PLEISTOCENE ECOLOGY AND BIOGEOGRAPHY 411 



Carib Indians ever maintained permanent settlement on the island; 

 Rabb and Hayden note that it is uninhabited at present. This fea- 

 ture may be crucial. We can attribute the remarkable survival of 

 Capromys both on the Plana Keys and on the Little Swan Islands 

 to lack of permanent prehistoric habitation. For the archaeologist 

 this carries the corollary that the other Bahaman Islands were more 

 intensively occupied. 



The foregoing account emphasizes the mammalian fossil record. 

 In addition, there were "giant" late Pleistocene lizards (Hecht, 1951, 

 1952) turtles (Williams, 1950, 1952a), and birds (Wetmore, 1937). 

 The record of the tortoises, Testudo, is an important adjunct to the 

 extinction of the large mammals. An interesting sidelight is their 

 apparent extinction in the Greater Antilles before the main period 

 of mammalian extinction (Williams, 1952a, p. 554). Elsewhere they 

 evolved through the Tertiary and into the late Pleistocene. Species of 

 relatively small size survive in northern South America. The New 

 World giant tortoises remain only on the Galapagos. As in the case of 

 Geocapromys on the Plana Keys, there is reason to believe that these 

 islands escaped permanent occupation in prehistoric times. Heyer- 

 dahl and Skjolsvold (1956) reported no archaeological evidence of 

 prehistoric occupancy of the Galapagos other than temporary or 

 seasonal visits, and no preceramic contact. With a long reproductive 

 time lag and no special defense against man, the giant tortoises 

 must have been especially vulnerable to human predation. This may 

 explain their early demise compared to the rest of the fauna in Cuba 

 (Williams, 1952a). The Galapagos and Plana Key exceptions to the 

 generalized extinction model (Fig. 6) indicate that it will apply only 

 to regions permanently inhabited by prehistoric man. 



CLIMATIC INDICATORS, EXTINCTION, AND MAN 



"A hypothesis which implies that practically all the important 

 fossil forms had existed until a comparatively Recent date and then 

 become extinct in a geologically short period of time had seemed 

 equally improbable to the writer; and yet it is to such a conclusion 

 that a study of the evidence leads" (Romer, 1933). Flint (1957), 

 Osborn (1936, pp. 1512-1513), and Sauer (1944) are also among 

 those who indicate that prehistoric man was the principal agent of 

 late Pleistocene extinction. If circumstantial evidence points to man, 

 it does not reveal his methods. Sauer's fire-drive hypothesis (1944) 



