Forget the Platypus. The Echidna Is the True Champ of Weird

This long-beaked echidna just can't even. Can't. Even.

Knuckles from the Sonic the Hedgehog games is supposed to be an echidna, one that flies around like Superman and runs so fast its legs become blurs. “Knuckles is a cool guy with a bad attitude,” claims Urban Dictionary in increasingly stilted English. “He does’nt [sic] like to be pushed around. Him and Sonic fight a lot, but I think their [sic] good buddies.”

Other than the being friends with hedgehogs bit, it’s not an inaccurate description of actual echidnas, the great misfits of the mammal family. There’s four species, including one in Australia called the short-beaked echidna. But it’s New Guinea’s three species of the little-studied long-beaked variety, which I’ll be focusing on here, that really amp up the weirdness—as you might have noticed from the photo above.

These nocturnal creatures lay eggs like reptiles and detect electrical fields like sharks. They’ve got the mug of an anteater and the spines of a porcupine. And of course the males have four-headed penises like … well, maybe something out of hentai?

Bowed Legs and Laid Eggs

It’s a good idea to start here by talking about mammals’ ancient ancestors the synapsids for a hot second. They superficially resembled modern reptiles (though reptiles are a distinct lineage), yet had many mammalian characteristics as well. Synapsids eventually gave rise to the three groups of mammals: monotremes, which include only the platypus and echidnas; placental mammals like humans; and marsupials. The monotremes split off from the mammalian lineage first, and did so very, very early on, some 200 million years ago, and today retain many “reptilian” features of their ancestors.

Perhaps the most conspicuous reptilian quality is the long-beaked echidna’s odd posture, which makes it look like a meathead that just got his pump on. “The legs are kind of splayed out to the side somewhat, like you might imagine a lizard whose legs kind of shoot out and then go down,” says Kristofer Helgen, a zoologist at the Smithsonian. “Whereas most of the mammals we’re familiar with, whether it’s us or a dog or a horse or a kangaroo, the legs go straight down under the body and support it. And so these things have more of a splayed reptilian posture.”

But where the echidna one-ups the reptiles is with its penis. Let me rephrase that. The echidna’s penis is far more fascinating than a reptile’s, specifically the fact that it has four heads, whereas reptiles have dual penises called hemipenes. However, the female echidna has only a paired vagina, so why the mismatch? Well, it seems the male will alternate, using two heads to inseminate the female before switching to the other two heads and inseminating again.

This is what the long-beaked echidna version of that beach scene from the movie 10 looks like.

Another reptilian characteristic is of course the fact the long-beaked echidna lays eggs. And while the female has a pouch like a marsupial, there’s one significant difference: this pouch isn’t permanent. “So what’s crazy about it is basically the muscles in the skin of the belly of the echidna temporarily form into a pouch that can house the baby or babies when they’re hatched out of the egg,” Helgen says. Here the young don’t suckle nipples, but instead lap up milk from glands that leak the stuff directly onto the mother’s fur.

But why would the platypus and echidna go the egg-laying route when every other mammal gives birth to live young? Well, the beauty of evolution is that different strategies suit different organisms perfectly fine, however ridiculous they may seem. Placental and marsupial mammals evolved to give birth to live young, while the monotremes held onto the egg-laying ways of their ancestors. Keep in mind that creatures are on Earth for one purpose only: to reproduce (the meaning of life is therefore nothing like what Monty Python says). If something is at all inefficient in that regard, that’s it for the species. Yet here, after hundreds of millions of years of evolution, is the echidna. It’s got a weird sex life, sure, but it works.

The Hunter and the Hunted

When the little long-beaked echidna eventually sets out on its own, it’s well-equipped to run down earthworms and millipedes and other invertebrates in the soft soils of New Guinea. Just like the platypus can pick up the electrical signals of its prey in the water using its bill, the long-beaked echidna uses its giant, electricity-detecting snout to probe for food in the darkness (the short-beaked echidna hunts social insects like ants, and therefore has no use for such a long schnoz). Strangely enough, though, the echidna has no teeth. Instead, it uses its tongue, which is studded with lots of tiny, sharp spines, to grind the prey against the roof of its mouth, which also has these spines.

And the echidnas share another extraordinary adaptation with their platypus relatives. “Platypuses are known to be venomous, and they have on their hind foot a spur that’s connected to a venom gland that’s situated just below the knee,” says Helgen. The long-beaked echidna has a similar structure, and “a lot of people have said it’s not poisonous, but studies are ongoing now that suggest that they may also be venomous at certain times of year.”

The less absurd though no less thorny short-beaked echidna crossing “conquer a log” off its bucket list.

As with the platypus, it may be a defensive adaptation, which Helgen experienced firsthand while doing fieldwork in New Guinea, where one long-beaked echidna put up a bit of a fight. “It was trying to dig and escape, but when I did manage to pick it up it was contorting its body. And it seems like it was trying to stick me with that thing.”

Sadly, such weapons—combined with its many spines—can’t protect the long-beaked echidna from humanity at large. Like much of Earth’s endangered wildlife, the three species of long-beaked echidna have the unfortunate distinction of being palatable to humans (luckily, the short-beaked variety in Australia seems to be doing OK). Also like much of Earth’s endangered wildlife, the echidnas find themselves ever more crowded out by human settlements.

That could all spell disaster for the species. “You can talk to people in areas where this animal lives,” says Helgen, “and even though older men—maybe they’re in their 50s, 60s, and 70s—they can usually count on two hands how many times they’ve hunted and killed these animals.” Part of the problem has been dogs. While a hunter will have a hard time tracking the nocturnal creatures, canines certainly won’t. By hunting with dogs, a party can rapidly clear entire areas of any long-beaked echidnas.

Read more at Wired Science