Growth and Morphometrics of the Box Turtle, Terrapene c. carolina

Abstract

Growth of box turtles (Terrapene c. carolina) in a bottomland forest in Maryland was studied over a period of years (1944-1981). A bivariate analysis of age related growth showed that between 8 and 13 yr, male turtles grew at an average rate of 6.7% per yr in carapace length, whereas females grew at 5.3% per yr. Both males and females grew considerably more slowly between 14 and 19 yr, males at 2.3% per yr and females at 3.4% per yr. Growth slowed still more in the twenties. Growth in the six other dimensions that were measured provided additional comparisons. Allometric analysis of the different carapace and plastron dimensions showed that among males length increased proportionally more than either width or height and that width increased more than height. Among females, only the greater increase of length than of width was statistically significant. Fully grown males were larger than females in all dimensions except height. Differences from the normal scutal pattern occurred in 16.8% of fully grown males and 18.4% of the females.