text: kitti 's hog - nosed bat kitti 's hog - nosed bat ( ) , also known as the bumblebee bat , is a vulnerable species of bat and the only extant member of the family . 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 arguably the world 's smallest mammal . 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 to 33 mm ( 1 . 1 to 1 . 3 in ) in length and 2 g ( 0 . 071 oz ) in 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 at 1 . 2 to 2 . 7 g ( 0 . 042 to 0 . 095 oz ) but is longer , measuring 36 to 53 mm ( 1 . 4 to 2 . 1 in ) from its head to the base of the tail . 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 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 the hills in sai yok district , province , within the drainage basin of the noi river . while the sai yok national park in the hills 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 of the and karen hills outside the , , and rivers of 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 . behaviour kitti 's hog - nosed bat roosts in the caves of limestone hills , far from the entrance . while many caves contain only 10 to 15 individuals , the average group size is 100 , with a maximum of about 500 . individuals roost high on walls or roof domes , far apart from each other . bats also undertake seasonal migration between caves . kitti 's hog - nosed bat has a brief activity period , leaving its roost for only 30 minutes in the evening and 20 minutes at dawn . these short flights are easily interrupted by heavy rain or cold temperatures . during this period , the bat forages within fields of cassava and kapok or around the tops of bamboo clumps and teak trees , within one kilometre of the roosting site . the wings seem to be shaped for hovering flight , and the gut contents of specimens include spiders and insects that are presumably gleaned off foliage . nevertheless , most prey is probably caught in flight . main staples of the bat 's diet include small flies ( , , and ) , hymenopterans , and . late in the dry season ( around april ) of each year , females give birth to a single offspring . during feeding periods , the young either stays in the roost or remains attached to the mother at one of her two vestigial pubic nipples . taxonomy kitti 's hog - nosed bat is the only extant species in the family , which is grouped in the superfamily as a result of molecular testing . based on this determination , the bat 's closest relatives are members of the families and . kitti 's hog - nosed bat was unknown to the world at large prior to 1974 . its common name refers to its discoverer , thai zoologist kitti thonglongya . thonglongya worked with a british partner , john e. hill , in classifying bats of thailand ; after thonglongya died suddenly in february 1974 , hill formally described the species , giving it the binomial name in honour of his colleague . conservation as of the species ' most recent review in 2008 , kitti 's hog - nosed bat is listed by the iucn as vulnerable , with a downward population trend . soon after the bat 's discovery in the 1970s , some roosting sites became disturbed as a result of tourism , scientific collection , and even the collection and sale of individuals as souvenirs . however , these pressures may not have had a significant effect on the species as a whole , since many small colonies exist in hard - to - access locations , and only a few major caves were disturbed . another potential risk is the activity of local monks , who have occupied roost caves during periods of meditation . currently , the most significant and long - term threat to the thai population could be the annual burning of forest areas , which is most prevalent during the bat 's breeding season . in addition , the proposed construction of a pipeline from burma to thailand may have a negative impact . threats to the burmese population are not well known . in 2007 , kitti 's hog - nosed bat was identified by the evolutionarily distinct and globally endangered project as one of its top 10 " focal species " .