Body size and clutch size in the European pond turtle (Emys orbicularis) from central Italy

Abstract

The reproductive biology and ecology of the European pond turtle Emys orbicularis is little known, and available information was previously mainly anecdotal. Morphological data on E. orbicularis are now well documented in most of the known distribution area. Body size in northern populations tends to be larger than in southern populations. There are also indications that clutch size may be larger in northern than in southern European pond turtle populations. Clutch size and reproductive status of a central Italy population were detected by radiography and palpation, respectively, and comparative data were obtained by direct count of intact nest eggs. Reproductive females averaged 13.9 cm and rarely exceeded 15.5 cm carapace length. They produced a clutch size of six, the same number found in intact nests. Nest egg-size averaged 32 mm in length. Egg number was positively associated with female body size, and especially with carapace height.