Early Growth of Elaphe quadrivirgata from an Insular Gigantic Population

Abstract

Elaphe quadrivirgata on Tadanae-jima Island shows a clear insular gigantism. Based on data from captive animals, we compared growth rates over the first two years after hatching between this population and a conspecific population from the Japan mainland. The purpose of this experiment was to test the hypothesis that early growth rates in snakes in the insular gigantism population are higher than those in conspecific non-gigantic populations under the same feeding schedule. Growth rates in snout-vent length and body mass of Tadanae-jima snakes were not higher than those of main island snakes, and thus, the hypothesis was rejected. This result suggests that the gigantism in E. quadrivirgata on Tadanae-jima Island is not caused by a genetically based modification for rapid growth before maturation. © 2002, The Herpetological Society of Japan. All rights reserved.