Myrmecophagidaeanteaters

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Four species in three genera make up this family, whose members are found in Central and South America.

Anteaters range from the very small Cyclopes, which weighs around 250 gms, to the large Myrmecophaga, which weighs over 30 kg. All anteaters have long, tapered snouts; that of Myrmecophaga is extraordinarily elongated. The tongue is also long. Anteaters secrete a sticky substance from their salivary glands that coats the tongue when they feed. The ears are small and rounded, and the eyes are small. The tails are long and prehensile in 2 of the 3 genera. The forelimbs are remarkable. They have 5 digits, each with long and sharp claws, the third claw being especially well developed. The hind feet are less specialized, with 4 or 5 toes and strong but not remarkable claws. Myrmecophaga walks with a peculiar, shuffling gait; Tamandua species walk on the sides of their hands; and Cyclopes are almost exclusively arboreal. The body fur varies from coarse and long (Myrmecophaga) to short, soft, and silky (Cyclopes). All species have some sort of contrasting color pattern.

Besides its extreme elongation, the skull of anteaters is remarkable because it completely lacks teeth. The jugal is small or absent, and the zygomatic arch is incomplete. The premaxillae are small, but the the lacrimals are large and well developed. The palate is very long; its posterior margin is extended by the fusion of the pterygoids in some species. The mouth opening is tubular and very small. The mandibles are long, thin, and weak.

Anteaters feed almost exclusively on ants and termites, whose nests they rip open with their powerful forelimbs. They also take some beetle larvae and bees, and in captivity giant anteaters accept some fruit. The prey of anteaters adheres to their long, sticky tongues. It is swallowed, and part of the digestive process involves grinding by the unusually muscular pyloric region of the stomach. Cyclopes forages arboreally; Tamandua on the ground or in trees, and Myrmecophaga strictly on the ground.

These animals are not gregarious; they come together primarily for the purpose of breeding. The foreclaws of the larger species are highly effective defensive weapons against predators. Giant anteaters forage during day and night; the other species are most often nocturnal or crepuscular. All anteaters have an excellent sense of smell; sight and hearing are not as well developed.

Geologically, the family is known only back to the Early Miocene in South America. The record is poor, however, and the group is likely to be older.

Literature and references cited

Barlow, J. C. 1984. Xenarthrans and pholidotes. Pp. 219-239 in Anderson, S. and J. K. Jones, Jr. (eds). Orders and Families of Recent Mammals of the World. John Wiley and Sons, N.Y. xii+686 pp.

Paradiso, J. L. 1975. Walker's Mammals of the World, Third Edition. Johns Hopkins University Press, Baltimore.

Savage, R. J. G. and M. R. Long. 1986. Mammal Evolution, an Illustrated Guide. Facts of File Publications, New York. 259 pp.

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

Wilson, D. E., and D. M. Reeder. 1993. Mammal Species of the World, A Taxonomic and Geographic Reference. 2nd edition. Smithsonian Institution Press, Washington. xviii+1206 pp.

Contributors

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