 1950s, there have been no recorded human deaths.
The Sydney funnel-web spider also has a potentially deadly bite. Thankfully, since an anti-venom was developed in 1981 there have been no recorded deaths. However, in 2012 stocks of the anti-venom were running low, so people were asked to catch them so that they could be milked. It takes about 70 milkings of a spider to produce one dose. You are braver than I am, Australians.
Bulldogs ants (genus Myrmecia) are almost all endemic to Australia. They can grow up to 4 cm in length and are also known for their very aggressive behaviour and their very painful, venomous stings. People who are allergic to the venom can go into anaphylactic shock, which can lead to death. Oh, and did I mention that some of them can fly?
One species of bull ant, the jack-jumper ant, contains all of its genome in 2 chromosomes (males only have one), the lowest number possible for an animal.
There are many more deadly and scary animals living down under, but I will just mention one more, the box jellyfish. The venom of one of its largest species, the Chironex fleckeri, causes cell walls to become very porous, allowing the leak of potassium. The extra potassium in the bloodstream causes hyperkalemia, leading to death in 2 to 5 minutes. Yikes!
Box jelly venom under the microscope – By Anna Salleh – Australian Broadcasting Corporation