Lesser Naked Bat

The Lesser Naked Bat is a striking, nearly hairless molossid bat native to Sulawesi and parts of the Philippines. It is one of only two species in the genus Cheiromeles, both remarkable for their almost complete lack of fur, giving them a wrinkled, leathery appearance. This species is smaller than its close relative, the Naked Bulldog Bat (C. torquatus), and roosts colonially in caves and hollow trees. It is a specialized insectivore that plays an important role in controlling nocturnal insect populations.

Sulawesi (Indonesia) and the Philippines

Endemic to the island of Sulawesi in Indonesia, with records also from parts of the Philippines. Its range is patchy and tied closely to the availability of cave and hollow-tree roosts.

Altitude and depth

Typically found from sea level up to around 1000 meters elevation, favoring lowland to mid-elevation forested areas.

Seasonal movements

No long-distance migration is known; the species shows relatively stable year-round activity, though breeding may be linked to seasonal insect abundance patterns.

Found in lowland and hill tropical rainforests, often near caves, rock crevices, and hollow trees that serve as roosting sites. It can also be found in disturbed or secondary forest areas as long as suitable roosting structures remain.

Adaptations to its environment

Its near-total lack of fur is thought to reduce parasite load and aid thermoregulation in the humid tropical climate. It has powerful, muscular limbs and unique pouches on its body used to store folded wings while crawling, an adaptation for its unusual quadrupedal locomotion on the ground and cave surfaces.

Listed as Least Concern by the IUCN due to a relatively wide distribution and presumed stable population, although data on population trends remain limited.

Estimated population

No precise global population estimate exists; the population is presumed stable but likely under-monitored due to the species' cryptic cave-roosting habits.

Main threats include deforestation, cave disturbance from guano mining and tourism, and habitat degradation from agricultural expansion in Sulawesi and the Philippines.

Diseases and parasites

Like other bats, it may host various ectoparasites such as bat flies and mites, as well as being a potential reservoir for certain viruses, though specific studies on this species are limited.

Some populations occur within protected areas and national parks in Sulawesi, but targeted conservation programs specifically for this species are limited. General cave and forest protection laws in Indonesia and the Philippines provide indirect benefits.

Recommended actions

Recommended actions include better population surveys, protection of key cave roosts from disturbance, and inclusion of the species in regional bat conservation and habitat management plans.

The body is almost entirely devoid of fur, appearing dark grayish-brown to blackish and wrinkled, resembling bare skin more than typical bat fur coverage. It has a robust, thickset body, large ears, and a distinctive throat pouch region.

Size

Body length approximately 8-9 cm, with a wingspan estimated around 30-35 cm, smaller than the related Cheiromeles torquatus.

Weight

Adults typically weigh between 60-80 grams, lighter than the larger naked bulldog bat.

Distinctive features

Distinguished from Cheiromeles torquatus mainly by its smaller overall size and subtle skull and dental differences; both species share the unusual hairless, wrinkled skin unique among bats.

Differences between males and females

Sexual dimorphism is minimal, with males and females showing similar size and coloration, though males may be marginally larger.

Highly colonial, roosting in large groups within caves or hollow trees, sometimes numbering in the hundreds to thousands of individuals.

When it is active

Strictly nocturnal, emerging at dusk to forage for flying insects and returning to communal roosts before dawn.

Diet

Insectivorous, feeding primarily on flying insects such as moths, beetles, and other night-flying arthropods captured in flight.

How it feeds and hunts

Uses echolocation to detect and capture insect prey in open airspace above forest canopy and near cave entrances, employing fast, agile flight typical of molossid bats.

Communication

Communicates through high-frequency echolocation calls for navigation and prey detection, along with social vocalizations within roosting colonies.

Interactions with other species

Preyed upon occasionally by snakes, birds of prey, and other cave-dwelling predators; may share roosting caves with other bat species and contribute to guano-based cave ecosystems.

Role in its ecosystem

Plays an important ecological role as an insectivorous predator, helping regulate populations of nocturnal flying insects in tropical forest ecosystems.

Breeding biology is not fully documented but is presumed to follow typical molossid patterns with a single offspring per breeding cycle and a gestation period of a few months.

Raising the young

Females likely give birth to a single pup which is nursed and cared for in the maternity roost until capable of independent flight, similar to related bat species.

Maturity and lifespan

Specific data are lacking, but related molossid bats typically reach sexual maturity within one year and can live up to 10 years or more in the wild.

Classification

Class Mammalia > Order Chiroptera > Family Molossidae > Genus Cheiromeles > Species Cheiromeles parvidens

Scientific synonyms

Sometimes historically considered conspecific with or closely allied to Cheiromeles torquatus before being recognized as a distinct species based on smaller size and morphological differences.

Recent studies

Recent taxonomic and morphological studies have helped clarify the distinction between Cheiromeles parvidens and Cheiromeles torquatus, confirming their status as separate species.

Compared with similar species

Compared to Cheiromeles torquatus, the Lesser Naked Bat is smaller in body size and wingspan, though both share the rare hairless trait among bats and similar ecological niches.

This bat is one of only two naked (hairless) bat species in the world. It has skin pouches on its sides where it tucks its folded wings while crawling on all fours like a small mammal. Its bare, wrinkled skin gives it an almost alien appearance among bats.

Where and how to see it

Best observed at dusk near cave entrances in Sulawesi's forested regions, particularly around known bat cave systems; patience and knowledge of local cave roosts greatly increase chances of sighting.

Risks to humans

No notable risk to humans; however, as with all bats, caution should be taken to avoid direct contact due to potential zoonotic disease transmission.

Human uses

Not commonly used by humans, though in some areas guano from bat caves, including those hosting this species, may be collected as fertilizer.