Their sense of smell is keen enough to locate a small covena bulb 5-8 cm underground before the new shoots are visible. Their habit of pawing sand against the belly with the front feet is thought to be a cleansing action. They grub for food with their snout. They are mainly vegetarian, feeding on cactus fruit, berries, tubers, bulbs, and rhizomes. They frequent water holes or, in the tropics, stay near running streams.
Peccaries are gregarious.
Each group of T. tajacu has a home range of about 0.5-8.0 sq km. The central part of the range is an exclusive territory, while the peripheral area is shared with other herds. The dorsal scent gland is rubbed against tree trunks and other objects for territorial marking and also seems to identify group members and coordinate movements. The difference was thought to be associated in part with the clumped distribution of the hard nuts and seeds favored by T. pecari. Exploitation of the feeding sites, together with defense against the predators that are drawn there, give advantages to large herd size.