| Chevrotains Temporal range: Early Miocene–Recent |
|
|---|---|
| Tragulus sp. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Suborder: | Ruminantia |
| Family: | Tragulidae Milne-Edwards, 1864 |
| Genera | |
Chevrotains, also known as mouse deer, are small ungulates that make up the family Tragulidae, the only members of the infraorder Tragulina. There are 10 living (extant) species in three genera,[1][2] but there are also several species only known from fossils.[3] The extant species are found in forests in South and Southeast Asia, with a single species in the rainforests of Central and West Africa.[4] They are solitary or live in pairs, and feed almost exclusively on plant material.[4] Depending on exact species, the Asian species weigh between 0.7 and 8.0 kilograms (1.5 and 18 lb), and the smallest species are also the smallest ungulates in the world.[4] The African chevrotain is considerably larger at 7–16 kilograms (15–35 lb).[5]
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The word 'chevrotain' itself is French, and can be translated as 'little goat'.
The single African species is consistently known as chevrotain.[1][4][6] The names chevrotain and mouse-deer have been used interchangeably among the Asian species,[4][7][8][9] though recent authorities typically have preferred chevrotain for the speces in the genus Moschiola and mouse-deer for the species in the genus Tragulus.[1] Consequently, all species with pale-spotted or -striped upperparts are known as chevrotains, and all the species without are known as mouse-deer.
The Telugu name for the Indian Spotted Chevrotain is "Jarini Pandi", which literally means "a deer and a pig". The Konkani name for it is "Barinka".
The Sinhala name meeminna roughly translates to 'mouse-like deer'. This was used in the scientific name of one of the Sri Lankan species, M. meminna.
The family was widespread and successful from the Oligocene (34 million years ago) through the Miocene (about 5 million years ago), but has remained almost unchanged over that time and remains as an example of primitive ruminant form. They have a four-chambered stomach to ferment tough plant foods, but the third chamber is poorly developed. Though most species feed exclusively on plant material, the Water Chevrotain occasionally takes insects and crabs, or scavenge meat and fish.[10] Like other ruminants, they lack upper incisors, and give birth to only a single young.
In other respects, however, they have primitive features, closer to non-ruminants such as pigs. All species in the family lack horns, but both genders have elongated canine teeth. These are especially prominent in males where they project out on either side of the lower jaw, and are used in fights.[4] Their legs are short and thin, which leave them lacking in agility, but also helps to maintain a smaller profile to aid in running through the dense foliage of their environment. Other pig-like features include the presence of four toes on each foot, the absence of facial scent glands, premolars with sharp crowns, and the form of their sexual behaviour and copulation.[11]
They are solitary or live in pairs.[4] The young are weaned at three months of age, and reach sexual maturity at between five and ten months, depending on species. Parental care is relatively limited. Although they lack the types of scent glands found in most other ruminants, they do possess a chin gland for marking each other as mates or antagonists, and, in the case of the water chevrotain, anal and preputial glands for marking territory. Their territories are relatively small, on the order of 13-24 hectares, but neighbors generally ignore each other, rather than competing aggressively.[11]
Some of the species show a remarkable affinity with water, often remaining submerged for prolonged periods to evade predators or other unwelcome intrusion. This has also lent support to the idea that whales evolved from water-loving creatures that looked like small deer.[12]
Traditionally, only four extant species were recognized in the family Tragulidae.[4] In 2004, T. nigricans and T. versicolor were split from T. napu, and T. kanchil and T. williamsoni were split from T. javanicus.[13] In 2005, M. indica and M. kathygre were split from M. meminna.[2] With these changes, there are 10 extant species:
There are 6 extinct chevrotains genera[3] including:
The Hypertragulidae were closely related to the Tragulidae.