Growth of the turtle Chrysemys scripta under constant controlled laboratory conditions

The purpose of this study was to determine 1) growth of the turtle shell and change in weight under constant controlled laboratory conditions and 2) whether under these constant conditions there were seasonal changes. Fifty unfed refrigerated eight-week-old hatchling turtles Chrysemys scripta were received in October and maintained in aquaria with 16 hours of artificial light and eight hours of darkness, at 24-27 degrees C and a humidity of 30% and fed twice weekly. Gross linear measurements of the width and length of the plastron and carapace, and total body weights, were taken at eight weeks and thereafter at about six-week intervals. During the two-year period the mean increase of the plastron length was from 30.79 +/- 0.19 mm to 68.32 +/- 1.58 mm, plastron width from 24.23+/- 0.20 mm to 50.43 +/- 1.03 mm; carapace length from 32.47 +/- 0.24 mm to 75.21 +/- 1.82 mm, carapace width from 31.81 +/- 0.28 mm to 67.12 +/- 1.29 mm, and body weight from 6.94 +/- 0.15 gm to 80.63 +/- 5.02 gm. Calculated daily percent changes revealed that strongly correlated with its value at 786 days of age. No seasonal differences in growth were noted between the summer and winter periods when turtles would enter winter dormancy in certain natural environments. Environmental factors are reflected in the growth of the turtle.