Methods to Study Reproduction

Abstract

The anatomical, histological, endocrinological, physiological and behavioural methods used to study reproduction of chelonians are principally the same as for other vertebrates. The box-like armour of chelonians, however, makes access to reproductive organs more difficult than in most other groups. Hurdles to reproductive biological investigations include difficulties in finding animals (or certain life stages) on a regular basis over the whole year, difficulties in readily assessing reproductive conditions in live animals (some species are even difficult to sex externally) and difficulties in obtaining blood or tissue samples. Reviews and comprehensive descriptions of general techniques for chelonian life history studies (including collecting, trapping, tracking, marking techniques, measurements and stomach flushing for dietary analyses) can be found in Gibbons (1990b), Graham (1979) and Wilbur and Morin (1988); details are beyond the scope of this book and are not presented here. Beyond the scope of this book also is the description of reproductive physiological laboratory techniques. This account deals primarily with methods to obtain reproductive biological data during field investigations.