Short-Beaked Echidna: Facts About the Spiny Anteater

What is an echidna?

Echidnas belong to the monotremes, an ancient group of mammals that lay eggs instead of giving birth to live young. There are only five living monotremes: the platypus and four echidnas. The short-beaked echidna is the smallest and by far the most widespread; the other three, the long-beaked echidnas of the genus Zaglossus, live only in New Guinea and are much larger and critically endangered.

Monotremes are still true mammals. They have fur, are warm-blooded and feed their young on milk, as explained in is a platypus a mammal? Like birds and reptiles, though, they have a single opening, the cloaca, for waste and reproduction.

The echidna was once commonly called the spiny anteater, but it is not closely related to the true anteaters of the Americas. The similarities, such as a long snout, a sticky tongue and no teeth, evolved independently because both eat ants and termites.

Appearance

The short-beaked echidna has a rounded, dome-shaped body covered with cream-colored spines tipped in black or brown. The spines are modified hairs made of keratin and can be up to 5 cm (2 in) long. Between them grows a layer of fur that ranges from honey-colored to dark brown or black. Tasmanian echidnas have much thicker, longer fur that can almost hide the spines.

The head merges into the body without a visible neck. The snout, or beak, is a tube about 7.5 cm (3 in) long with the nostrils and a tiny mouth at the tip; the mouth opens no wider than about 5 mm (0.2 in). The eyes are small, and the ear openings are hidden in fur.

The short legs are extremely powerful. The front feet have broad, flattened claws for digging, and the hind feet point backward, with a long, curved grooming claw used to clean between the spines. Males have a small spur on each hind ankle, but unlike the platypus spur it is not connected to a working venom gland.

Size

Size varies across the range, and the Tasmanian subspecies is generally smaller than mainland echidnas. Males are usually somewhat larger than females.

Scientists usually recognize five subspecies, which differ mainly in fur thickness, spine length and size: one each in Tasmania, Kangaroo Island, southwestern Australia, the rest of mainland Australia and New Guinea. Despite these regional differences, all short-beaked echidnas share the same basic body plan, a design that has changed little over millions of years.

Habitat and range

The short-beaked echidna is the most widespread native mammal in Australia. It lives in every state and territory, from tropical forests in the north to the snowy Australian Alps, the deserts of the interior and the cool forests of Tasmania. It is also common on Kangaroo Island and some Bass Strait islands. Outside Australia, it lives in lowland areas of southern and eastern New Guinea.

Echidnas need little more than a good supply of ants or termites and somewhere to shelter. They rest in hollow logs, under thick bushes, among rocks, in burrows dug by other animals or in shallow digs of their own. They often turn up on farmland with fallen timber and even in suburban gardens on the edges of cities.

By digging for food, echidnas turn over large amounts of soil every year. This helps water and leaf litter soak into the ground and creates small pits where seeds can settle, so ecologists regard echidnas as important “ecosystem engineers,” especially in places where other native digging mammals, such as bilbies and bettongs, have disappeared.

What do short-beaked echidnas eat?

Short-beaked echidnas are insectivores that eat mainly ants and termites, plus beetle larvae, earthworms, moth larvae and other soil invertebrates. They break into nests, rotting logs and soil with their strong claws, then use their long, sticky tongue to collect the insects. The tongue can flick in and out about 100 times a minute.

Echidnas have no teeth. Instead, horny pads on the back of the tongue and the roof of the mouth grind food into a paste. Their diet changes with the region and season: termites dominate in dry areas, while ants and scarab beetle larvae are more important in wetter places. The full story is in what echidnas eat.

Senses and special abilities

The echidna’s snout is packed with sensory equipment. Touch receptors pick up tiny vibrations, and electroreceptors at the tip can detect the weak electrical fields produced by the muscles of prey. The echidna has far fewer electroreceptors than the platypus, probably only a few hundred compared with tens of thousands, and smell is probably its most important sense when foraging.

Echidnas are also remarkable diggers and survivors. They can tolerate high levels of carbon dioxide in burrows, swim using the snout as a snorkel, and lower their metabolism to save energy after bushfires, when food is scarce.

Behavior and hibernation

Echidnas live alone and do not defend territories. Each animal wanders over a home range that typically covers around 40–60 hectares (100–150 acres), overlapping freely with the ranges of other echidnas.

They are active by day in mild weather but switch to dawn, dusk and night activity in hot weather, because they cannot sweat or pant and overheat easily. They have a low body temperature for a mammal, about 30–32 °C (86–90 °F), and a body temperature much above 34 °C (93 °F) is thought to be dangerous for them. In hot weather they shelter in burrows, logs or deep leaf litter during the day.

In winter, many echidnas enter long periods of torpor or true hibernation, especially in cooler regions. Their body temperature can drop to around 4–5 °C (39–41 °F), and their heart rate falls to just a few beats per minute. For other mammals that sleep through the cold months, see animals that hibernate.

When threatened, an echidna either curls into a tight, spiky ball or digs rapidly straight down, wedging itself into the soil so that only its spines are exposed.

Reproduction: eggs and puggles

The breeding season runs roughly from June to September, during the Australian winter and early spring. Several males may follow a single female nose-to-tail for days or even weeks in a so-called “echidna train,” with up to about ten males in a line.

About three weeks after mating, the female lays a single soft, leathery egg, about the size of a grape, directly into a temporary pouch on her belly. It hatches after about ten days. The tiny young, called a puggle, is about 1.5 cm (0.6 in) long and drinks milk that oozes from milk patches inside the pouch, since monotremes have no nipples.

When the puggle’s spines begin to grow, at around two months, the mother leaves it in a nursery burrow and returns every few days to feed it. It is weaned and leaves the burrow at about six to seven months old. Read more in what a baby echidna is called.

Lifespan

Short-beaked echidnas are unusually long-lived for a mammal of their size, probably because of their low body temperature and slow metabolism. In the wild, many live 10–15 years or more, and some individuals in long-term studies have been estimated at more than 40 years old. The longest-lived known echidna reached 49 years at Philadelphia Zoo in the United States, an extraordinary age for a mammal weighing only a few kilograms.

Predators, threats and conservation status

Adult echidnas have few natural enemies, but young echidnas are vulnerable. Predators include dingoes, red foxes, feral cats, goannas (large monitor lizards), Tasmanian devils, snakes and birds of prey. Dingoes are known to roll echidnas over to attack the soft belly.

The main human-related threats are road traffic, habitat clearing for intensive agriculture, introduced predators and an introduced tapeworm that can be fatal to echidnas. In New Guinea, hunting with dogs has reduced numbers in some areas.

The short-beaked echidna is listed as Least Concern on the IUCN Red List. It is widespread and common in much of Australia and can survive in farmland and on the edges of towns, as long as fallen logs and ant and termite nests remain.

Echidnas and people

The echidna features in the stories and art of many Aboriginal Australian peoples, and it was a totem for some groups, such as the Noongar of southwestern Australia. Today it appears on the Australian five-cent coin, and an echidna named Millie was one of the mascots of the 2000 Sydney Olympics.

If you meet an echidna in the wild or on a road, the best thing to do is watch quietly and let it go on its way. Picking one up stresses the animal and risks injury from the spines.