Aerobic metabolism and swimming energetics of the painted turtle, Chrysemys picta.

Oxygen consumption rates (VO2) were measured for painted turtles (Chrysemys picta) swimming in a respirometer at controlled speeds. Sustained specific swimming speeds ranged from 0.75 to 1.52 body lengths (L) per s. Over most of this range endurance exceeded 30 min. VO2 increased curvillinearly with swimming speed (U) and the maximum active rate was 9 times resting (0.26 ml O2/min), and 3 times routine (0.64 ml O2/min). Mass specific metabolic scope was 228 ml O2/(kg.h), similar to that reported for other active chelonians. Cost of transport increased from 3.86 to 5.72 J/(kg.m) over the speed range tested. Swimming costs for rowing painted turtles are greater than those for marine reptiles utilizing anguilliform or lift-producing hydrofoil propulsion. The increased swimming cost for the amphibious painted turtle suggests that morphological specializations permitting effective terrestrial transport, increase energetic expenditures during swimming.