Five extant species within one extant genus are widely recognized. Four are in Central and South America whilst the fifth is in Asia.
General Appearance Edit
Size varies between types, but most tapirs are about 2 m (6.6 ft) long, stand about 1 m (3 ft) high at the shoulder, and weigh between 150 and 300 kg (330 and 700 lb). Their coats are short and range in color from reddish-brown, to grey, to nearly black, with the notable exceptions of the Malayan tapir, which has a white, saddle-shaped marking on its back, and the mountain tapir, which has longer, woolly fur. All tapirs have oval, white-tipped ears, rounded, protruding rumps with stubby tails, and splayed, hooved toes, with four toes on the front feet and three on the hind feet, which help them to walk on muddy and soft ground. Baby tapirs of all types have striped-and-spotted coats for camouflage. Females have a single pair of mammary glands, and males have long penises relative to their body size.
Physical Characteristics Edit
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. Tapirs often exhibit the flehmen response, a posture in which they raise their snouts and show their teeth to detect scents. This response is frequently exhibited by bulls sniffing for signs of other males or females in oestrus in the area. The length of the proboscis varies among species; Malayan tapirs have the longest snouts and Brazilian tapirs have the shortest. 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.
Totaling 42 to 44 teeth, this dentition is closer to that of equids, which may differ by one less canine, than their other perissodactyl relatives, rhinoceroses. Their incisors are chisel-shaped, with the third large, conical upper incisor separated by a short gap from the considerably smaller canine. A much longer gap is found between the canines and premolars, the first of which may be absent. Tapirs are lophodonts, and their cheek teeth have distinct lophs (ridges) between protocones, paracones, metacones and hypocones.
Tapirs have brown eyes, often with a bluish cast to them, which has been identified as corneal cloudiness, a condition most commonly found in Malayan tapirs. The exact etiology is unknown, but the cloudiness may be caused by excessive exposure to light or by trauma. However, the tapir's sensitive ears and strong sense of smell help to compensate for deficiencies in vision. Tapirs have simple stomachs and are hindgut fermenters that ferment digested food in a large cecum.
Young tapirs reach sexual maturity between three and five years of age, with females maturing earlier than males. 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. The natural lifespan of a tapir is about 25 to 30 years, both in the wild and in zoos. Apart from mothers and their young offspring, tapirs lead almost exclusively solitary lives.
Although they frequently live in dryland forests, tapirs with access to rivers spend a good deal of time in and underwater, 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 under water to allow small fish to pick parasites off their bulky bodies. Along with freshwater lounging, tapirs often wallow in mud pits, which also help to keep them cool and free of insects.
In the wild, the tapir's diet consists of fruit, berries, and leaves, particularly young, tender growth. Tapirs will spend many of their waking hours foraging along well-worn trails, snouts to the ground in search of food. Baird's tapirs have been observed to eat around 40 kg (85 lb) of vegetation in one day.
Tapirs are largely nocturnal and crepuscular, although the smaller mountain tapir of the Andes is generally more active during the day than its congeners. They have monocular vision. Copulation may occur in or out of water, and in captivity, mating pairs will often copulate multiple times during oestrus. Intromission lasts between 10 and 20 minutes.
Habitat, Predation, and Vulnerability Edit
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. Hunting for meat and hides has substantially reduced their numbers and, more recently, habitat loss has resulted in the conservation watch-listing of all four species: both the Brazilian tapir and the Malayan tapir are classified as vulnerable; and the Baird's tapir and the mountain tapir are endangered.
Evolution and Natural History Edit
The first tapirids, such as Heptodon, appeared in the early Eocene of North America. They appeared very similar to modern forms, but were about half the size, and lacked the proboscis. The first true tapirs appeared in the Oligocene. By the Miocene, such genera as Miotapirus were almost indistinguishable from the extant species. Asian and American tapirs were believed to have diverged around 20 to 30 million years ago; tapirs later migrated from North America to South America around 3 million years ago, as part of the Great American Interchange. For much of their history, tapirs were spread across the Northern Hemisphere, where they became extinct as recently as 10,000 years ago. T. merriami, T. veroensis, T. copei, and T. californicus became extinct during the Pleistocene in North America. The giant tapir Megatapirus survived until about 4,000 years ago in China.
Approximate divergence times based on a 2013 analysis of mtDNA sequences are 0.5 Ma for T. kabomani and the T. terrestris–T. pinchaque clade, 5 Ma for T. bairdii and the three South American tapirs and 9 Ma for the T. indicus branching. T. pinchaque arises from within a paraphyletic complex of T. terrestris populations.