12 Things You Didn't Know About the Strange and Spiky Echidna

The echidna is often called a spiny anteater for its needle-shaped nose and porcupine-like quills, but it isn't, in fact, an anteater at all. And that's just one of the many ways the unusual creature defies categorization. The last surviving members of the order Monotremata, native to Australia and New Guinea, are enigmatic among mammals, with their peculiar egg-laying and androgynous pouches. Here are a few things you may not know about these anomalous, spike-bearing animals from Down Under.

1. Echidnas Are One of the Only Mammals That Lay Eggs

Other than echidnas, the only mammal that lays eggs is the duck-billed platypus, which happens to be its closest relative. Each year, the female echidna lays a single egg — about the size of a dime — which she rolls into a kangaroo-like pouch that develops just for the occasion. About 10 days later, her young will hatch and remain in the pouch, lapping up milk secreted by its mother, until it's nearly two months old.

2. They're Also One of the Oldest Species on Earth

Echidnas evolved from the monotreme lineage between 20 and 50 million years ago. Although limited fossil records make it impossible to know who its earliest ancestor is, it's thought to have been a terrestrial insectivore similar to the platypus. The once-diverse group from which they both hail has over centuries been reduced to just four echidna species (three long-beaked, one short-beaked) and one platypus species. Unlike their aquatic relatives, echidnas have adapted to life on land.

3. Their 'Beaks' Are Actually Noses

And about those so-called beaks: They're actually just noses. The extended, rubbery snouts — varying from short to long, depending on the species — are strong enough to break open hollow logs and dig for insects underground. An echidna can also use its nose to sense vibrations made by prey. The length allows them to penetrate small spaces in search of ants and termites, their primary food source.

4. They Have No Teeth

To eat those ants, termites, and beetle larvae, the echidna uses only its long and sticky tongue. Like anteaters, they have no teeth, but with hard pads on the base of their slender tongues — which they can extend up to an impressive 6 inches — and on the roof of their mouths, they can grind up their grub into a more manageable paste.

5. Both Sexes Have Pouches

In yet another perplexing deviation from the mammalian norm, both sexes of echidna have pouches on their bellies. In the case of kangaroos, opossums, and koalas, only the females have pouches in which to keep their young. According to the San Diego Zoo, the fact that both males and females have this trait makes it difficult to tell the sexes apart.

6. Their Spines Protect Them From Predators

According to the San Diego Zoo, echidnas deal with predators three ways. They either run on their tiny, stubby legs, curl up into themselves, or — their best defense mechanism — dig holes to hide in. The critters are quick diggers and can seek safety in a shallow hole where only their faces and feet are hidden but their rears are still exposed. Predators (foxes, goannas, Tasmanian devils, etc.) often prove they are not hungry enough to grab at a spiky ball.

7. Each Spine Can Be Moved Independently

Made of keratin and growing to be as long as 2 inches with sharp ends, its barbless quills are actually more like hair than spikes. There are muscles at the base of each spine that allow the echidna to move them independently. This comes in handy for wedging itself tightly into rock crevices for protection, or righting itself if it ever gets rolled onto its back.

8. They Have the Lowest Body Temperature of Any Mammal

The echidna maintains a body temperature of about 89 degrees F (32 degrees C), which is thought to be the lowest body temperature of any mammal on the planet. What's more, their body temperatures can fluctuate drastically — by about 10 to 15 degrees F — throughout the day. A healthy human's body temperature fluctuates only about .9 degrees daily, for comparison.

9. Baby Echidnas Are Called Puggles

Baby echidnas are called puggles, a name they share with a common mixed breed of dog. They hatch from their eggs after 10 days of gestation, then move out of their mothers' pouches after about two months, just when they begin developing their signature spines. The puggles will then stay in burrows, being fed by their mothers every five to seven days, until they're about 7 months old, when they go off to live on their own.

10. Males and Females Have Foot Spurs for Different Reasons

A 2013 study published in PLOS ONE found that although both males and females have spurs on their hind legs, those spurs serve very different purposes. Males use their spurs to release venom, directed at other males during the breeding season. Females, on the other hand, are thought to release a milky substance from their spurs that attract mates. The latter loses theirs before maturity.

11. They Have Surprisingly Long Life Spans

Their consistently low body temperatures and slow metabolism are likely to play a major role in echidnas' strikingly long life spans. These animals can live between 30 and 50 years both in the wild and in captivity, but research shows they tend to live longer in captivity. That's more than twice as long as its closest relative, the platypus, lives — which is about 17 years, on average.

12. Most Echidna Species Are Critically Endangered  

Due to habitat destruction and hunting, the eastern long-beaked echidna, western long-beaked echidna, and Sir David’s long-beaked echidna — named after Sir David Attenborough — are critically endangered. According to the International Union for Conservation of Nature (IUCN), the entire long-beaked variety has declined 80% in population over the past 50 years. In Australia, many are hit by cars. The more populous fourth species, the short-beaked echidna, is labeled Least Concern and is protected by Australian law.