50 - 100 individuals (2004). 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.