Nature Feature - Echidna

Also known as the Spiny Anteater or Porcupine, the echidna belongs to the scientific family 'Tachyglossidae'. There are only two living genera in this family, each represented by a single species. The short-beaked Echidna is a variable species occurring in aImost all Australian habitats and in the lowlands of New Guinea. Several genera of much larger long-beaked echidnas were widespread over Australia and New Guinea until the late Pleistocene era. Now, however, there remains only one, restricted to the highlands of New Guinea. Both forms feed by means of a long, sticky tongue but, while the short-beaked Echidna eats ants and other colonial insects, the Long-beaked Echidna forages in forest litter, eating earthworms and larger solitary insects.

Short-beaked Echidnas attain a length of 30 to 45 centimeters and a weight of between 2 and 7 kilograms. They can be easily identified by the spines which cover the dorsal surface of the body and the rudimentary tail. Fur is usually present between the spines and in the Tasmanian form, often obscures the spines. The animal has a long tubular snout.

The Echidna is a solitary animal, occupying overlapping home ranges which lack fixed nest sites. It usually seeks shelter under thick bushes, in hollow logs, under piles of debris or occasionally in a burrow.

A female with suckling young spends most of the period of lactation in a burrow. In arid regions, Echidnas avoid temperature extremes by sheltering in caves or crevices and restricting activity to the night. In more temperate climates the pattern of activity depends upon the air temperature. They normally forage around dawn and dusk but, in winter, particularly in southern latitudes, may be active in the middle of the day.

The Echidna is common throughout most of Australia from regions of winter snow to the deserts and has no particular habitat requirements other than a supply of the ants and termites on which it feeds. A toothless and highly specialised feeder, it breaches an ant or termite nest with its forepaws or snout and extends its long tongue into the galleries. Insects adhering to the copious sticky saliva with which the tongue is covered are drawn into the mouth and masticated between a horny pad at the back of the tongue and a similar structure on the palate.

A considerable amount of soil and nest material is ingested and this forms the bulk of the distinctive cylindrical droppings.

The male has a spur on the ankle of its hindleg similar to that of the male Platypus but lacking a functional venom gland. Mating occurs in July and August, during which time a single female has been observed to be followed by as many as six males. About two weeks after copulation, a single soft-shelled egg is laid directly into the pouch on the belly of the female. It hatches after about 10 days and the young remains in the pouch for a further 3 months, suckling on milk exuded from the numerous pores of the paired mammary glands. By the time it leaves the pouch, the juvenile has a covering of short spines. The relationship between it and its mother over the subsequent 7-8 months is unknown but juveniles tend to be first seen from September to November when they are a year old and weigh 1-2 kg.

The spiny coat provides an excellent defence. When suddenly disturbed in the open on hard ground, an Echidna curls into a ball of radiating spines. If on soil, it may dig itself below the surface while remaining horizontal, disappearing like a sinking ship. By extending its spines and limbs, it can wedge itself securely in a rock crevice or hollow log.

There are no significant predators of adult echidna, but dingoes occasionally eat them. Young Echidnas may be eaten by large goannas. Their distribution it sparse, particularly in the arid parts of their range, but the species remains ubiquitous and in no apparent danger.

Sources:
'Complete Book of Australian Mammals' - Australian Museum, 1983.
Australia's Wilderness Heritage - Flora & Fauna, 1988.

(Tachyglossus aculeatus).