Brown Tube Nosed Bat

Because bats are both nocturnal and capable of flight, they avoid predation by many predators. However owls hunt bats at night and climbing snakes may prey on roosting bats.

Anti-predator Adaptations: cryptic

Murina suilla has an average length of 3.3 to 6.0 cm with an average forearm length of 2.6 to 4.5 cm. The average weight of these bats is 3 to 5 grams. Brown tube-nosed bats have dark grayish brown fur. The underside of M. suilla is whitish and the flight membrane is brown. Polymorphism is not noted in this species. The entire family Vespertilionidae is generally known for its lack of nose ornaments and for a well developed tragus going to the base of the ear. The genus Murina is known for their tube-like nostrils.

Range mass: 3 to 5 g.

Range length: 3.3 to 6.0 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

There is no information on the lifespan of this species.

Brown tube-nosed bats are found in hilly areas of Southeast Asia. They may prefer areas near cultivated or grassy fields where they have been seen flying low, just over the tops of crops. Analysis of M. suilla echolocation calls suggest that they are well adapted to detecting insects in the highly cluttered forests of Southeast Asia. Members of the genus Murina have also been detected roosting in leaf litter, caves, and trees. They rarely found in habitats above 1000 meters.

Range elevation: 1000 (high) m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest

Other Habitat Features: agricultural ; caves

Murina suilla includes the synonymous names Murina balstoni Thomas 1908 and Murina canescens Thomas 1923. There are many common names for M. suilla including brown murine bats, and lesser tube-nosed bats.

Brown tube-nosed bats primarily navigate through the use of echolocation but also detect visual cues. Murina suilla has a broad range of calls which helps these bats navigate through dense forest environments and catch prey in flight. Brown tube-nosed bats begin their echolocation calls with a frequency of about 165 kHz and end their calls with a frequency of about 55.2 kHz. These short calls of about 2 milliseconds may have reduced the need for visual cues when hunting and may have led to a reduction in the use of eyes in this species. Modes of communication are not well-understood in Murina species. Like most mammals they probably use chemical, tactile, and auditory cues in communication.

Communication Channels: tactile ; acoustic ; chemical

Perception Channels: visual ; tactile ; acoustic ; echolocation ; chemical

Murina suilla appears to be at low risk of extinction. Habitat degradation is one of the factors which have been causing declines in populations of other bat species in the area. Oil palm plantation growth may pose a future threat to the species.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

No negative impacts have been documented, although bat species are sometimes implicated in the transmission of rabies and other diseases.

Negative Impacts: injures humans (carries human disease)

Humans benefit from M. suilla from its diet of insects. This may be important for protecting agricultural crops and reducing threats of insect borne pathogens. The full effect of brown tube-nosed bats on insect populations may be underepresented due to census bias.

Positive Impacts: controls pest population

Brown tube-nosed bats feed on insects and may play a role in keeping insect populations in check. The impact on insect numbers is difficult to determine because it may be underepresented due to biases in censusing methods. Mist nets which have been used in the past are usually avoided by these maneuverable bats. Harp traps are more efficient at catching brown tube-nosed bats. Future censusing using harp nets would better demonstrate the effect that M. suilla has on its ecosystem.

The use of echolocation and the tooth morphology of M. suilla suggests that it is insectivorous. In addition, analysis of the calls used in echolocation by M. suilla suggests that these bats are adept at detecting insects in cluttered habitats. Brown tube-nosed bats are also quite maneuverable, which would be helpful for catching insects in flight. There is little information about the specific insects that are captured.

Animal Foods: insects

Primary Diet: carnivore (Insectivore )

Murina suilla is found on the mainland and nearby islands of southeastern Asia. Its range includes the Malay Peninsula and the islands of Borneo, Sumatra, Java Nias and other smaller nearby islands. There are reports of this species from Sulawesi, the Peleng Islands, and New Guinea but they are outside of the accepted current distribution and are disputed.

Biogeographic Regions: oriental (Native )

Nothing is currently known about mating behavior of brown tube-nosed bats.

There is little information about the general breeding behavior of brown tube-nosed bats. Females appear to gather in maternity roosts. A related species round-eared tube-nosed bats was documented on the Malay Peninsula carrying 2 fetuses, so twins may occur occasionally.

Breeding interval: Breeding intervals are unknown currently.

Breeding season: Nothing known about seasonality of breeding.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (female): 12 months.

Average age at sexual or reproductive maturity (male): 12 months.

Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous

There is little information on parental investment in M. suilla. In most bat species, and presumably in M. suilla, female bats are solely responsible for rearing young. Females nurse their young until they are weaned. In most bat species weaning occurs around the time of independence, within a few months of birth.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)

With a small body and short, rounded wings, the brown tube-nosed bat has a high degree of flight control, enabling it to pass nimbly amongst the leaves and branches of the forest. It feeds on flying insects, detecting their presence with ultrasonic shouts of around 85 kHz. Listening for the returning echo of their shouts, the bat is able to distinguish an insect from its surroundings, using such detail as the movement of its tiny beating wings. As it approaches the insect the speed of its echolocation pulses quickens, to give pinpoint precision for the capture of its prey (3). During the breeding season, female brown tube-nosed bats gather into small groups called maternity roosts. Each female gives birth to a single pup that can weigh up to a quarter of her weight. Initially, the young pup clings to its mother's belly when on foraging flights, but soon learns to fly alone and capture insects itself. A year after birth the young become sexually mature and will mate (3).

Deforestation of primary forest for oil palm plantations, including within protected areas, is an issue of major concern and one that relies on both governmental and consumer action. Some large retailers have agreed, in collaboration with the WWF, to source products containing palm oil from plantations that are not on deforested land (7). Many scientific and charitable groups contribute to bat monitoring and local education programmes that can help to reduce persecution and raise awareness of the natural assets of the land (3).

Characterised by a simple nose with tube-shaped nostrils, this tiny member of the Vespertilionidae family (the evening bats) has long, fuzzy brown fur, tending to grey-brown on the sides and belly (2). The body is compact and the skin is capacious, allowing the bat to wriggle free of a predator's grip (3). Whilst all bats possess wings formed from a double membrane stretched between the elongated fingers, the evening bats also have a membrane stretched between their ankles and nearly enclosing the tail, known as the interfemoral membrane (4). This membrane is unusually furry in the brown tube-nosed bat. Whilst this species finds its insect prey using echolocation, its ears are small for its size. As the brown tube-nosed bat holds its mouth open much of the time in order to echolocate, it is easy to see its large, sharp teeth, used to crush hard-bodied insects (3).

This highly manoeuvrable bat occupies the densely vegetated understorey of lowland dipterocarp forest (6).

This species is found only on Peninsular Malaysia, Borneo, much of Indonesia (Java, Sumatra, and possibly Sulawesi), Nias Island, Peleng Island and New Guinea (2) (5).

Classified as Lower Risk – least concern (LR/lc) on the IUCN Red List 2004 (1).

The rapid increase in oil palm plantations has resulted in extensive loss of primary forest. Together, Malaysia and Indonesia export 88% of the world's palm oil, for use in products such as margarine, lipstick and detergent. Deforestation continues at a steady rate for conversion to agricultural land and building communities. Despite the contribution of many bats in the control of insect crop pests, persecution of bats is also a threat (7).

The brown tube-nosed bat (Murina suilla) is a species of vesper bat in the family Vespertilionidae. It can be found in the following countries: Brunei Darussalam, Indonesia, Malaysia, and the Philippines.