Anteater

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Anteater
Temporal range: Early Miocene-present
Myresluger2.jpg
Giant anteater
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Pilosa
Suborder:Vermilingua
Illiger, 1811
Families

Cyclopedidae
Myrmecophagidae

Anteater is a common name for the four extant mammal species of the suborder Vermilingua [1] (meaning "worm tongue") commonly known for eating ants and termites. [2] The individual species have other names in English and other languages. Together with the sloths, they are within the order Pilosa. The name "anteater" is also colloquially applied to the unrelated aardvark, numbat, echidnas, pangolins and some members of the Oecobiidae.

In biology, a common name of a taxon or organism is a name that is based on the normal language of everyday life; this kind of name is often contrasted with the scientific name for the same organism, which is Latinized. A common name is sometimes frequently used, but that is by no means always the case.

Neontology is a part of biology that, in contrast to paleontology, deals with living organisms. It is the study of extant taxa : taxa with members still alive, as opposed to (all) being extinct. For example:

Mammal class of tetrapods

Mammals are vertebrate animals constituting the class Mammalia, and characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Triassic, 201–227 million years ago. There are around 5,450 species of mammals. The largest orders are the rodents, bats and Soricomorpha. The next three are the Primates, the Cetartiodactyla, and the Carnivora.

Contents

Extant species are 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.

Giant anteater A large insectivorous mammal native to Central and South America

The giant anteater, also known as the ant bear, is an insectivorous mammal native to Central and South America. It is one of four living species of anteaters, the only extant member of the genus Myrmecophaga, and is classified with sloths in the order Pilosa. This species is mostly terrestrial, in contrast to other living anteaters and sloths, which are arboreal or semiarboreal. The giant anteater is the largest of its family, 182 to 217 cm in length, with weights of 33 to 41 kg for males and 27 to 39 kg for females. It is recognizable by its elongated snout, bushy tail, long fore claws, and distinctively colored pelage.

Silky anteater A species of mammals related to sloths and armadillos

The silky anteater, also known as the pygmy anteater, is a species of anteater in the genus Cyclopes, the only living genus in the family Cyclopedidae. It is found in southern Mexico, and Central and South America. A taxonomic review in 2017, including both molecular and morphological evidence, found that Cyclopes may comprise not one species, as previously thought, but at least seven. The only known extinct cyclopedid species, Palaeomyrmidon incomtus, from the Late Miocene of Argentina, is thought to share common ancestry with Cyclopes. It is the smallest of all known anteaters, has nocturnal habits and appears to be completely arboreal. Its hind feet are highly modified for climbing.

Southern tamandua A species of mammals related to sloths and armadillos

The southern tamandua, also called the collared anteater or lesser anteater, is a species of anteater from South America. It is a solitary animal, found in many habitats from mature to highly disturbed secondary forests and arid savannas. It feeds on ants, termites, and bees. Its very strong fore claws can be used to break insect nests or to defend itself.

Taxonomy

Classification

The four extant species of anteater
Myrmecophaga tridactyla - Phoenix Zoo.jpg
Giant anteater
Two-toed anteater balanced on a stick.jpg
Silky anteater
Lesser Anteater.jpg
Southern tamandua
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Northern tamandua

The anteaters are more closely related to the sloths than they are to any other group of mammals. Their next closest relations are armadillos. There are four extant species in three genera:

Armadillo family of mammals

Armadillos are New World placental mammals in the order Cingulata. The Chlamyphoridae and Dasypodidae are the only surviving families in the order, which is part of the superorder Xenarthra, along with the anteaters and sloths. Nine extinct genera and 21 extant species of armadillo have been described, some of which are distinguished by the number of bands on their armour. All species are native to the Americas, where they inhabit a variety of different environments.

There are several extinct genera as well.

Order Pilosa

Sloth tree dwelling animal noted for slowness

Sloths are arboreal mammals noted for slowness of movement and for spending most of their lives hanging upside down in the trees of the tropical rainforests of South America and Central America. The six species are in two families: two-toed sloths and three-toed sloths. In spite of this traditional naming, all sloths actually have three toes. The two-toed sloths have two digits, or fingers, on each forelimb.

Cyclopedidae monotypic family of anteaters

The Cyclopedidae is a family of anteaters that includes the silky anteater and its extinct relative, Palaeomyrmidon.

Palaeomyrmidon is an extinct genus of anteater. Its closest living relative is the silky anteater. Although the silky anteater is arboreal, Palaeomyrmidon lived on the ground. Palaeomyrmidon is known from a fossil skull that was found in the Andalhualá Formation of Argentina.

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, anteaters were assumed to be related to aardvarks and pangolins because of their physical similarities to those animals, but these similarities have since been determined to be not a sign of a common ancestor, but of convergent evolution. All have evolved powerful digging forearms, long tongues, and toothless, tube-like snouts to subsist 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.

Physical characteristics

Giant anteater skeleton with visible "knuckle-walking" forelimbs Myrmecophaga tridactyla skeleton.jpg
Giant anteater skeleton with visible "knuckle-walking" forelimbs

All anteaters have elongated snouts equipped with a thin tongue that can be extended to a length greater than the length of the head; their tube-shaped mouths have lips but no teeth. They use their large, curved foreclaws to tear open ant and termite mounds and for defense, while their dense and long fur protects them from attacks from the insects. All species except the giant anteater have a long prehensile tail. [6]

Behaviour

Sleeping giant anteater AnteaterAsleep.JPG
Sleeping giant anteater

Anteaters are mostly solitary mammals prepared to defend their 1.0- to 1.5-mi2 (2.6- to 3.9-km2) territories. They do not normally 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. [6]

Anteaters have poor sight but an excellent sense of smell, and most species depend on the latter for foraging, feeding, and defence. Their hearing is thought to be good. [6]

With a body temperature fluctuating between 33 and 36 °C (91 and 97 °F), anteaters, like other xenarthrans, have among the lowest body temperatures of any mammal, [7] 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 temperatures so they keep cool during periods of rest, and heat up during foraging. [6]

Reproduction

Adult males are slightly larger and more muscular than females, and have wider heads and necks. 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. [6]

Feeding

Anteaters are specialized to feed on small insects, with each anteater species having its own 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 of licking up large numbers of ants and termites as quickly as possible — an anteater normally spends about a minute at a nest before moving on to another — and a giant anteater has to visit up to 200 nests per hour to consume the thousands of insects it needs to satisfy its caloric requirements. [6]

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 are aided by side-to-side movements of the jaws. The tongue is attached to the sternum and moves very quickly, flicking 150 times per minute. The anteater's stomach, similar 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. [6]

Distribution

Range

Silky anteaters and northern tamanduas extend their ranges as far north as southeastern Mexico, while giant anteaters can be found as far north as Central America. Southern tamanduas range south to Uruguay (giant anteaters did also until their recent extirpation there) and the ranges of all species except the northern tamandua overlap in eastern Brazil. Anteaters were confined to South America, which was formerly an island continent, during most of the Cenozoic Era. Once the Isthmus of Panama formed about three million years ago, however, anteaters invaded Central America as part of the Great American Interchange.

Habitat

Anteater habitats include dry tropical forests, rainforests, grasslands, and savannas. The silky anteater (Cyclopes didactylus) is specialized to an arboreal environment, but the more opportunistic tamanduas 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) lives in savannas. [6]

The two anteaters of the genus Tamandua , the southern (Tamandua tetradactyla) and the northern tamanduas (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. [8]

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. [8]

Notes

  1. "Giant Anteater Facts". Smithsonian Institution. Archived from the original on 2011-08-28. Retrieved 2011-07-30.
  2. "Giant Anteater". Canadian Museum of Nature. Archived from the original on 19 July 2011. Retrieved 2011-07-30.
  3. "Palaeomyrmidon". Paleobiology Database. Archived from the original on 30 July 2013. Retrieved 4 February 2012.
  4. "Neotamandua". Paleobiology Database. Retrieved 4 February 2012.
  5. "Protamandua". Paleobiology Database. Retrieved 4 February 2012.
  6. 1 2 3 4 5 6 7 8 Grzimek 2004 , pp. 171–175
  7. Lovegrove, B. G. (August 2000). "The Zoogeography of Mammalian Basal Metabolic Rate". The American Naturalist. The University of Chicago Press. 156 (2): 201–219, see 214–215. doi:10.1086/303383. JSTOR   3079219. PMID   10856202.
  8. 1 2 Wikisource-logo.svg One or more of the preceding sentences incorporates text from a publication now in the public domain : Chisholm, Hugh, ed. (1911). "Anteater"  . Encyclopædia Britannica . 2 (11th ed.). Cambridge University Press. p. 89.

Related Research Articles

Xenarthra Superorder of mammals that diversified in South America

Xenarthra is a superorder of placental mammals found in the Americas. It currently consists of anteaters, tree sloths and armadillos. Xenarthrans originated in South America during the Paleocene about 59 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era. They spread to the Antilles by the early Miocene and, starting about 3 Mya, spread to Central and North America as part of the Great American Interchange. Nearly all of the formerly abundant megafaunal xenarthrans, such as ground sloths, glyptodonts and pampatheres, became extinct at the end of the Pleistocene.

Pilosa order of mammals

The order Pilosa is a group of placental mammals, extant today only in the Americas. It includes the anteaters and sloths, including the extinct ground sloths, which became extinct about 10,000 years ago. The name comes from the Latin word for "hairy". Pilosans are good examples of ecological harmony. Anteaters, for example, feed lightly and for a short time at any one ant nest, allowing the colony to regrow easily. Also, sloths' fur is home to many insects, as well as a type of algae that helps camouflage the sloths.

"Anteater" properly refers to the four species of the suborder Vermilingua native to Mexico, Central America, and tropical South America. This includes two species of Tamandua and the Giant Anteater.

The mammalian order Pilosa, which includes the sloths and anteaters, includes various species from the Caribbean region. Many species of sloths are known from the Greater Antilles, all of which became extinct over the last millennia, but some sloths and anteaters survive on islands closer to the mainland.

Juruá-Purus moist forests

The Juruá-Purus moist forests (NT0133) is an ecoregion in northwest Brazil in the Amazon biome. The terrain is very flat and soils are poor. The rivers flood annually. There are no roads in the region, and the dense rainforest is relatively intact, although plans to extend the Trans-Amazonian Highway through the region would presumably cause widespread damage to the habitat.

References