Animal Info - Seychelles Sheath-tailed Bat

Coleura seychellensis

Status: Critically Endangered

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Weight, Habitat, Birth Season, Diet, Social Organization)
5. References

Profile

Pictures: Seychelles Sheath-tailed Bat #1 (38 Kb JPEG) (Helen Burgess/Arkive); Seychelles Sheath-tailed Bat #2 (51 Kb JPEG) (Helen Burgess/Arkive); Related species - African Sheath-tailed Bat (Coleura afra) (14 Kb JPEG) (Univ. Alaska Fairbanks)

The weight of Seychelles sheath-tailed bats averages about 10 - 11 g (0.4 oz). Bats in this genus generally roost in caves and houses, in crevices and cracks. In the 1860's, 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. Its colonies are apparently divided into harem groups.

The Seychelles sheath-tailed bat occurs in the central granitic islands of the Seychelles Islands north of Madagascar. It probably was abundant throughout the Seychelles in the past, but it has declined drastically and is now extinct on most islands. The reasons for its decline are unknown. It has been suggested that the barn owl, Tyto alba, introduced in 1949, may be responsible.

Tidbits

*** The Seychelles sheath-tailed bat is one of the world's rarest mammals.

*** Bats in the genus Coleura usually do not roost upside down; instead, they crawl into a cranny or press their undersides flat against stone walls (Nowak & Paradiso 1983).

*** The name "sheath-tailed" refers to the juxtaposition of the tail and the membrane that stretches between the hind legs, whereby the last half of the tail protrudes free from the membrane. By adjustment of the hind legs in flight, the membrane can be lengthened or shortened as it slips over the tail, giving these bats precise maneuverability in flight. They utilize acrobatic flight as they fly within the understory of the rain forest hunting both airborne and foliage-clinging insects. (Bonaccorso 1998)

Status and Trends

IUCN Status:

1988 - 1994: Endangered
1996 - 2003: Critically Endangered (Criteria: B1+2cde, C2b, D) (Population Trend: Decreasing) (IUCN 2003a)
2004: Critically Endangered (Criteria: CR C2a(i,ii)) (Population Trend: Decreasing) (IUCN 2004)

Countries Where the Seychelles Sheath-tailed Bat Is Currently Found:

2004: Occurs in Seychelles (IUCN 2004).

Population Estimates:

[Note: Figures given are for wild populations only.]

WORLD (Seychelles)
- 1999: Fewer than 50 individuals (IUCN cited in Nowak 1999)
- 2004: 50 - 100 individuals (IUCN 2004)

History of Distribution:

The Seychelles sheath-tailed bat occurs in the central granitic islands of the Seychelles Islands north of Madagascar. It probably was abundant throughout the Seychelles in the past, but it has declined drastically and is now extinct on most islands.

Threats and Reasons for Decline:

The reasons for its decline are unknown. It has been suggested that the barn owl, Tyto alba, introduced in 1949, may be responsible (Cheke & Dahl 1981).

Data on Biology and Ecology

Weight:

The weight of Seychelles sheath-tailed bats averages about 11 g (0.4 oz) in parous females and 10 g (0.36 oz) in adult males.

Habitat:

Bats in the genus Coleura generally roost in caves and houses, in crevices and cracks. In the 1860's, 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 (Cheke & Dahl 1981).

The Seychelles sheath-tailed bat is one of the species that live in both the Madagascar & Indian Ocean Islands Biodiversity Hotspot (Cons. Intl. 2005) and the Seychelles & Mascarene Islands Forests Global 200 Ecoregion. (Olson & Dinerstein 1998, Olson & Dinerstein 1999)

Birth Season:

Births occur during the November - December rainy season.

Diet:

The Seychelles sheath-tailed bat is insectivorous.

Social Organization:

Colonies of the Seychelles sheath-tailed bat are apparently divided into harem groups.

References

Arkive, Bat Cons. Intl., Bonaccorso 1998, Burton & Pearson 1987, Cheke & Dahl 1981, Cons. Intl. 2005, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Nowak 1999, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999

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Last modified: November 2, 2005;