The Origin of the Fauna of the Greater Antilles, with Discussion of Dispersal of Animals Over Water and Through the Air

Abstract

The region from which most of the fauna of the Greater Antilles appear to have been derived is Central America, and many have favored the view that there was once a land bridge between these two regions over which the animals migrated. But this paper holds that such an hypothesis is unsatisfactory on several counts. Both geological and zoogeographical evidence for it are poor. An alternative hypothesis is suggested that the organisms crossed a water gap, perhaps from Honduras to Jamaica. The chances of dispersal of organisms across water gaps are discussed, partly mathematically, with the conclusion that such dispersals appear reasonably orderly. Wind storms play an important part in such dispersals. The fauna of the Greater Antilles is moderately homogeneous but it is very orderly; the latter appears due to the fact that the animals are still distributed along the migration routes. The fauna also is irregularly depauperate and shows various characteristics of an oceanic fauna.