The Giant Anteater (Myrmecophaga tridactyla) is an insectivorous mammal native to Central and South America. It is one of four living species of anteaters, of which it is the largest member. The only extant member of the genus Myrmecophaga, it 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 182 to 217 cm (5 ft 11+1⁄2 in to 7 ft 1+1⁄2 in) in length, with weights of 33 to 50 kg (73 to 110 lb) for males and 27 to 47 kg (60 to 104 lb) for females. It is recognizable by its elongated snout, bushy tail, long fore claws, and distinctively colored pelage.

The giant anteater is found in multiple habitats, including grassland and rainforest. It forages in open areas and rests in more forested habitats. It feeds primarily on ants and termites, using its fore claws to dig them up and its long, sticky tongue to collect them. Though giant anteaters live in overlapping home ranges, they are mostly solitary except during mother-offspring relationships, aggressive interactions between males, and when mating. Mother anteaters carry their offspring on their backs until weaning them.

The giant anteater is listed as vulnerable by the International Union for Conservation of Nature. It has been extirpated from many parts of its former range. Threats to its survival include habitat destruction, fire, and poaching for fur and bushmeat, although some anteaters inhabit protected areas. With its distinctive appearance and habits, the anteater has been featured in pre-Columbian myths and folktales, as well as modern popular culture.

The giant anteater got its binomial name from Carl Linnaeus in 1758. Its generic name, Myrmecophaga, and specific name, tridactyla, are both Greek, meaning "anteater" and "three fingers", respectively. Myrmecophaga jubata was used as a synonym. Three subspecies have been suggested: M. t. tridactyla (Venezuela and the Guianas south to northern Argentina), M. t. centralis (Central America to northwestern Colombia and northern Ecuador), and M. t. artata (northeastern Colombia and northwestern Venezuela). The giant anteater is grouped with the semiarboreal northern and southern tamanduas in the family Myrmecophagidae. Together with the family Cyclopedidae, whose only extant member is the arboreal silky anteater, the two families comprise the suborder Vermilingua.

Anteaters and sloths belong to order Pilosa and share superorder Xenarthra (cladogram below) with the Cingulata (whose only extant members are armadillos). The two orders of Xenarthra split 66 million years ago (Mya) during the Late Cretaceous epoch. Anteaters and sloths diverged around 55 Mya, between the Paleocene and Eocene epochs. The lineages of Cyclopes and other extant anteaters split around 40 Mya in the Oligocene epoch, while the last common ancestor of Myrmecophaga and Tamandua existed 10 Mya in the Late Miocene subepoch.[8] Though most of their evolutionary history, anteaters were confined to South America, which was formerly an island continent. Following the formation of the Isthmus of Panama about 3 Mya, anteaters of all three extant genera invaded Central America as part of the Great American Interchange.

The giant anteater can be identified by its large size, long, narrow muzzle, and long bushy tail. It has a total body length of 182 to 217 cm (5 ft 11+1⁄2 in to 7 ft 1+1⁄2 in). Males weigh 33 to 50 kg (73 to 110 lb) and females weigh 27 to 47 kg (60 to 104 lb), making the giant anteater the biggest extant species in its suborder. The head of the giant anteater, at 30 cm (12 in) long, is particularly elongated, even when compared to other anteaters. Its cylindrical snout takes up most of its head. Its eyes, ears and mouth are relatively small. It has poor eyesight, but has a powerful sense of smell; 40 times that of a human. While there is some difference in size and shape between the sexes, males being larger and more robust, telling them apart from a distance can be difficult. The male's genitals are located within its body and upon closer examination, its uno-genital opening is smaller and farther from the anus. The female's two mammary glands are located between the front legs.

Even for an anteater, the neck is especially thick compared to the back of the head, and a small hump is protrudes behind the neck. The coat is mostly greyish, brown or black with mottled white. They have white front legs, with black ringed wrists and hands, and dark hind legs. From the throat to the shoulders is a thick black mark with white outlines and sharp tips. The body ends in a brown tail. The coat hairs are long, especially on the tail, which makes the tail look larger than it actually is. An erect mane stretches along the back. The bold pattern was thought to be disruptive camouflage, but a 2009 study suggests it is warning coloration.

The giant anteater has broad ribs. It has five toes on each foot. Three toes on the front feet have claws, which are particularly large on the third digits.[22] It walks on its front knuckles similar to gorillas and chimpanzees. This allows the giant anteater to walk without scraping its claws on the ground, keeping them sharp. The middle digits, which support most of its weight, have long metacarpophalangeal joints and bent interphalangeal joints. Unlike the front feet, the hind feet have short claws on all five toes and walk plantigrade. As a "hook-and-pull" digger, the giant anteater has a large supraspinous fossa which gives the teres major more leverage—increasing the front limbs' pulling power—and the triceps muscle helps control the thickened middle digit.

The giant anteater has a low body temperature for a mammal, about 33 °C (91 °F), a few degrees lower than a typical mammalian temperature of 36 to 38 °C (97 to 100 °F). Xenarthrans in general tend to have lower metabolic rates than most other mammals, a trend thought to correlate with their dietary specializations and low mobility.

The giant anteater has no teeth and is capable of only very limited jaw movement. It relies on the rotation of the two halves of its lower jaw, held together by a ligament connecting the rami, to open and close its mouth. This is accomplished by its chewing muscles, which are relatively underdeveloped. Jaw depression creates an oral opening large enough for the slender tongue to flick out. It has a length of around 60 cm (24 in) and is more triangular in the back but becomes more rounded towards the front and ends in a rounded tip. The tongue has backward-curving papillae and is extremely moist due to the large salivary glands.

The tongue can only move forwards and backwards, due the tiny mouth and shape of the snout. During feeding, the animal relies on the direction of its head for aim. When fully extended, the tongue reaches 45 cm (18 in), and can move in and out around 160 times per minute (nearly three times per second). A unique sternoglossus muscle, a combination of the sternohyoid and the hyoglossus, anchors the tongue directly to the sternum. The hyoid apparatus is large, V-shaped and flexible and supports the tongue as it goes in and out of the mouth. The buccinators loosen and tighten as the tongue goes in and out, preventing food from falling out. When retracted, the tongue is held in the oropharynx, preventing it from blocking respiration.

The anteater rubs its tongue against its palate to smash the insects for swallowing. Unlike other mammals, giant anteaters swallow almost constantly when feeding. The giant anteater's stomach, similar to a bird's gizzard, has hardened folds to crush food, assisted by some sand and soil that was consumed. The giant anteater cannot produce stomach acid of its own, but digests using the formic acid of its prey.

The giant anteater is native to Central and South America; its known range stretches from Honduras to Bolivia and northern Argentina, and fossil remains have been found as far north as northwestern Sonora, Mexico. It is largely absent from the Andes and has been fully extirpated in Uruguay, Belize, El Salvador, and Guatemala, as well as in parts of Costa Rica, Brazil, Argentina, and Paraguay. The species can live in both tropical rainforests and arid shrublands, provided enough prey is present to sustain it.

The species is listed as vulnerable by the International Union for Conservation of Nature, due to the number of regional extirpations, and under Appendix II by CITES, tightly restricting international trade in specimens. By 2014, the total population declined more than 30 percent "over the last three generations". In 1994, some 340 giant anteaters died due to wildfires at Emas National Park in Brazil. The animal is particularly vulnerable to fires as its coat can easily catch ablaze and it is too slow to escape.

Human-induced threats include collision with vehicles, attacks by dogs, and destruction of habitat. One study of anteater mortality along roads found that they are likely to be struck on linear roads near native plants. A 2018 study in Brazil found that: (1) roads were more likely to be detrimental to anteaters through habitat fragmentation than vehicle accidents, (2) 18–20% of satisfactory anteater habitat did not reach minimum patch size (3) 0.1–1% of its range was had dangerously high road density, (4) 32–36% of the anteater's distribution represented critical areas for its survival and (5) more conservation opportunities existed in the north of the country. A 2020 study in the Brazilian Cerrado found that road mortality can cut population growth by 50 percent at the local level.

The giant anteater is commonly hunted in Bolivia, both as a trophy and food. The animal's thick, leathery hide is used to make horse-riding equipment in the Chaco. In Venezuela, it is slain for its claws. Giant anteaters are also killed for their perceived danger, particularly during threat displays. The biggest ecological strengths of the species is its wide range and adaptability. The Amazon, Pantanal and the Cerrado have various protected areas were the anteater finds refuge. In Argentina, some local governments list it as national heritage species, affording it official protection.

Despite its iconic status, the giant anteater is little studied in the wild and research has taken place in a small number of areas. The species may use multiple habitats. A 2007 study of giant anteaters in the Brazilian Pantanal found the animals move and forage in open areas and rest in forest; the latter provide shade when the temperature rises and retain heat when the temperature drops. Anteater may travel an average of 3,700 m (12,100 ft) per day. Giant anteaters can be either diurnal or nocturnal. A 2006 study in the Pantanal found those anteaters to be mostly nocturnal when it is warm, but became more active in daylight hours as the temperature dropped. Diurnal giant anteaters have been observed at Serra da Canastra. Nocturnality in anteaters may be a response to human disturbances.

Giant anteaters prefer dense brush to sleep in, but when it gets cooler, they may use tall grass. When they need to rest, they carve a shallow cavity in the ground. The animal sleeps curled up with its bushy tail over its body; both to keep it warm and camouflage it from predators. One anteater was recorded sleeping flat on its side with the tail unfolded on a 17 °C (63 °F) morning; possibly it was positioned this way to allow its body to absorb the sun's rays for warmth. Giant anteaters sometimes enter water; to bathe. and even swim across wide rivers. They are also able to climb and have been recorded ascending both termite mounds and trees while foraging. One individual was observed attempting to climb a tree by rearing up and grabbing onto a branch above it.