Bumblebee Bat

Kitti's Hog-nosed Bat (Craseonycteris thonglongyai), also known as the bumblebee bat, is a vulnerable species of bat and the only member of the family Craseonycteridae. It occurs in western Thailand and southeast Burma, where it occupies limestone caves along rivers.

Kitti's Hog-nosed Bat is the smallest species of bat and one of the world's smallest mammals. It has a reddish-brown or grey coat, with a distinctive pig-like snout. Colonies range greatly in size, with an average of 100 individuals per cave. The bat feeds during short activity periods in the evening and dawn, foraging around nearby forest areas for insects. Females give birth annually to a single offspring.

Although the bat's status in Burma is not well-known, the Thai population is restricted to a single province and may be at risk for extinction. Its potential threats are primarily anthropogenic, and include habitat degradation and the disturbance of roosting sites.

Description

Kitti's Hog-nosed Bat is about 29–33 millimetres (1.14–1.30 in) in length and 2 grams (0.07 oz) in mass), hence the common name of "bumblebee bat". It is the smallest species of bat and may be the world's smallest mammal, depending on how size is defined. The main competitors for the title are small shrews; in particular, the Etruscan shrew may be lighter (1.2–2.7 g) (0.042-0.095 oz) but is longer (36–53 mm head-and-body) (1.42-2.09 in).

The bat has a distinctive swollen, pig-like snout with thin, vertical nostrils. Its ears are relatively large, while its eyes are small and mostly concealed by fur. Its teeth are typical of an insectivorous bat. The dental formula is 1:1:1:3 in the upper jaw and 2:1:2:3 in the lower jaw, with large upper incisors.

The bat's upperparts are reddish-brown or grey, while the underside is generally paler. The wings are relatively large and darker in colour, with long tips that allow the bat to hover. Despite having two caudal vertebrae, Kitti's Hog-nosed Bat has no visible tail. There is a large web of skin between the hind legs (the uropatagium) which may assist in flying and catching insects, although there are no tail bones or calcars to help control it in flight.

Range and distribution

Kitti's Hog-nosed Bat occupies the limestone caves along rivers, within dry evergreen or deciduous forests. In Thailand, Kitti's Hog-nosed Bat is restricted to a small region of Kanchanaburi Province, within the drainage basin of the Khwae Noi River. While the Sai Yok National Park contains much of the bat's range, some Thai populations occur outside the park and are therefore unprotected.

Since the 2001 discovery of a single individual in Burma, at least nine separate sites have been identified in the limestone outcrops outside the Thanlwin, Ataran, and Gyaing Rivers of Kayin and Mon States. The Thai and Burmese populations are morphologically identical, but their echolocation calls are distinct. It is not known whether the two populations are reproductively isolated.

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