Kitti's hog-nosed bat (Craseonycteris thonglongyai) of Thailand and Burma is the smallest living mammal. Kitti's hog-nosed bat also known as the bumblebee bat is a vulnerable species of bat.
It is about 29 to 33 mm (1.1 to 1.3 in) in length and weighs only about 1.5 to 2 g.
It has a reddish-brown or grey coat, and a distinguishing flat and pig-like nose. While the ears of Kitti's hog-nosed bat are relatively large, its eyes are small. The wings of this mammal are relatively large too, that allow the bat to hover.
It feeds on small flies and spiders.
Read more at: http://en.wikipedia.org/wiki/Kitti's_hog-nosed_bat