MONOTREMATA; Family TACHYGLOSSIDAE
This family of mammals in the order Monotremata is comprised of two Recent genera, each of which contain a single species. Tachyglossidae, also known as Echidnas or Spiny Anteaters, are found in Australia, Tasmania, and New Guinea.
Echidnas bodies are covered with fur intermixed with dorsal and lateral barbless spines. As a general rule, males tend to be larger in size than females - each sex being muscular, yet limber. Enchidnas feet have between three and five claws, curved for digging, with the second toe on the hind foot extended for scratching and preening. Eyes are smaller than that of their cousins, the Duck-billed Platypus (Ornithorhynchidae). Their auricles (pinna of the external ear) are well developed, but is partially concealed in the pelage (coat, or fur). Olfactory senses are extremely sharp and perceptive. As with humans, Echidnas have vestigial tails.
The brain is relatively large, encased in a large, rounded skull, with intricate and complicated cerebral hemispheres. The snout (rostrum) is long, tapered and tubular, supported by a lower jaw made up of two slender bones housing a small toothless mouth. Tongues are equipped with long, sticky posterior serrations which are horned for grinding food against hard palate ridges. Their tongues also have enlarged salivary glands which produce a sticky mucus for eating.
As stated above, Echidnas are remarkable diggers, being able to burrow at extraordinary rates. They live in burrows and cavities under roots or rocks, and inside logs. Using their powerful feet and spines, Echidnas can wedge themselves in their burrows, or other small cracks and fissures, in such a way as to make it impossible to dislodge them. In this respect, they behave much like the hedgehog (Erinaceus). Enchidas have been known to survive for as long as a month without any form of nourishment. While malnutrition makes them lethargic, they do not hibernate (Tachyglossus at least) in response to cold. Their main diet is comprised of worms, ants, termites, and other insects.
Unlike other mammals, or even lizards, Echidnas do not have complex behavioral postures for aggression, courtship, or grooming. They are quite simple animals, and generally live solitary lives. During the breeding season females develop ad interim abdomen pouches, where eggs (seldom more than one - rarely two or three) are transferred directly from the cloaca. These pouches have mammary glands which produce thick, yellowish milk. Hatchlings are naked and measure about 12 mm in length, remaining in the pouch for up to eight weeks, by which time their spines have begun to develop. By this point, the young measure 90-100 mm in length. Mothers periodically nurse young after they leave the pouch, depositing them in sheltered locations so that they can continue to develop in relative safety. By the end of their first year of life, Echidnas have reached sexual maturity.
Tachyglossidae are known to have existed as far back as the Pliocene in Australia and the Pleistocene in New Guinea and Tasmania.
Short-nosed Echidna MONOTREMATA; TACHYGLOSSIDAE; TACHYGLOSSUS
Long-nosed Echidna MONOTREMATA; TACHYGLOSSIDAE; ZAGLOSSUS
Griffiths M 1978. The Biology of the Monotremes. Academic Press, New York.
Griffiths M 1989. Tachyglossidae. In: "Fauna of Australia". Eds.
Griffiths, M., 1988. The Platypus. Scientific American. 258(5), pp.84-91.
Grant, T.R., & Griffiths, M., & Leckie, R.M.C., 1983. Aspects of lactation in the platypus, Ornithorhynchus anatinus (Monotremata), in waters of eastern New South Wales. Australian Journal of Zoology. 31, pp.881-889.