An overview of the past, present, and future of the Cuban Boa, Chilabothrus angulifer (Squamata: Boidae)

A top terrestrial predator on an oceanic island

Abstract

On oceanic islands, where carnivorous mammals are frequently absent, the niches of large predators are often filled by raptors and reptiles. Cuban Boas (Chilabothrus angulifer), along with Cuban Crocodiles (Crocodylus rhombifer) and large birds of prey, were the top predators in the Cenozoic terrestrial ecosystems of Cuba until the arrival of Homo sapiens in the region about 6,000 years ago. This ecological scenario of large boas in the genus Chilabothrus functioning as top predators in terrestrial ecosystems is repeated on each of the largest islands of the Greater Antilles. The evolution of very large size in the Cuban Boa is best explained as phyletic giantism (Cope’s Rule), although other paleo-ecological selective factors might have maintained or even accentuated the evolutionary trend toward large body size (insular giantism). However, this seems not to be the case for all species of Chilabothrus, since the evolution of a small body size is repeated in several lineages, a phenomenon that is best explained by autamorphic nanism (Island Rule). Unfortunately, the negative effects of humans on natural populations of the Cuban Boa apparently have induced a dramatic reduction in maximum body size even during the relatively short period since the first reliable measurements were recorded in the 19th century. Such a reduction in body size is consistent with that reported for other West Indian reptiles and is probably indicative of rapid evolution in response to a highly modified environment with new selective pressures.