Anteater

For other uses, see Anteater (disambiguation).

Anteater
Giant Anteater
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Superorder:	Xenarthra
Order:	Pilosa
Suborder:	Vermilingua Illiger, 1811
Families
Cyclopedidae Myrmecophagidae

Anteaters, also known as antbear, are the four mammal species of the suborder Vermilingua (meaning "worm tongue") commonly known for eating ants and termites. Together with the sloths, they compose the order Pilosa. The name "anteater" is also colloquially applied to the unrelated aardvark, numbat, echidnas, and pangolins.

Extant species comprise the Giant Anteater Myrmecophaga tridactyla, about 1.8 m (5 ft 11 in) long including the tail; the Silky Anteater Cyclopes didactylus, about 35 cm (14 in) long; the Southern Tamandua or Collared Anteater Tamandua tetradactyla, about 1.2 m (3 ft 11 in) long; and the Northern Tamandua Tamandua mexicana of similar dimensions.

Classification

The Anteaters are more closely related to the sloths than they are to any other group of mammals, even to the armadillos, their next closest relations. There are three genera still living: the Giant Anteater, the Silky Anteater, and the Northern and Southern Tamandua anteaters, but there are also several extinct genera.

A giant anteater (top), a silky anteater, and a southern tamandua

Order Pilosa

• Suborder Folivora (sloths)
• Suborder Vermilingua (Anteaters)
  • Family Cyclopedidae
    • Genus Cyclopes
      • Silky Anteater (C. didactylus)
    • Genus †Palaeomyrmidon (Rovereto 1914)
  • Family Myrmecophagidae
    • Genus Myrmecophaga
      • Giant Anteater (M. tridactyla)
    • Genus †Neotamandua (Rovereto 1914)
    • Genus Tamandua
      • Northern Tamandua (T. mexicana)
      • Southern Tamandua (T. tetradactyla)
    • Genus †Protamandua (Ameghino 1904)

Physical characteristics

Gian Anteater skeleton with visible "knuckle-walking" forelimbs

All anteaters have an elongated snout equipped with a thin tongue that can be extended to a length greater than the length of the head; their tube-shaped mouth have lips but no teeth. They use their large, curved foreclaws to tear open ant and termite mounds and for defence, while their dense and long fur protects them from attacks from the insects. All species except the Giant Anteater have a prehensile tail.

Behavior

Sleeping Giant Anteater

Anteaters are mostly solitary mammals prepared to defend their 1 to 1.5 square miles (2.6 to 3.9 km²) territories. Normally, they do not enter a territory of another anteater of the same sex, but males often enter the territory of associated females. When a territorial dispute occurs, they vocalize, swat, and can sometimes sit on or even ride the back of their opponents.

Anteaters have a poor sense of sight but and excellent sense of smell, and most species depend on the latter for foraging, feeding, and defence. Their sense of hearing is thought to be good.

With a body temperature fluctuating between 33–36 °C (91–97 °F), anteaters have the lowest body temperature of any mammal and can tolerate greater fluctuations in body temperature than most mammals. Its daily energy intake from food is only slightly greater than its energy need for daily activities, and anteaters probably coordinate their body temperature so that they keep cool during periods of rest and heat up during foraging.

Reproduction

Adult males are slightly larger and more muscular than females, and have wider heads and neck. Visual sex determination can, however, be difficult since the penis and testes are located internally between the rectum and urinary bladder in males and females have a single pair of mammae near the armpits. Fertilization occurs by contact transfer without intromission similar to some lizards. Polygynous mating usually results in a single offspring, twins are possible but rare. The large foreclaws prevent mothers from grasping their newborns and they therefore have to carry the offspring until they are self-sufficient.

Feeding

Anteaters are specialized to feed on ants and termites, each anteater species having its own preferred insect preferences: small species are specialized on arboreal insects living on small branches while large species can penetrate the hard covering of the nests of terrestrial insects. To avoid the jaws, sting, and other defences of the invertebrates, anteaters have adopted the feeding strategy to lick up as many ants and termites as quickly as possible — an anteater normally spends about a minute at a nest before moving on to the another — and a giant anteater has to visit up to 200 nests to consume the thousands of insects it needs to satisfy its caloric requirements.

The anteater's tongue is covered with thousands of tiny hooks called filiform papillae which are used to hold the insects together with large amounts of saliva. Swallowing and the movement of the tongue is aided by side to side movements of the jaws. The anteater's stomach, similarly to a bird's gizzard, has hardened folds and uses strong contractions to grind the insects; a digestive process assisted by small amounts of ingested sand and dirt. The tongue is attached to the sternum and moves very quickly, flicking 150 times per minute.

Distribution

Two species of anteaters extend their ranges as far north as South-eastern Mexico; while the other two can be found up to Central America. The ranges of two species extend south to Uruguay and the ranges of three species overlap in eastern Brazil.

Habitat

Anteater habitat includes dry tropical forests, rainforests, grasslands, and savannas. The silky anteater (Cyclopes didactylus) is specialized to an arboreal environment, but the more opportunistic tamandua find their food both on the ground and in trees, typically in dry forests near streams and lakes. The almost entirely terrestrial giant anteater (Myrmecophaga tridactyla) live in savannas.

The two Anteaters of the genus Tamandua, the Southern Tamandua (Tamandua tetradactyla) and the Northern Tamandua (Tamandua mexicana), are much smaller than the Giant Anteater, and differ essentially from it in their habits, being mainly arboreal. They inhabit the dense primeval forests of South and Central America. The usual colour is yellowish-white, with a broad black lateral band, covering nearly the whole of the side of the body.

The silky Anteater (Cyclopes didactylus) is a native of the hottest parts of South and Central America, and about the size of a cat, of a general yellowish color, and exclusively arboreal in its habits.

Evolution

Anteaters are one of three surviving families of a once diverse group of mammals that occupied South America while it was geographically isolated from an invasion of animals from North America, the other two being the sloths and the armadillos.

At one time, it was assumed that anteaters were related to aardvarks and pangolins because of their physical similarities to those animals, but it has since been determined that these similarities are not a sign of a common ancestor, but of convergent evolution. All have evolved powerful digging forearms and long tongues and toothless tube-like snouts in order to make a living by raiding termite mounds. This similarity is the reason aardvarks are also commonly called "anteaters"; the pangolin has been called the "scaly anteater"; and the word "antbear" is a common term for both the aardvark and the giant anteater.

References

• Grzimek, Bernhard (2004). Hutchins, Michael; Kleiman, Devra G; Geist, Valerius et al. eds. Grzimek's Animal Life Encyclopedia. 13 (2nd ed.). Detroit: Gale. pp. 171-179. ISBN 0-7876-7750-7. 
•  Chisholm, Hugh, ed. (1911). "Anteater". Encyclopædia Britannica (11th ed.). Cambridge University Press.