Seychelles sheath-tailed bat Coleura seychellensis

The Seychelles sheath-tailed bat is a Critically Endangered species known only from the islands of Mahe, Silhouette, Praslin and La Digue.  In the 1800s it was described as being common on Mahe but declined throughout the 1900s.  Today the known roost sites on Praslin and La Digue have all been abandoned.  The only  signficant roosts are on Silhouette island where two caves have been located.  These caves are part of a single system of passages in a boulder field.  Three small roosts on Mahe have been located.

The Seychelles sheath-tailed bat is classified as Critically Endangered by IUCN, is the 25th EDGE (Evolutionarily Distinct and Globally Endangered) species lised by the Zoological Society of London.  It is a trigger species for the Alliance For Zero Extiction highlighting the importance of Silhouette island for the conservation of the species.

The Silhouette roosts have been monitored by the Nature Protection Trust of Seychelles since 1997 and a study of the roost in 2003 recorded 32 bats.  This low figure is an indication of the precarious status of this bat.

NPTS has installed an infra-red CCTV system into one roost so that monitoring can continue without disturbance to one of the world's rarest and least-known mammals. This is revealing important new information on the behaviour and ecology of this threatened species.

Habitat restoration around the roosts and the feeding areas resulted in increases in beetle populations (favoured by the bats during the breeding season) and consequently a highly successful breeding season in 2007-8. After 3 years of decline the popualtion recovered to the maximum of 32 by April 2008. 2008 proved to be a good year for the bats, with a new record of 37 bats set in December. At this time at least one bat was occasionally returning to an abandoned roost. It seems that the Silhouette population is finally starting to recover. It is hoped that the same success can be repeated on Mahe where 30-50 bats survive in three isolated roosts, all threatened by development. Conservation management work is planned for this population as well.

Since 2009 NPTS has been working with the Seychelles Ministry of Environment to conserve the Mahe populations of sheath-tailed bats.

Recent publications on the Seychelles sheath-tailed bat (reprints available here):

• Matyot, P. 1995  The sheath-tailed bat Coleura seychellensis Peters, 1868 (Chiroptera: Emballoneuridae) rediscovered on Silhouette island.   Phelsuma 4; 67-69
• Rocamora, G. & F. Joubert 2004  Coleura seychellensis: monitoring.   Phelsuma 12
• Joubert, F.  2004  Investigation into the ecology of the Seychelles sheath-tailed bat.   Phelsuma 12
• Burgess, H. & N. Lee 2004  A behavioural study of the Silhouette sheath-tailed bat.   Phelsuma 12
• Gerlach, J.  2004 The bats of Silhouette island, Seychelles.  Phelsuma 12
• Gerlach, J.  2005  Invertebrates associated with the Seychelles sheath-tailed bat Coleura seychellensis.  Phelsuma 13
• Gerlach J & Taylor, M. 2006 Habitat as a critical factor in the decline of the Seychelles Sheath-Tailed Bat Coleura seychellensis. Acta Chiopt.. 8; 129-139.
• Gerlach, J. 2007 (in press) Vocalizations of the Seychelles sheath-tailed bat Coleura seychellensis. Le Rhinolophe
• Gerlach, J. 2008 Status and conservation of the Seychelles sheath-tailed bat Coleura seychellensis on Silhouette island, Seychelles. Endangered Species Research.