The Comparative Reproductive Physiology of Sea Turtles

Although the reproductive ecology of marine turtles has beenthe subject of numerous long-range studies, the reproductivephysiology of these unique animals is little known. Recently,however, preliminary anatomical and endocrinological studieshave provided a good basis on which to begin to attempt to explainseveral of their unusual biological systems. New findings relatedto the anatomy of Chelonia mydas and Lepidochelys olivacea arepresented. The female, although having a very massive pair ofsimultaneously functioning ovaries, appears in most ways verysimilar to other chelonians. Corpora hemorrhagica, corpora luteaand corpora atretica from active ovaries are briefly described.Ovulation coincides with a luteinizing hormone and progesteronesurge. Sperm are probably stored for the season after a singlemating period which appears to occur prior to the first ovulation.Males may also cycle and mating as well as nesting are seenas more or less seasonal. The seasonality could be controlledin part by melatonin or other endocrines from the sea turtle'smassive pineal complex. A hypothetical model for reproductionis presented in hopes of stimulating interest in physiologicalapproaches to the study of marine turtle reproduction.