Giant Anteater

Giant Anteater[1]
Conservation status
Vulnerable (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Superorder:	Xenarthra
Order:	Pilosa
Suborder:	Vermilingua
Family:	Myrmecophagidae
Genus:	Myrmecophaga Linnaeus, 1758
Species:	M. tridactyla
Binomial name
Myrmecophaga tridactyla Linnaeus, 1758
Giant Anteater range (blue — extant, orange — possibly extinct)

The Giant Anteater, Myrmecophaga tridactyla, is the largest species of anteater. It is the only species in the genus Myrmecophaga. It is found in Central and South America from Honduras to northern Argentina.^[2] Its fossil remains have been found as far north as northwestern Sonora, Mexico.^[3]

It is a solitary animal, found in many habitats, including grasslands, deciduous forests and rainforests. It feeds mainly on ants and termites, sometimes up to 30,000 insects in a single day.

The genus name Myrmecophaga is from Greek murmekos, ant, and phagein, to eat.

Physiology

The giant anteater is one of few taxa of mammals without any teeth even in a mature state. An anteater instead crushes insects it consumes using hard growths found on the inside of its mouth, and its flabby stomach. Sand and small rocks have also been found in anteaters' stomachs, suggesting that these are ingested to aid digestion (possible gastroliths). They have an average body temperature of 32.7^oC, which is one of the lowest of all land-living mammals. This low rate of metabolism, common in xenarthrans, means it is inactive for a mammal.^[4] Unlike most mammals, the giant anteater's gastric acid does not contain hydrochloric acid; rather, it uses formic acid produced by its prey.^[5]

It grows to a size of up to 7 feet (2.1 m) in length, with a 4-foot-long (1.2 m) head and torso, and a 3-foot-long (0.91 m) tail. Generally it weighs from 65 to 140 pounds (29 to 64 kg).

The giant anteater is covered with stiff, straw-like hair which grows up to 40 cm long on the tail. Young have soft hair until they are mature. The dominant colouring may be grey or brown, but all have a diagonal black and white shoulder stripe.

The giant anteater is generally acknowledged to have a very keen sense of smell, used to locate ants, but is thought to have poor sight and hearing.

The giant anteater does not sleep in any fixed place, instead curling up in abandoned burrows and hollows. It covers its body with its long, bushy tail to sleep.

In the wild, it is nocturnal (or active at night) near human settlements, and diurnal (active during the day) elsewhere. It stays mainly on dry ground but is a strong and capable swimmer.

When threatened it does not flee, but stands up on its hind legs, using its tail to aid balance, and sometimes strikes extremely rapidly with its claws or "hugs" attackers much like a bear. An adult anteater is capable of fending off or even killing its main predators, big cats such as the jaguar and the cougar.

Anatomy

skeleton showing forelimbs resting on their knuckles

Despite its name, Myrmecophaga tridactyla, from the Greek meaning 'three-fingered ant eater', the anteater has five digits on each foot; however the middle three digits of the forefeet have elongated claws. These are extremely strong and are used to break open ant and termite mounds in order to feed, and provide effective defense against predators. The anteater walks on its knuckles in order to protect them, giving it a shuffling gait. Their wrist bones are adapted for knuckle-walking in much the same way as those of chimpanzees.^[6] The forefeet also have one other smaller claw, and the rear feet have five small claws.

The anteater's tongue can reach 2 feet (61 cm) in length, but has a width of only ¹⁄₂ inch (13 mm). The anteater can cover its tongue in a sticky saliva, allowing it to trap ants, and can extend and withdraw it up to 150 times per minute. Pangolins, the giant anteater, and the tube-lipped nectar bat all have developed tongues which are detached from their hyoid bone and extend past their pharynx deep into the thorax, an example of convergent evolution.^[7] This extension lies between the sternum and the trachea.

Reproduction

Giant anteater with offspring clinging to her back.

It bears a single offspring after a gestation period of 190 days, which will stay near the mother until she becomes pregnant again. The baby spends much of the first part of its life riding on its mother's back, until it is nearly half her size.

The mating system of M. tridactyla is not well known. Reproductive behavior is primarily observed in captivity^{[citation needed]}.

Gestation is approximately 190 days, after which females give birth to a single young that weighs about 2.8 lb (1.3 kg). Females give birth standing up and the newborn anteater immediately climbs onto her back. Young are born with a full coat of hair and adult-like markings. Breeding occurs year-round in captivity and the wild, though seasonal breeding times have been reported in portions of their range. Inter-birth intervals can be as low as nine months. Sexual maturity is reached between 2.5 and 4 years. The mammary glands are lateral to the 'armpits' on the chest.

• Breeding interval: Giant anteaters can breed as often as every 9 months, though it is often longer.
• Breeding season: Giant anteaters may breed year round, or seasonally depending on region.
• Number of offspring: 1 (average)
• Gestation period: 190 days (average)
• Time to weaning: 6 months (average)
• Time to independence: 24 months (average)
• Age at sexual or reproductive maturity (female): 2.50 to 4 years
• Age at sexual or reproductive maturity (male): 2.50 to 4 years

Communication and perception

Most communication occurs between young and their mothers or during fighting. It consists of snorts, sniffs, and hisses, as well as roaring during fights. They have rather poor sight and hearing.

Food habits

Giant anteaters eat ants, termites and soft-bodied grubs. Using the long, sharp claws on their forelimbs, they open insect colonies and tree trunks. They then use the tongue to collect the eggs, larvae, and adult insects. The salivary glands secrete sticky saliva during feeding that coats the tongue. They only stay at one ant colony for a short period of time to avoid soldier ants, but giant anteaters can consume a few thousand insects in minutes. The tongue is attached to the sternum and moves very quickly, flicking 150 times per minute. They will eat fruit and birds' eggs on occasion.

Threats

Illustration of an anteater attacked by a cougar

The jaguar (Panthera onca) and the cougar (Puma concolor) are known predators of giant anteaters. Anteaters use their immense front claws to defend themselves from predators, but their typical response to threat is to run away Verify: This contradicts statement in paragraph 7 of "physiology" heading. Their size makes them invulnerable to all but the largest of predators, jaguars and cougars primarily. They are often killed by humans, either intentionally through hunting or unintentionally through collisions with cars. In April 2007, an anteater at the Florencio Varela Zoo near Buenos Aires, Argentina attacked Melisa Casco, a zookeeper, mauling her abdomen and legs with its sharp front claws. The 19-year old zookeeper was admitted to the hospital in critical condition and died following leg amputation surgery.^[8]

Conservation status

Habitat destruction is the primary threat to giant anteaters. They are listed as Appendix II by the Convention on International Trade in Endangered Species (CITES). Appendix II is defined as a species not necessarily threatened to extinction but one that should be controlled in trade to avoid overuse. They are listed as vulnerable by the International Union for Conservation of Nature and Natural Resources (IUCN). 'Vulnerable' is defined as an estimated population reduction of 20% in the next 10 years. It is estimated that there are only as few as 5,000 left in the wild, and only 90 live in zoos across the United States.

References

1. ^ Gardner, Alfred L. (16 November 2005). "Order Pilosa (pp. 100-103)". In Wilson, Don E., and Reeder, DeeAnn M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). p. 102. ISBN 978-0-8018-8221-0. OCLC 62265494. http://www.bucknell.edu/msw3/browse.asp?id=11800038. 
2. ^ ^{a b} Miranda, F. & Medri, I. M. (2010.0). "Myrmecophaga tridactyla". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/14224. Retrieved 04 November 2010. 
3. ^ Shaw, C. A.; McDonald, H. G. (1987-04-10). "First Record of Giant Anteater (Xenarthra, Myrmecophagidae) in North America". Science (AAAS) 236 (4798): 186–188. doi:10.1126/science.236.4798.186. JSTOR 1698387. PMID 17789783. 
4. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
5. ^ ANTEATERS at the Natural History Collection of the University of Edinburgh
6. ^ Orr CM. (2005). "Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae". Am J Phys Anthropol 128 (3): 639–58. doi:10.1002/ajpa.20192. PMID 15861420. 
7. ^ Muchhala N. (2006). "Nectar bat stows huge tongue in its rib cage". Nature 444 (7120): 701. Bibcode 2006Natur.444..701M. doi:10.1038/444701a. 
8. ^ "Argentine zookeeper dies after anteater attack". Reuters. 2007-04-12. http://www.reuters.com/article/worldNews/idUSN1235848120070412. Retrieved 2007-04-13. 

• Louise H. Emmons and Francois Feer, 1997 – Neotropical Rainforest Mammals, A Field Guide.

External links

• The Online Anteater: information, images, fun facts, and other stuff about the giant anteater
• ARKive – images and movies of the giant anteater.

Gallery

At Reid Park Zoo, Tucson, Arizona   Dictionary illustration   In San Francisco Zoo   Giant Anteater in captivity in Ueno Zoo in Japan (video)   Giant Anteater (Myrmecophaga tridactyla) in the Pantanal Region, Brazil