Tail Autotomy in the Central American Spiny Rat, Proechimys semispinosus

Abstract

We studied the effects of sex, age, density and island size and isolation on tail autotomy within twelve island populations of the Central American spiny rat (Proechimys semispinosus, Rodentia: Echimyidae). The proportion of individuals losing their tail differed among islands but not between sexes. Most P. semispinosus lost their tail as adults. Population density and island size and isolation did not influence tail autotomy. Overall tail loss (8.0%) was lower than that previously reported in other populations of P. semispinosus. We suggest that low frequencies of tail loss were due to low rates of attack by mammalian predators typical of small, isolated islands and that differences among islands were due largely to the occasional appearance of transient predators such as coatis (Nasua narica). However, we caution against using tail loss as an index of predation because such a link has not been established yet.