Seychelles Sheath-tailed Bat

The Seychelles Sheath-tailed Bat is a small insectivorous bat endemic to a handful of islands in the Seychelles archipelago. It is one of the rarest bats in the world, surviving in only a few tiny colonies. Once more widespread across the granitic Seychelles islands, it has undergone a dramatic historical decline. Its precarious status makes it an emblematic species for insular conservation in the Indian Ocean.

Seychelles (Silhouette, Mahé and North Island)

Endemic to the Seychelles, currently confirmed only on Silhouette Island, Mahé, and North Island; historically present on additional granitic islands where it is now extinct.

Altitude and depth

Sea level to roughly 400 m, mostly in lowland and coastal habitats near roost sites.

Seasonal movements

No long-distance migration; some seasonal variation in activity linked to insect abundance and rainfall patterns, but no true hibernation given the tropical climate.

Roosts in caves, rock crevices, and ruined buildings, typically near coastal forest and mixed woodland; hunts over forest edges, glacis (granite outcrops) and coastal vegetation.

Adaptations to its environment

Echolocation and agile flight allow effective nocturnal insect capture in cluttered forest and rocky habitats; roosting in caves and crevices provides thermal stability and protection from predators.

Critically Endangered (IUCN) due to an extremely small, fragmented population confined to very few roost sites, continuing habitat degradation, and vulnerability to stochastic events.

Estimated population

Estimated at only a few hundred individuals total, with a declining or at best stable trend across known colonies.

Habitat loss from development and invasive vegetation, roost disturbance, predation by introduced species (rats, cats), pesticide use reducing insect prey, and small population size increasing extinction risk.

Diseases and parasites

Specific pathogens are not well documented, but as with many bats, ectoparasites (mites, fleas) and potential exposure to bat-associated viruses are plausible.

Protected under Seychelles wildlife legislation; roost sites monitored by conservation organizations; habitat restoration and invasive species control programs on Silhouette and North Island.

Recommended actions

Secure and monitor all known roosts, control invasive predators and vegetation, restore native forest corridors, reduce pesticide impacts on insect prey, and consider translocation/reintroduction to former range islands.

Uniform dark brown to grayish-brown fur, membranous wings, a distinctive tail that projects partly free from the tail membrane (sheath-tailed), and relatively large eyes for a bat.

Size

Body length approximately 5-6 cm, with a wingspan around 25-28 cm.

Weight

Approximately 8-12 grams.

Distinctive features

Distinguished from related emballonurids by its restricted Seychelles endemism, specific echolocation call structure, and the characteristic sheath-tail morphology shared within genus Coleura.

Differences between males and females

Minimal sexual dimorphism; males and females are similar in size and coloration.

Roosts in small colonies, historically numbering dozens to a few hundred individuals, now often reduced to just a handful of bats per site; social cohesion within roosts appears important for thermoregulation.

When it is active

Strictly nocturnal, emerging at dusk to forage and returning to roost before dawn.

Diet

Insectivorous, feeding on small flying insects such as moths, beetles, and flies caught in flight.

How it feeds and hunts

Uses echolocation to detect and pursue flying insects in open and semi-open habitats near forest edges and clearings.

Communication

Uses echolocation calls for navigation and hunting, plus social vocalizations within roosts for contact and possibly alarm signaling.

Interactions with other species

Vulnerable to predation and disturbance by introduced rats, cats, and possibly barn owls; competes with other insectivorous bats for prey resources.

Role in its ecosystem

Acts as a natural insect population regulator within its ecosystem, contributing to pest control in forest and coastal habitats.

Believed to breed once per year with births likely timed to periods of higher insect abundance; gestation and litter details are poorly documented but likely a single pup per female, typical of emballonurids.

Raising the young

Females carry and nurse a single pup, which clings to the mother initially before being left at the roost while she forages; weaning occurs after several weeks.

Maturity and lifespan

Sexual maturity likely reached within the first year of life; lifespan in the wild is poorly known but probably several years, consistent with small emballonurid bats.

Classification

Mammalia > Chiroptera > Emballonuridae > Coleura > Coleura seychellensis

Scientific synonyms

Taphozous seychellensis (historical usage)

Recent studies

Recent surveys and genetic studies have focused on confirming remaining colony locations and assessing genetic diversity to guide conservation planning, given the species' critically small population.

Compared with similar species

Similar in general form to other sheath-tailed bats of genus Coleura found in Africa and Asia, but distinguished by its unique island endemism and much smaller, more fragmented population.

It is one of the rarest bats on Earth, surviving in only a few known roosts worldwide; its entire global range fits within a handful of small islands smaller than many cities.

Where and how to see it

Best observed at dusk near known roost sites on Silhouette Island with permission from conservation authorities; guided eco-tours focused on Seychelles biodiversity may offer supervised viewing opportunities.

Risks to humans

No notable risk to humans.