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Abstract
The assumption that reptiles exhibit indeterminate growth is widely accepted as a form of conventional wisdom, although the supporting evidence is equivocal. Over time, there has been frequent speculation backed by anecdotal evidence for and against continued growth in large, old, individual reptiles. Although documentation of growth in old, mature reptiles has been reported for some turtle species (e.g., Terrapene ornata, Trachemys scripta), it has been stated as not occurring in others (e.g., Chelonia mydas, Kinosternon subrubrum, Emydoidea blandingii). Definitive evidence of patterns of indeterminate growth in turtles and other reptiles has remained obscure. Several freshwater turtle populations on the Savannah River Site (SRS) in South Carolina contain known-age individuals, many originally captured in the 1960s and 1970s. Since then, over 30,000 turtles have been involved in mark-release-recapture studies. This study investigated whether turtles can continue growing at diminishing rates throughout their lives by using two species of freshwater turtles found on the SRS. Data from both mud turtles (K. subrubrum) and slider turtles (T. scripta) demonstrate unequivocally that some reptiles have indeterminate growth.