Tachyglossidaeechidnas(Also: spiny anteaters)

This family includes two genera and 4 species. Zaglossus, long-beaked echidnas, are found in New Guinea and Tachyglossus, short-beaked echidna, is native to Australia. Echidnas have spines covering their stout bodies. They curl up into a spine-covered ball in a rather effective method of defense. Echidnas are powerful diggers and can wedge themselves into a burrow or crevice with their spines so that they are difficult to remove.

In general, echidnas dig for food, which consists of termites, ants, and assorted invertebrates. Food is located with the help of special electroreceptors located in the rostrum. Echidnas have long, protrusible, mucous-covered tongues that aid in the capture of prey. The sticky mucous coating is produced by enlarged submaxillary salivary glands. Spines at the base of the tongue grind against spiny ridges on the palate to masticate food.

Echidnas are moderately large animals (up to 16 kg for Zaglossus). They have narrow, slender snouts, not at all expanded like that of platypuses. Their skeletons are heavily built, perhaps to accomodate the powerful muscles used for digging. Unlike platypuses, echidnas lack webbing and instead have large, shovel-like claws are present on all feet. Spurs, the function of which is unclear, are located on the ankles of all males and some females.

Echidnas lay a single leathery egg that is kept in the pouch 7-10 days, until the young hatches. The young remains in the pouch another 6-8 weeks, until its spines begin to harden.

References and literature cited

Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. Adaptation, Diversity, and Ecology. WCB McGraw-Hill, Boston. xii+563pp.

Marshall, L. G. 1984. Monotremes and marsupials. Pp. 59-115 in Anderson, S. and J. Knox Jones, Jr., eds. Orders and Families of Recent Mammals of the World. John Wiley & Sons, New York. xii+686 pp.

Vaughan, T. A. 1986. Mammalogy. Third Edition. Saunders College Publishing, Fort Worth. vi+576 pp.

Vaughan, T. A., J. M. Ryan, N. J. Czaplewski. 2000. Mammalogy. Fourth Edition. Saunders College Publishing, Philadelphia. vii+565pp.

Contributors

Anna Bess Sorin (author), Biology Dept., University of Memphis, Phil Myers (author), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

motile

having the capacity to move from one place to another.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate