Belonging to the scientific family Tachyglossidae, these spiny anteaters got their name from a creature described in Greek mythology, who was half-woman and half-snake, since the animal appeared to have qualities of both mammals and reptiles. Though a mammal, these creatures lay eggs, making them a member of the scientific order Monotremata; besides echidnas, the platypus is the only other member of this order. There are three known genus of echidnas, but only four currently existing species; there are four other extinct species known only by fossil records.
Like the platypus, echidnas evolved from an aquatic ancestor, but over time adapted to life on land. These animals are found in Australia and New Guinea, making homes in forests and woodlands. They do not tolerate extreme temperatures and use caves, rock crevasses, and the burrows of other animals as shelter. Being capable swimmers, they venture into water in order to bathe and groom themselves.
Though the diet of an echidna consists of ants, termites, worms, and insect larvae, they are not closely related to the anteaters of the Americas. They have course hair and spines, much like a hedgehog or porcupine, and are usually black or brown in colour, though albinos have been reported. The elongated, slender snout functions as both a nose and mouth and long-billed species can have as many as 2,000 electroreceptors; short-billed species can have as few as 400 electroreceptors. Their ears, which are typically unseen due to the hair and spines, are simply slits on the side of their heads.
Short, strong limbs with large claws make these animals powerful diggers. They tear open logs and anthills, and use their long, sticky tongues with tiny sharp spikes to collect prey. Their mouths are tiny and their jaws are toothless, so they break down their food by grinding it between the bottom of their mouth and their tongue.
Being solitary creatures, they have large mutually overlapping territories. With a low metabolism and stress resistance, their lifespan in the wild is typically around 16 years, however accounts of individuals reaching 45 years have been recorded. In captivity, the lifespan can reach 50 years.
The part of the cerebral cortex concerned with sight and hearing in mammals, known as the neocortex, makes up half of the echidna brain, whereas in humans it only makes up about 80 percent. Temperatures must also be around 25 °C (77 °F) order for echidnas to reach REM sleep.
Females weigh around 4.5 kg (9.9 lbs) and the males around 6 kg (13.2 lbs). On average the males are 25 percent larger in size, and have non-venomous spurs on their hind feet. Though the reproductive organs differ in each sex, both have a single opening, called a cloaca, which is used to urinate, release faeces, and mate.
Breeding season begins in June and extends into September, and the mating ritual is fairly odd. Know as the ‘train’ system, males will form lines up to ten individuals long and follow a female, each attempting to mate. Males may switch to different lines if they are unsuccessful. In the wild, it is challenging to observe them; in captivity they show no interest in mating, so no one has apparently ever seen an echidna actually ejaculate. Attempts at electrically stimulated ejaculation in order to collect semen samples have only resulted in penis swelling.
Amazingly, the male echidna has a four-headed penis, which is covered in penile spines to induce female ovulation. During mating, two of the head shut down and do not grow in size; the other two are used to release the semen into the female’s two-branched reproductive tract. Each time the male copulates it alternates the heads in sets of two.
Twenty-two days after mating, the female will deposit a single, soft-shelled, leathery egg, weighing about 380 mg (.38 g) into her pouch, which hatches after about ten days. The young echidna, which is called a puggle, remains in the pouch for up to 55 days while it develops spines and sucks on milk patch pores (monotremes do not have nipples!), after which the mother digs a burrow for the young. The mother returns to the puggle every five days to suckle until it is weened at about seven months.
Predators to these animals include foxes, domestic dogs, wild cats, and goannas. Snakes can also slither in to burrow and prey on the defenseless young puggle. When an echidna feels threatened, it will use it’s spines as a sheild and curl itself into a ball or attempt to bury itself. Keeping the environment clean of litter, planting vegetation for echidnas to useas shelter and supervising pets are all ways of helping to protect these special little creatures. Report hurt echidnas and/or leave them undisturbed, grabbing them may cause stress and could result in injury.
Here’s a fun and informative video with the reincarnation of Steve Irwin, Andrew Ucles, as he finds a echidna in the wild! (Warning: he’s very attractive):