The Influence of Growth Rate on Age and Body Size at Maturity in Female Snapping Turtles (Chelydra serpentina)

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Abstract
Growth of female snapping turtles (Chelydra serpentina) in Algonquin Provincial Park, Ontario, Canada, was documented both from recapture records of marked individuals and from reconstructions of growth rates using growth lines on the carapace. Recaptured hatchlings did not grow between hatching and the first spring posthatching, but they grew an average of 1 cm yr-1 during the next 3 yr. Mean age at first enlargement of ovarian follicles of immature females was estimated 11-13 yr. Mean age at first nesting was estimated at 17-19 yr. Several females observed nesting for the first time were older and larger than expected from these estimates, but were smaller and younger than the average adult female in the population. Half of all adult females captured between 1976 and 1985 did not increase carapace length detectably in that time. These nongrowing females were larger on average than were growing females. Females in this northern population reach reproductive maturity at a larger size and greater age than do females in other populations of snapping turtles. This suggests that age at first reproduction is less important to reproductive success than is female body size. Larger body size may increase fecundity and improve ability to survive over winter.