Movements and Seasonal Activity of Atelopus oxyrhynchus (Anura: Atelopodidae) in a Venezuelan Cloud Forest

Abstract

A 13-month field study of Atelopus oxyrhynchus revealed pronounced sexual dimorphism in size, (males averaged 44.1 mm, females 50.8 mm) and negligible growth in adults of both sexes. Through most of the year frogs resided in forest away from water; females occupied a mean area of 32.6 ? 29.9 m2 and males 56.2 ? 79.9 m2. Amplexus occurred as early as December. Migration to the stream did not begin until late April or May but spawning did not take place until May or June. One pair remained in amplexus at least 125 days. Activity on the forest floor was influenced mainly by precipitation.