Tuesday, October 11, 2022

No Kidding, an Echidna


While I usually cover flora and fauna relevant to the US Northeast and southeastern Canada, every so often, a non-regional subject whispers to me that it’s endlessly captivating and deserves an essay. Eventually I comply to make the whispering stop. Please don’t tell my shrink about this. One time, I was forced to write about platypuses (compelled by platypuses, not editors). These things are proof that animals are not the result of evolution; no, they came from Ikea. Ma Nature went to Ikea for her animals, and after assembling them, a little pile of fasteners and animal parts were left on the workbench.

With imagination, and possibly a stapler, she made an adorable muskrat-duck combo. But while female platypuses have two ovaries, only the left one works. The left-ovary thing makes sense, given that platypuses were likely made from leftovers. Recently I stumbled (not literally) upon an animal which, though related to platypuses, outshines them by far in their weird combination of traits. Found throughout Australia and parts of New Guinea, the short-beaked echidna (Tachyglossus aculeatus) is half porcupine and half anteater, roughly.


It may not sound like it, but these guys are cute as hell. Echidnas are pointy-snouted mammals that lay eggs and have a marsupial-like pouch, except it only appears when they need a pocket for babies. Speaking of babies, female echidnas have two vaginas. The males, typically competitive I suppose, not only evolved to be 25% larger than females, they have four penises (it seems they employ their members alternately). Copulation must be a challenge, what with sharp spikes all over and mismatched multi-genitalia, but evidence suggests they get the job done: echidnas have been around for 48 million years, give or take.


Bizarre sex is nothing compared to what comes out of an echidna egg. Females lay one soft-shell egg per “litter” directly into her pouch, which magically forms as a fertilized egg begins to develop inside her. When the wee critter breaks through the eggshell with its bird-like egg-tooth, a baby echidna does not step out. Instead, an amorphous, spineless, gummy-bear-thing known as a puggle emerges in Mommy’s baby-pocket. Supposedly, these translucent larva-esque pink puggles will turn into echidnas after about fifty days, but I can’t imagine that’s true. Until someone puts a baby-cam inside the pouch, I think some kind of conspiracy may be afoot.

Echidna. Wikimedia Commons photo.

Speaking of foot, echidnas use their feet differently than other animals do. First, the hind feet point backward. Offhand, I’d call this a serious design flaw, like platypuses left-ovary production error. Here’s a great description of how rear-pointing feet affect echidnas’ movement. Writing for Atlas Obscura on August 4, 2022, Jack Ashby says echidnas walk “…as if at the behest of someone who is learning how to operate a remote-controlled robot, stopping and starting and changing direction every couple of steps. The way their limbs move, held at 90 degrees from the body, is unique.”


However, this odd feature helps protect them. You’d think curling into a ball of spines would be enough to deter carnivore species from eating them, but echidna undercarriages lack quills. If a predator were to flip one over, the odds would not be ever in its favour. The echidna’s fix is to shimmy their stout paws vigorously back and forth, which lets them sink up to their bellies into the ground. With two feet forward and two aimed backward, echidnas are locked-down almost as well as one of those screw-in earth anchors that folks use for securing large tents.


When they’re not hiding from domestic dogs and red foxes (an invasive species in Australia), echidnas mainly amble around and forage. Their diet consists almost entirely of ants, termites, and dirt. The latter may be incidental, as their long, sticky, Jar-Jar Binks sort of tongues, perfect for persuading ants to leave home, also bring in stray sand particles. Glue-covered tongues are just one strategy to get ants. Three related species of long-nose echidnas, critically endangered and exclusive to New Guinea, have spines on their tongues to snag termites and ants. Adhesive or spiky tongues might explain why echidnas do not kiss during courtship.


Among the echidna’s cool features is the ability to sense minute electrical fields with their snouts. It likely aids them in detecting nearby hidden termites, and is only good within a short radius around their snoots. Just about all aquatic organisms have electroreceptors, but echidnas and platypuses are the only land mammals that come standard with this option. It’s thought that echidnas once spent much of their lives in the water, where electric fields can be detected kilometres away. They can swim, but they live and feed exclusively on dry land.


A somewhat more obscure point is that male echidnas have “venomous” leg-spurs that lack venom. Platypus males have similar, though fully-loaded, spurs which pack a wallop, reportedly enough to kill a dog. For guy-echidnas, having leg spurs is the equivalent of a replica gun visible in your waistband. Maybe it’ll make a predator think twice, and maybe it won’t. The short-beaked echidna does not tolerate extreme temperatures, which makes you wonder why they’re doing so well in Australia. The answer is that during periods of intense heat, they find shelter in rock crevices, under forest debris, or even in vacant dens of other animals such as the wombat.


As with so many other species, it remains to be seen how our ever-warming climate will affect them in the future. Who knows; maybe they’ll become established here one day.


Paul Hetzler is a former Cornell Extension educator. He likes the word “wombat.”


Photo at top: Echidna. Wikimedia Commons photo.

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Paul Hetzler has been an ISA Certified Arborist since 1996. His work has appeared in the medical journal The Lancet, as well as Highlights for Children Magazine.You can read more of his work at PaulHetzlerNature.org or by picking up a copy of his book Shady Characters: Plant Vampires, Caterpillar Soup, Leprechaun Trees and Other Hilarities of the Natural World


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