The Seychelles sheath-tailed bat (Coleura seychellensis) is a sac-winged bat found in the central granitic islands of the Seychelles. They are nocturnal insectivores that roost communally in caves. The species was previously abundant across much of the archipelago, but has since seen a substantial loss of habitat. The International Union for Conservation of Nature has listed the species as being critically endangered, due to population decline. This is mainly due to an increase in land development and the introduction of invasive species. Ecology The weight of Seychelles sheath-tailed bats averages about . Bats in this genus generally roost in caves and houses, in crevices and cracks. In the 1860s, the Seychelles sheath-tailed bat was reported to fly around clumps of bamboo towards twilight, and in the daytime to be found roosting in the clefts of the mountainside facing the sea and with a more or less northern aspect. These hiding places were generally covered over with the large fronds of endemic palms. The Seychelles sheath-tailed bat is insectivorous. It feeds predominantly on marsh-associated Ceratopogonidae, in contrast to Curlionidae in palm woodland. Its colonies are apparently divided into harem groups. It has been the focus of recent intensive research, which has determined that it is a species associated with small clearings in forests where it feeds on a wide variety of insect species. Observations of coastal or marsh feeding are thought to be bats that have been forced into feeding in unusual situations due to habitat deterioration. Although the species is not a specialist and has a high reproductive potential, it is very vulnerable to disturbance and requires several roost sites within healthy habitat. Status It was probably abundant throughout the Seychelles in the past, but it has declined drastically and is now extinct on most islands. The International Union for Conservation of Nature lists this bat as being critically endangered. In 2013, Bat Conservation International listed this species as one of the 35 species of its worldwide priority list of conservation. It is one of the most endangered animals, fewer than 100 are believed to exist in the world. The Seychelles sheath-tailed bat has suffered from habitat deterioration due to the effects of cultivation of coconut plantations and the introduction of the kudzu vine, both of which have reduced the incidence of scrub and the availability of insect prey. The largest surviving roost is on Silhouette Island, although small roosts