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The platypus regularly features on lists of the planet's weirdest mammals. It's not difficult to see why, though perhaps it's more fair to describe this semiaquatic Australian creature as unconventional, rather than weird.
Native to the rivers of eastern Australia, the platypus belongs to a small subset of egg-laying mammals known as monotremes (echidnas, the only other members of this category, are also found Down Under). Like all other mammals, platypus mothers have mammary glands that produce milk to feed their young, yet they don't have teats. Instead, they secrete milk out through ducts in their skin, almost like sweat. Platypus babies (which are sometimes, adorably, called puggles or platypups) lap up the milk that collects in grooves of skin or suck it from their mother's fur. This isn't particularly hygienic, as the milk comes into contact with whatever is on the mother's skin. Yet nature has an answer for that – the milk is full of antibacterial proteins that help prevent the babies from getting sick.
There are plenty of other anatomical oddities about the platypus that have baffled scientists for centuries. Male platypuses have a venomous spur on each of their hind legs. Though not fatal to humans, the venom is powerful enough to cause extreme pain and illness in those unlucky enough to encounter it. Another oddity is that platypuses lose their teeth before reaching adulthood, and instead have two hard grinding plates for mashing their food. And the weirdness doesn't stop there. Platypuses don't have stomachs – their gullets connect directly to their intestines.
The weird and wonderful platypus:
- Platypuses and other monotremes are sometimes described as "ancient" or "primitive." They existed long before other mammals evolved, which is why they retain features more commonly seen in birds, fish, and reptiles, such as laying eggs.
- To help them hatch, platypus babies are born with a sharp "egg tooth" made of keratin that they use to cut through the eggshell. This tooth will eventually fall off.
- Perhaps the most distinctive feature of the platypus is its duck-like bill, which is an extremely useful tool for hunting. When submerged, receptors on its bill detect electrical currents produced by tiny animals like crustaceans, which then become platypus prey.
- The platypus is truly a genetic oddity. A platypus has 10 sex chromosomes, whereas all other mammals have just two.
- Contrary to popular belief, the plural of platypus is not "platypi." The plural form is either "platypuses" or simply "platypus." "Platypi" is an example of psuedo-Latin, which doesn't match the word's Greek origins.