The closest extant relatives of the tapirs are the other odd-toed ungulates, which include horses, wild asses, zebras and rhinoceroses.

[15] Tapirus augustus (formerly placed in Megatapirus), native to Southeast and East Asia, substantially larger than the Malayan tapir, also became extinct at some point during the Late Pleistocene.

[citation needed] Females have a single pair of mammary glands,[19] and males have long penises relative to their body size.

[20][21][22][23][24] The proboscis of the tapir is a highly flexible organ, able to move in all directions, allowing the animals to grab foliage that would otherwise be out of reach.

[25] The evolution of tapir probosces, made up almost entirely of soft tissues rather than bony internal structures, gives the Tapiridae skull a unique form in comparison to other perissodactyls, with a larger sagittal crest, orbits positioned more rostrally, a posteriorly telescoped cranium, and a more elongated and retracted nasoincisive incisure.

[35] Under good conditions, a healthy female tapir can reproduce every two years; a single young, called a calf, is born after a gestation of about 13 months.

Although they frequently live in dryland forests, tapirs with access to rivers spend a good deal of time in and under water, feeding on soft vegetation, taking refuge from predators, and cooling off during hot periods.

Tapirs near a water source will swim, sink to the bottom, and walk along the riverbed to feed, and have been known to submerge themselves to allow small fish to pick parasites off their bulky bodies.

[40] Adult tapirs are large enough to have few natural predators, and the thick skin on the backs of their necks helps to protect them from threats such as jaguars, crocodiles, anacondas, and tigers.

The creatures are also able to run fairly quickly, considering their size and cumbersome appearance, finding shelter in the thick undergrowth of the forest or in water.

According to 2022 study published in the Neotropical Biology and Conservation, the lowland tapir in the Atlantic Forest is at risk of complete extinction as a result of anthropogenic pressures, in particular hunting, deforestation and population isolation.

[46][47] Tapirs dispersed into South America during Pleistocene as part of the Great American Biotic Interchange with their oldest records on the continent dating to around 2.6-1 million years ago.

Habitat loss has isolated already small populations of wild tapirs, putting each group in greater danger of dying out completely.

[50] Hybrids of Baird's and the South American tapirs were bred at the San Francisco Zoo around 1969 and later produced a backcross second generation.

The Tapir Specialist Group, a unit of the IUCN Species Survival Commission, strives to conserve biological diversity by stimulating, developing, and conducting practical programs to study, save, restore, and manage the four species of tapir and their remaining habitats in Central and South America and Southeast Asia.

It involves placing radio collars on tapirs in Costa Rica's Corcovado National Park to study their social systems and habitat preferences.

[54] In 2006, Carlos Manuel Rodriguez Echandi (who was then the Costa Rican Environmental Minister) became lost in the Corcovado National Park and was found by a search party with a "nasty bite" from a wild tapir.

[56] However, such examples are rare; for the most part, tapirs are likely to avoid confrontation in favour of running from predators, hiding, or, if possible, submerging themselves in nearby water until a threat is gone.