Book 30, Question 62
Why do painted turtles stack up on logs to sunbathe?
Turtles are cold-blooded, so they cannot make their own body heat.
On a sunny day, painted turtles climb onto logs and rocks to warm up, sometimes piling on top of each other. The heat helps them digest food and stay active. Basking also dries their shells, which helps keep algae from growing on them. At the slightest sign of danger, they slip back into the water with a plop.