If you ever feel a bit out of place, spare a thought for the poor echidna. It's a mammal with spikes, no jaw, and it lays eggs. Echidnas are weird but wonderful.

Anywhere in Australia or Papua New Guinea, if you find yourself outside the city there’s a good chance that an echidna is nearby. Echidnas are small (about 30-45cm from snout to bottom) and quietly waddle around in open forests, scrublands and rocky areas. Their faces may look weird because of their tiny eyes and their long, hard noses that double as mouths; the short, sharp spines that cover the whole upper side of their bodies may make them look dangerous. But echidnas are peaceful creatures that you’ll never need to run away from (unless you’re an ant or a termite, in which case you’re out of luck). Although you should never try to pet one!

Short-beaked echidnas were originally known to British settlers as spiny anteaters. When scientists tried to give it a scientific name, they chose Echidna (Latin for ‘spiny one’). They soon realised, however, that this name had already been given to a spiny type of fish, so a new classification was needed to avoid confusion – they decided on Tachyglossus (‘swift-tongued’). Not surprisingly, the first name had already caught on. So today, even though spiny anteaters are still officially labelled Tachyglossus, the original scientific name Echidna has become the common name.

When first discovered by British settlers, echidnas would not have seemed that weird – they would have reminded them of hedgehogs or porcupines – compared to other Australian animals, which would have seemed very unfamiliar indeed. Scientists in London were so shocked when they first saw a platypus – after all, it looks like a duck crossed with an otter – that they though it must be a fake. But what most disturbed them were the claims from Australians that platypuses and echidnas laid eggs rather than giving birth to live babies like all other known mammals. As far as they knew, birds, reptiles, amphibians, fish and insects laid eggs, but mammals were special because they didn’t.

Above: the skull of a Long-beaked Echidna (left) compared to a hedgehog's skull (right). Both animals have evolved sharp spines, but their skulls show that they aren't closely related.

It took almost a century for the fact that monotreme lay eggs to be proven beyond doubt by the discovery of a pregnant platypus. There are only two families of monotremes: the platypuses and the echidnas. Technically, there are four different species of echidna. There is the familiar, Short-beaked Echidna found throughout Australia, but there also three species of larger, Long-beaked Echidnas found on the island of New Guinea.

BABY ECHIDNAS

Echidnas are not aggressive towards each other or even particularly shy, but they live solitary lives and only associate with other echidnas for breeding. Mother echidnas have only one baby at a time. Unlike a platypus she will not build a nest but instead keep the small, leathery-shelled egg on her at all times in a temporary pouch in her belly. It is believed an echidna can curl into a ball and lay her egg directly into her pouch. After seven to ten days the egg will hatch and a tiny, naked baby echidna will emerge. Looking like a squishy pink jelly-bean, the baby, known as a ‘puggle,’ will remain in its mother’s pouch for about seven weeks. By this time it will have grown to 10cm in length and will have started growing its spines. As you can imagine, this becomes a little uncomfortable for the mother, who will find a hiding place (such as a hollow log or an unused burrow) where the puggle can leave the pouch and continue to grow in safety.

Before and after leaving the pouch, a mother echidna feeds her puggle with her own milk, like all mammals. Unlike other mammals, however, monotremes do not have teats for their babies to suck on. They instead have enlarged pores on their skin, like sweat glands, from which thick, yellow milk oozes. Once a puggle has left the pouch, its mother visits it and continues feeding it milk. The echidna lifts her belly off the ground and uses her snout to push the puggle underneath, where the puggle clamps onto and sucks a milk-filled tuft of hair.

DAILY LIFE OF AN ECHIDNA

When older than six months the puggle will leave its hiding place and start searching for echidna food. Echidnas’ snouts are long tubes containing an even longer, sticky tongue. They rely on smell to find food, and may even be able to detect the tiny electric signals created by other animals. When an echidna finds a nest of ants or termites it uses its sharp front claws to tear it open. With a quick flicking of its tongue, it grabs lots of insects and licks them up its snout. Like platypuses, echidnas do not have teeth, so they crush their food between their tongue and the roof of their mouth before swallowing.

Echidnas are covered in dark, bristly hairs (like most mammals), some of which have evolved into short, sharp spines made from a material similar to human nails. These are an essential defence for a small, slow-moving animal that would be unable to fight predators, such as dingoes. Echidnas have short legs with long claws for digging. One claw on each of its rear paws is extra-long, allowing the echidna to scratch between its spines. When threatened, an echidna digs straight down into the ground, like a ship sinking into water, leaving only its spiky back showing. If the ground is too hard to dig into (and it has to be very hard to stop an echidna’s shovel-like claws), the echidna curls into a ball to protect its soft face and belly. Echidnas do not borrow at any other time; they prefer to rest or hide in pre-made shelters they find while searching for food between naps. During winter their body temperature can drop from an average of about 32°C (most mammals are about 36-39°C) down to 5°C while they hibernate (sleep deeply) for up to 10 days at a time.

NEW GUINEAN COUSINS

The three species of long-beaked echidnas living in New Guinea are all considered endangered. They are much larger than their Australian cousins and can grow to be up to 1m long. Their snout alone may measure 20cm, which they use to earthworms. Their long black fur partially covers up their white spines, but you can be sure that they are still very spiky!

The rarest of the long-noses is called Sir David’s Long-beaked Echidna, named by Australian naturalist Tim Flannery after the famous maker of wildlife documentaries, Sir David Attenborough. It is so rare that it is known from only a single old specimen, and has not been properly recorded since. The destruction of rainforest throughout Southeast Asia leaves less and less room for animals like the Long-beaked Echidna to live in.