Tapirus indicus, the Asian or Malayan tapir, is the largest of the four living species of tapirs, weighing around 350 to 400 kg (800 to 900 lbs). Its coloration is unusual, with a broad white ‘saddle’ on an otherwise black coat. This pattern creates a disruptive camouflage that helps break up the tapir's outline, making it more difficult to see in the forested areas in which it lives. The Asian tapir is a remnant of a much more diverse assemblage of tapirs that once ranged across much of Europe and Asia. This group included the giant Tapirus augustus from the Pliocene of southern China, a close relative of Tapirus indicus that was the size of a small rhinoceros. Unfortunately, the future survival of the Asian tapir is questionable – largely because of loss of habitat resulting from human population growth. It is listed as ‘endangered’ by the IUCN Red List of Threatened Species.

The Asian tapir lives in the forests and jungles of Southeast Asia, and is the only living tapir species inhabiting the Old World (see map). The other three species live in Central and South America, and are more closely related to one another than they are to the Asian tapir. Based on fossil evidence, it appears that the lineages leading to the New World tapirs and the lineage leading to the Asian tapir may have split from one another in the early Miocene. Molecular clock evidence places the divergence at about 18 to 23 million years ago (Norman and Ashley, 2000).

The skull of the Asian tapir is larger than those of the other living species, and shows modifications associated with this large size. In particular the frontal sinuses are extremely large. These air-filled cavities help maintain the skull’s external shape, while reducing its weight. The frontal sinuses of the Asian tapir are notably larger than those of the New World tapirs, as illustrated by the CT slices shown at the left. Animated visualizations of the frontal sinus cavity and cranial cavity of the Asian tapir can be found on the ‘additional imagery’ page.

Click on the thumbnail to the left for an animation (1.2 mb) of the cranial endocast of Tapirus indicus. The cranial endocast is the cavity in the skull that houses the brain and its associated blood vessels and membranes. As in most mammals, the cranial endocast conforms fairly closely to the actual shape of the brain. The two bulbous structures at the left (front) end of the endocast are casts of the ethmoidal fossa, which house the olfactory bulbs. They are unusually widely spaced compared to other mammals.

Click on the thumbnail to the left for an animation (1.3 mb) of the endocast of the cranial cavity and frontal sinus endocast of Tapirus indicus. The frontal sinus of the Asian tapir is quite large, extending over the dorsal surface of the brain.

Click on the thumbnail to the left for an animation (1.2 mb) of the cranial endocast (highlighted in red) within a semi-transparent skull of Tapirus indicus. Note that the brain does not occupy much of the volume of the skull. Nobody has accused tapirs of being mental giants.

Click on the thumbnail to the left for an animation (1.2 mb) of the endocast of the cranial cavity and sinuses (highlighted in red) of Tapirus indicus. The air-filled frontal sinus occupies a large volume in the antero-dorsal part of the non-facial portion of the skull, reducing the overall weight of the skull.