Anteaters are mostly solitary mammals prepared to defend their 1.0- to 1.5-mi2 (2.6- to 2.9-km2) territories. Normally, they do not enter a territory of another anteater of the same gender, 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 an 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 and 36 °C (91 and 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 temperatures so they keep cool during periods of rest, and heat up during foraging.
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.