Where do anteaters live? It depends on how you define 'anteater'| ECOVIEWS

Q. A friend says anteaters occur on five continents (all but Europe and Antarctica). According to my biology teacher, anteaters are only found in the Western Hemisphere. Who’s right? I can’t figure this out with Internet research.

A. Both are correct depending on the definition used.

If you call all long-nosed mammals that eat ants (and termites) anteaters, they are indeed found on the five continents you refer to.

However, your teacher is using the restrictive scientific definition of the four “true” anteaters. These share a common ancestry evolutionarily and are more closely related to each other than to any other group of animals. All four occur in South America; two of them reach as far north as Mexico. Their closest relatives are the sloths of Central and South American tropical rainforests.

The silky anteater is the smallest, with an average body length of little more than a foot and a weight of less than 1 pound. Silky anteaters, which some geneticists consider to represent several species, have an extensive geographic range, from Bolivia to southern Mexico. Active mostly at night, they are arboreal, traveling from tree to tree in search of ants and other insects. Silky anteaters will defend themselves by standing up on their hind legs and confronting the threat with their long claws.

The largest species, aptly known as the giant anteater, reaches lengths of more than 6 feet and can weigh more than 100 pounds. It has no teeth but efficiently gathers ants and termites with its 2-foot-long tongue. It is the only truly terrestrial anteater of tropical America.

Although giant anteaters are still found in many forest and grassland habitats from Argentina to Honduras, their plight mirrors that faced by so many of the world’s wildlife species today. They are no longer present in some countries, including Guatemala and Uruguay, where they once were common. Destruction of their habitat and unregulated poaching are two major reasons for their decline.

The other two true anteaters are intermediate in size compared to the silky and giant anteaters. They are similar to them in morphology, behavior and habitats. These two anteaters are commonly referred to as the southern tamandua and the northern tamandua, which also occurs in southern Mexico. The term “tamandua” is derived from the language of the Tupi, indigenous people of Brazil.

Other animals often called anteaters are not closely related to the American anteaters or to each other, although they have similar diets of ants and termites.

The spiny anteaters of Australia and New Guinea are the most disparate evolutionarily from any of the others. They belong to an entirely different group of animals known as the monotremes, which are egg-laying mammals. Their closest relative is the duckbill platypus. Another name for a spiny anteater is echidna.

The banded anteater, another mammal native to Australia, is sometimes referred to as the numbat. A marsupial, the numbat is more closely related to kangaroos and the extinct Tasmanian tiger than to spiny anteaters.

The aardvark, or Cape anteater, occurs in the southern half of Africa and is the only living species in its taxonomic group. Its head looks like a cross between a pig and a jackrabbit. Aardvarks are related to elephants and manatees. Like other anteaters they have huge claws for digging up ant and termite nests.

Pangolins, also called scaly anteaters, include eight species, of which half are found in Africa and half in Asia. These comprise the only members of a distinct family of mammals that have a covering of armored plates on their body. Long claws coupled with a long nose and tongue are part of their toolkit for digging out and eating their favored prey of ants and termites.

All anteaters, whether you take the global definition or the more restrictive Western Hemisphere one, are fascinating creatures. And as with any aspect of the natural world, the more you learn about the plant or animal the more interested you are in its preservation. A win-win.

Whit Gibbons is professor of zoology and senior biologist at the University of Georgia’s Savannah River Ecology Laboratory. If you have an environmental question or comment, email ecoviews@gmail.com.

This article originally appeared on The Tuscaloosa News: Where do anteaters live? Depends on how you define 'anteater'| ECOVIEWS