Echidnas: Tachyglossidae

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ECHIDNAS: Tachyglossidae

SHORT-BEAKED ECHIDNA (Tachyglossus aculeatus): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

Echidnas (ih-KID-nahz), also called spiny anteaters, are solidly built, short-legged, shuffling mammals that can grow fairly large, up to 14 pounds (6.5 kilograms) for the short-beaked (or short-nosed) echidna and up to 20 pounds (9 kilograms) for the long-beaked (or long-nosed). Head and body length in an adult short-beaked echidna can reach 21 inches (53 centimeters), the stubby tail adding another 3.5 inches (9 centimeters). Head and body length in adult long-beaked echidnas gets as long as 30.5 inches (77.5 centimeters), and the tail, like that of the short-beaked echidna, is a mere stubby shoot. Male echidnas are larger than females. Although echidnas may look overweight, most of the soft tissue mass that might be mistaken for blubber is muscle, lots of it.

The two species look similar but some differences are obvious, especially the snout, which is made of bone, cartilage, and keratin (what claws and fingernails are made of). The snout is shorter and straight or slightly upturned in the short-beaked echidna, but longer, thinner, and downcurving, like the bill of a nectar-sipping bird, in the long-beaked echidna. An echidna's head is small and the neck is not obvious, so that the head seems to flow directly into the body.

Echidnas have full coats of brown or black hair, with scattered, hollow spines, which are really modified hairs, studding the body on the back and sides. The spines are yellow with black tips in some animals, and up to 2.4 inches (6 centimeters) long. In short-beaked echidnas, the spines are longer than the fur, so that the spines are noticeable, but the coat of the long-beaked echidna is just the opposite: the fur is long enough to cover most of the spines.

The four legs are short, with powerful muscles and claws, proper for an animal that frequently digs in the soil and tears open logs and termite mounds. The hind feet point backwards, and are used to push soil away and out when the animal is burrowing.

GEOGRAPHIC RANGE

The short-beaked echidna lives throughout Australia, Tasmania, and the lowlands of New Guinea. The long-beaked echidna lives only in the New Guinea highlands.

HABITAT

The short-beaked echidna lives wherever its main food sources, ants and termites, are abundant enough to keep it fed, allowing the species to occupy nearly all habitat types in Australia and New Guinea, from tropical rainforest and grassland to desert. The long-beaked echidna is confined to alpine meadows up to 12,000 feet (3,660 meters) above sea level, and to humid mountain forests in the New Guinea highlands.

DIET

The short-beaked echidna feeds mainly on ants and termites, but varies its menu with beetles, and grubs, and the like. The animal forages (searches for food) usually by day, or in early morning and evening during very hot weather. It digs up soil, and tears open rotten logs and termite mounds to get at its food. The diet of a long-beaked echidna is almost entirely earthworms, but it varies its diet with insects. The long-beaked echidna feeds at night, poking around in the soil and the blanket of fallen leaves and other litter on the forest floor, sniffing for worms and insects.

BEHAVIOR AND REPRODUCTION

Echidnas are monotremes, their only living relative being the platypus, and the three species together are the only living, egg-laying mammals. The mother echidna bears a single, small egg with a leathery shell that she tucks into a temporary pouch, where the offspring will hatch and nurse itself on milk excreted through pores (but no nipples) in the mother's skin within the pouch.

If threatened, an echidna has several options for defense. It can run, climb a tree, or swim. Echidnas do these things quite well. It can wedge itself into a small cranny between rocks, anchoring itself with its paws and spines. If in the open, the echidna can dig itself a hole well within a minute, burying itself, leaving some of the spines on its back poking above the soil as a final barrier.

ECHIDNAS AND PEOPLE

Echidnas are not as well known as the platypus, but they fascinate naturalists and zoologists for the same reasons: they lay eggs, have a combination of reptilian and mammalian characteristics, and remind us of a time when reptiles were evolving into mammals.

THE ANTEATER SYNDROME

Besides echidnas, several kinds of unrelated mammals that eat mostly ants and termites have evolved in several parts of the world. The others are the anteaters of Central and South America, the aardvark of Africa, the pangolins of Africa and Asia, and the numbat of Australia. Mammals that feast mainly on ants and termites need to be born with certain natural, built-in tools for the job, and all these creatures have them: long, sticky, whiplike tongues that can shoot out of narrow, elongated, tube-shaped snouts; powerful, curved, hooklike claws and heavily muscled limbs for tearing apart termite castles or digging up ant colonies; and powerfully muscled bodies. These animals either have no teeth at all or lose them before they mature (echidnas, New World anteaters, pangolins), lose most of their teeth but keep a few (aardvarks), or seem to be slowly losing their teeth over evolutionary time (numbats).

These ant-eating animals have keen senses of scent and hearing, poor eyesight, and walk clumsily because their long, curved claws slow their gait. They are not diverse. There is only one species of numbat and one of aardvark, two of echidnas, four of New World anteaters, and seven of pangolins. Individual animals of these species lead solitary lives, socialize only to mate, and females nearly always bear and raise one young at a time.

CONSERVATION STATUS

The short-beaked echidna is still plentiful in Australia, and has no special conservation status listing at present. The long-beaked echidna of New Guinea, on the other hand, is faring poorly. Its forest habitat is being cleared for logging, mining, and agriculture, and people hunt the echidna for food with packs of trained dogs. Because of these threats, the long-beaked echidna is listed as Endangered.

SHORT-BEAKED ECHIDNA (Tachyglossus aculeatus): SPECIES ACCOUNT

Physical characteristics: The short-beaked echidna is a compact, heavily muscled, short-legged creature covered with fur and an array of sharp spines. From a distance, it looks and moves something like a porcupine. Up close, it looks less like a porcupine and more like a waddling shrub of grass-like leaves and sharp thorns with a long, probing twig (the snout) at the forward end.

Adult short-beaked echidnas range in head and body length from 14 to 21 inches (35 to 53 centimeters), the stubby tail adding another 3.5 inches (8.9 centimeters). Males weigh about 14 pounds (6 kilograms), while females weigh about 10 pounds (4.5 kilograms).

The pelt (fur) varies in color and thickness throughout the species' range, being darker and thicker as one moves south. In northern Australia, echidna pelts are light brown, while in Tasmania they are black.

Geographic range: Australia, Tasmania, and the lowlands of New Guinea.

Habitat: The short-beaked echidna can live in nearly any habitat where it can count on a steady food supply of ants and termites. This adaptability has allowed the species to occupy nearly all habitat types in Australia and New Guinea, from tropical rainforest and grassland to desert.

Diet: Short-beaked echidnas are ground foragers that feed by wandering across fields and forest floors, sniffing and lightly poking at the soil with their hard snouts, then gouging out dirt with their powerful legs and claws from an area where the animal has detected ants, termites, worms, or other soil-living creatures. Or, an echidna may tear open a rotten log to get at ants, or a termite mound for termites. Once an echidna has exposed the insects or worms, it shoots out its long, ropy, sticky tongue, laps up the insects, then reels in the tongue, loaded along its length with up to twenty insects at a time.

Behavior and reproduction: Short-beaked echidnas have one annual breeding season, July through August. Courtship behavior in echidnas is a sight not soon forgotten, since several males will follow single file in an "echidna train" behind a female for one to six weeks. Sooner or later, the female halts and the males encircle her continuously, gouging out a circle of dirt around her. The female at last selects one male from the gang and mates with him, after which the two part and go separate ways. Fathers do not help with raising the young.

About twenty-four days after mating, the female lays her egg. When the mother senses that the egg is ready to emerge, she lays on her back and guides it as it slowly rolls down and over her underbelly and into the pouch, which closes to hold and shelter the egg.

A newly hatched echidna is the size of a jellybean. The mother carries the hatchling in her pouch for fifty to fifty-five days. She then removes the youngster and hides it in a burrow or cave, returning every five days to nurse the infant. The youngster is able to move about and forage but continues to nurse until it is six months old, and becomes independent at one year of age.

To protect itself, a short-beaked echidna may wedge itself into small spaces in burrows, rocks, or tree roots, where it can secure itself by using its claws and spines to wedge its body within the space. If caught in the open, the echidna can roll itself into a ball, head and legs tucked underneath and the protective spines pointing outward. It can also burrow and bury itself in the soil within a minute, leaving only its topmost spines visible as a final defense.

Short-beaked echidnas and people: Most people in Australia are either fond of echidnas or indifferent toward them. They are not considered pest animals.

Conservation status: Short-beaked echidnas are protected by law in Australia, and are plentiful there, since they can adapt to a wide range of habitats. Despite their high population, their numbers are declining. Research on short-beaked echidnas is ongoing at Pelican Lagoon Research Center on Kangaroo Island, Australia. ∎

FOR MORE INFORMATION

Books:

Kennedy, Michael, compiler. Australasian Marsupials and Monotremes: An Action Plan for Their Conservation. Gland, Switzerland: IUCN, Species Survival Commission, Australasian Marsupial and Monotreme Specialist Group, 1992.

Rismiller, Peggy. The Echidna: Australia's Enigma. Westport, CT: Hugh Lauter Levin Associates, 1999.

Stodart, Eleanor. The Australian Echidna. Boston: Houghton Mifflin Company, 1991.

Periodicals:

Griffiths, M., B. Green, R. M. C. Leckie, M. Messer, and K.W. Newgrain. "Constituents of Platypus and Echidna Milk." Australian Journal of Biological Science no. 37 (1984): 323–329.

Vergnani, Linda. "On the Trail of Scientific Oddballs. (Peggy Rismiller studies echidnas)." The Chronicle of Higher Education 48, no. 11 (Nov 9, 2001): A72(1).