Kitti's hog-nosed or bumble-bee bat (Craseonycteris thonglongyai)
The Kitti's hog-nosed bat is the only living species of the family Craseonycteridae (ARKive, Wikipedia), grouped in the superfamily Rhinolophoidea due to molecular testing (Wikipedia). Its closest relatives are members of the families Hipposideridae and Rhinopomatidae (Wikipedia). The bat was discovered in 1974 by the Thai zoologist Kitti Thonglongya. John E. Hill described the species, naming it Craseonycteris thonglongyai after his colleague (Wikipedia).
The bat is about 29-33 mm long, its forearms are 22-26 cm long and it weighs 2.7-2 g (Animal Diversity Web, Wikipedia); it is about the size of a large bumblebee (ADW). It is the smallest species of bat and possibly the world's smallest mammal, although the Etruscan shrew may be lighter (Animal Diversity Web, ARKive, Wikipedia). It has long grey, reddish- or greyish-brown fur on its back and shorter, paler fur on its underparts. The relatively large wings and the large membrane between the legs, called the uropatagium, are darker. The flat, fleshy, swollen, pig-like muzzle has large, thin, vertical nostrils, separated by a wide septum and situated between very small eyes, which are mostly concealed by facial hair. The relatively large, membranous ears are 9-10.2 mm and have a well-developed tragus, about half the ear length. The tragus enhances the bat's ability to pinpoint the echoes with which it navigates (ARKive). The 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 relatively large upper incisors and long, narrow lower incisors. The small skull has a large inflated spherical braincase and lacks lambdoidal crests, postorbital processe, and supraoccipital ridges. There is a sagittal crest - a ridge of bone running down the top middle of the skull. The zygomata, the arch in the cheek, is slender but complete (ADW). The long wing tips allow the bat to hover (Wikipedia).
The bat has clawed thumbs and a slender, long, narrow hindfoot. It does not have an external tail, but has two caudal vertebrae (Wikipedia). Males have a rounded, glandular swelling on the base of the throat; this is less prominent or absent in females (ARKive). Females have 2 sets of teats, one on the chest and the other in the pubic area. The pubic teats are thought to be vestigial or not fully developed. There large web of skin between the hind legs (the uropatagium) may help it to fly and catch insects, but lacks tail bones or calcars to help control it in flight (Wikipedia).
The bat is found in the Bilauktaung mountain ranges in the west of Thailand, in a small region of the Tenassrim Hills in Sai Yoke, Kanchanaburi Province, within the drainage basin of the Khwae Noi River, but also lives in Mon State in south-east Myanmar near the border with Thailand (ADW, ARKive, Wikiepedia). Myanmar bats occur in at least nine sites in the Dawna and Karen Hills outside the Thanlwin, Ataran, and Gyaing Rivers of Kayin and Mon States. The bat lives at 0-500 m above sea level (IUCN) and is associated with limestone caves and outcrops near rivers, within dry evergreen or deciduous forests, and can survive in degraded areas (Wikipedia).
The bat seems to be wary and prefers to roost near the tops of small, limestone caves for warmth. It can be found deep inside small caves, hanging high on the walls or roof domes, suspended by its toes and strong claws (ARKive, Wikipedia). A 'tendon-locking mechanism' keeps the claws bent with very little muscular effort; hanging upside down lets the bat swiftly take flight from the resting position (ARKive). Many caves contain 10-15 individuals, but the average group size is 100 and the maximum is 500 (ARKive, Wikipedia). Individuals roost far apart from each other (Wikipedia). Bats also undertake seasonal migration between caves (Wikipedia).
The bat emerges from its cave for 30 minutes shortly after sunset for 20 minutes just before dawn, when it hunts in fields of cassava and kapok or around the tops of bamboo clumps and teak and other deciduous hardwood trees (ARKive, Wikipedia). The flights are easily interrupted by heavy rain or cold temperatures (Wikipedia). The bat commonly forages in the upper canopy of the forest (ADW), usually within an area of around 1 km from the roost site (IUCN, Wikipedia). It searches for prey around the tops of teak trees and bamboo clumps, gleans spiders and insects from foliage and seizes flies nd other small flying insects from the air (ARKive, Wikipedia). It uses echolocation to locate prey and navigate through the trees (ARKive). Its high intensity sounds have a constant frequency lasting up to 2 ms followed by a shallow downward sweep lasting 1 ms. The beginning of the call has an upward sweep. The bat has a base frequency of 35 kHz and uses two other harmonics. The second one is at 70 kHz and the third one, which is weaker, is at 105 kHz (ADW). The Thai and Myanmar Burmese populations have distinct echolocation calls (Wikipedia). The bat feeds mainly on insects, as well as some spiders, and catches its prey while flying (ADW).
The bats breed once a year in late April to May. The female gives birth to one infant in late April, the dry season (Wikipedia). During feeding periods, the young either stays in the roost or stays attached to one of the mother's two vestigial pubic nipples (Wikipedia). The infant is usually attached to the mother inside the cave, but the mother leaves it in the roost whilst she ventures out to forage (ARKive). The infant takes 1 year to reach independence. The lifespan is thought to be around 5-10 years (ADW).
The IUCN Red List considers the bat to be Vulnerable on the IUCN Red List: the U.S. Endangered species list considers it to be Endangered (ADW); the population is declining (Wikipedia). The IUCN Redlist reports that the population of 5,100 individuals in 35 caves in Thailand and over 1,500 in eight caves in Myanmar is decreasing and is disturbed by human activity in caves, including habitat-altering limestone extractions (IUCN, Wikipedia). The foraging habitats are being deforested, decreasing prey availability. The bat is affected by disturbance of roosts by religious visits, fertilizer collection and tourism (by developing 'show caves') (ARKive, Wikipedia). There is also the potential for the extraction of limestone which would cause habitat destruction.(IUCN). Shortly after the discovery of this species in the 1970s, the bat was threatened from disturbance by tourists, scientific collection, and collection for tourist souvenirs, with some caves being abandoned in Thailand (ARKive, Wikipedia), but some roost caves are inaccessible. In Myanmar, the bat may be impacted by smoke and dust emitted from cement factories near foraging areas (ARKive). Many of the caves are Buddhist sites and attract many pilgrims for meditation; some bats abandon their roosts, although the presence of monks restricts hunting of the bats (ARKive, Wikipedia), but the bats may be disturbed by the burning of incense (IUCN, Wikipedia). Burning forests near the bat caves destroys critical foraging habitat (ARKive). A proposed pipeline from Myanmar to Thailand could greatly impact this species through disturbance and habitat degradation. (ARKive, Wikipedia). Some bats occur within Sai Yok National Park (ARKive). A Conservation Action Plan was created in 2001 (ARKive). In 2007, the Evolutionarily Distinct and Globally Endangered (EDGE) project identified this species as one of its Top 10 "focal species" (Wikipedia).
Bumblebee bats (Craseonycteris thonglongyai) are found in the Oriental Region of the world. They are found in Thailand, in the Bilauktaung mountain ranges in the western part of the country; Bumblebee bats are mainly located in the Sai Yoke, Kanchanaburi Province. They can also be found in the south eastern parts of Myanmar near the border with Thailand.
Biogeographic Regions: oriental (Native )
- Humphery, S., J. Bain. 1990. Endangered Animals of Thailand. Gainsville, FL: Sandhill Crane Press.
- Pearson, D., L. Beletsky. 2008. Thailand. Northhampton, MA: Interlink Publishing Group.
Bumblebee bats are about the size of a large bumblebee, hence the common name. These bats are considered among one of the smallest mammals in the world. The size of the head and body is 29 to 33 mm long. The length of the bumblebee bat forearms are 22 to 26 m, and adults weigh between 1.7 and 2.0 g. It also has small eyes that are mostly hidden by fur. Bumblebee bats have 28 teeth, which includes relatively large incisors. The lower incisors are long and narrow. The upper body of bumblebee bats can be 2 different colors: brownish red, or gray. The underside of the bat is a paler color while the wings and the membrane between the legs, called the uropatagium, are darker.
Bumblebee bats have a few distinct characters. First, bumblebee bats do not have a tail even though they have two caudal vertebrae. Their uropatagium are rather large. Their noses are pig-like, with large nostrils separated by a wide septum. Finally they also have large ears that are 9 to 10.2 mm long. The tragus is around half the size of the ears. Females have 2 sets of nipples, one on the chest and the other in the pubic area. The nipples in the pubic area are thought to be vestigial or not fully developed. The males have a large swelling in the gland that is at the base of their throats. The wings of bumblebee bats are long and wide, making them well adapted for hovering. They have thumbs that have claws. Their hindfoot is slender, narrow, and long. Nowak (1999) descirbed bumblebee bat skulls as small with a large inflated spherical braincase and lacking lambdoidal crests, postorbital processes, and supraoccipital ridges. In both genders a sagittal crest, which is a bone that runs down the top middle of the skull, is visible. The zygomata, which is the arch in the cheek, is described as slender but complete (Nowak 1999).
Range mass: 1.7 to 2.0 g.
Range length: 29 to 33 mm.
Sexual Dimorphism: sexes alike
Other Physical Features: endothermic ; bilateral symmetry
- Nowak, R. 1999. Walker's Mammals of the World Volume 2. Baltimore, MD: The Johns Hopkins University Press.
Habitat and Ecology
Bumblebee bats preferentially use limestone caves for roosting near the tops of the caves for warmth. Bamboo forests serve for the habitat in which they find their food. Bumblebee bats commonly forage in the upper canopy of the forest.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Other Habitat Features: caves
- Hill, J., S. Smith. 1981. Craseonycteris thonglongyai. Mammalian Species, 160/1: 1-4.
Insects are bumblebee bats main source of nutrition, but they also eat some spiders. They are aerial feeders, meaning they catch their prey while flying. They prefer to fly and forage along the tops of the bamboo trees.
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore )
Due to small numbers and small stature of bumblebee bats, its ecosystem impact on its prey is probably not substantial.
Currently, nothing is known about the predators of bumblebee bats.
Life History and Behavior
Bumblebee bats use echolocation to navigate their environment. They use sounds of a high intensity and have a constant frequency lasting as long as 2 ms followed by a shallow downward sweep lasting a duration of 1 ms. The beginning of the call has an upward sweep. The bats have a base frequency of 35 kHz. They also use two other harmonics. The second one is at 70 kHz and the third one, which is weaker, is at 105 kHz. Nothing is known about how the bats communicate within their roosts.
Communication Channels: acoustic
Perception Channels: tactile ; echolocation ; chemical
- Surlykke, A., L. Miller, B. Mohl, B. Andersen, J. Christensen-Dalsgaard, M. Jergensen. 1993. Echolocation in two very small bats from Thailand: Craseonycteris thonglongyai and Myotis siligorensis. Behavioral Ecology and Sociology, 33/1: 1-12.
Bumblebee bat lifespans are unknown but it is thought to be around 5 to 10 years based on the lifespans of other closely related bats.
- Ward, A. 2004. Pocket Factfiles; Endangered Animals. Toronto, Ontario, Canada: Andromeda Oxford Limited.
Little is known about the mating systems of bumblebee bats.
Bumblebee bats have one offspring per year and breed once per year in late April to May. However, little else is known about bumblebee bat reproduction.
Breeding interval: Bumblebee bats breed once yearly.
Breeding season: Bumblebee bats breed in late April.
Average number of offspring: 1.
Average time to independence: 1 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
While inside the cave offspring are usually found attached to the mother. While the mother is foraging the offspring is left alone.
Parental Investment: female parental care ; pre-weaning/fledging (Protecting: Female)
- Hayssen, V., A. Tienhoven, A. Tienhoven, S. Asdell. 1993. Asdell's Patterns of Mammalian Reproduction: A Compendium of Species-specific Data. Ithaca, NY: Comstock Publishing Company.
- Huston, A. 2001. Microchiropteran Bats: Global Status Survey and Conservation Action Plan. Newbury, UK: The Nature Conservation Bureau Ltd..
- Kurta, A., T. Kunz. 1987. Size of bats at birth and maternal investment during pregnancy. Symposia of the Zoological Society of London, 57/1: 79-106.
- Nowak, R. 1999. Walker's Mammals of the World Volume 2. Baltimore, MD: The Johns Hopkins University Press.
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Endangered (EN)
- 1994Rare (R)
- 1990Rare (R)
- 1988Rare (R)
- 1986Insufficiently Known (K)
Bumblebee bats are considered vulnerable on the IUCN Red List and endangered on the U.S. Endangered species list. The IUCN Redlist reports that the current population of 5100 individuals is decreasing. According to the IUCN Redlist, the species is disturbed by human activity in caves. This activity includes habitat-altering limestone extractions. Their foraging habitats are also being deforested, further decreasing prey availability.
US Federal List: endangered
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: vulnerable
Date Listed: 01/23/1984
Lead Region: Foreign (Region 10)
Where Listed: Entire
Population location: Entire
Listing status: E
For most current information and documents related to the conservation status and management of Craseonycteris thonglongyai , see its USFWS Species Profile
Relevance to Humans and Ecosystems
Bumblebee bats have no known negative effects on humans.
As insectivores bumblebee bats may help with pest control, but its impact is not considered substantial due to small population sizes.
Positive Impacts: controls pest population
Kitti's hog-nosed bat
Kitti's hog-nosed bat (Craseonycteris thonglongyai), also known as the bumblebee bat, is a vulnerable species of bat and the only extant 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 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.
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 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 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 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 the Tenasserim Hills in Sai Yok District, Kanchanaburi Province, within the drainage basin of the Khwae Noi River. While the Sai Yok National Park in the Dawna 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 Dawna and Karen Hills 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.
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 (Chloropidae, Agromyzidae, and Anthomyiidae), hymenopterans, and psocopterans.
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.
Kitti's hog-nosed bat is the only extant species in the family Craseonycteridae, which is grouped in the superfamily Rhinolophoidea as a result of molecular testing. Based on this determination, the bat's closest relatives are members of the families Hipposideridae and Rhinopomatidae.
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 Craseonycteris thonglongyai in honour of his colleague.
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.
- Bates, P., Bumrungsri, S. & Francis, C. (2008). Craseonycteris thonglongyai. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 28 January 2009. Listed as Vulnerable
- Donati, Annabelle, and Pamela Johnson. "Which mammal is the smallest?." I wonder which snake is the longest: and other neat facts about animal records. Racine, Wis.: Western Pub. Co., 1993. 8. Print.
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- Meyers, P. 1997. Bat Wings and Tails, Animal Diversity Web. Retrieved on 12 April 2008.
- MJR Pereira, Maria João Ramos et al. (October 2006). "Status of the world's smallest mammal, the bumble-bee bat Craseonycteris thonglongyai, in Myanmar". Oryx 40 (4): 456–463. doi:10.1017/S0030605306001268.
- Hutson, A. M., Mickleburgh, S. P. and Racey, P. A. (Compilers). 2001. Microchiropteran Bats: Global Status Survey and Conservation Action Plan. IUCN/SSC Chiroptera Specialist Group. IUCN: Gland, Switzerland.
- J. E. Hill and Susan E. Smith (1981-12-03). "Craseonycteris thonglongyai". Mammalian Species 160: 1–4. doi:10.2307/3503984.
- Schlitter, Duane A. (February 1975). "Kitti Thonglongya, 1928-1974". Journal of Mammalogy 56 (1): 279–280.
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