Incubation Temperature and Sex Ratio of the Veiled Chameleon (Chamaeleo calyptratus)

Eggs from five clutches of Chamaeleo calyptratus were incubated at 25, 28, and 30°C during the period of sex determination. Sex ratios were slightly biased toward females at all temperatures but did not differ statistically from the expected 1:1 ratio of males and females. Egg survival was sufficiently high that sex-biased temperature-induced mortality cannot account for the lack of departure from 1:1 sex ratios. I conclude that the veiled chameleon has genetic sex determination (GSD) and that anecdotal accounts of temperature-dependent sex determination (TSD) for this species, and other chameleons are likely to reflect reporting or statistical bias.