Which turtle species can hibernate underwater for up to 5 months?

The painted turtle can hibernate underwater for up to five months. During northern winters, it settles into mud at the bottom of ponds or lakes, sometimes becoming trapped beneath ice while remaining alive in extremely low-oxygen or oxygen-free water.

This survival feat depends on several adaptations. Painted turtles dramatically reduce their metabolism, allowing them to consume very little oxygen. They can also absorb oxygen through their skin and cloaca, commonly described as cloacal respiration. When oxygen runs out, their shells and skeletons help buffer the lactic acid produced by anaerobic respiration.

The duration varies by subspecies and climate. Western painted turtles have survived about 170 days without oxygen, while eastern painted turtles have tolerated roughly 125 days. That is why the species is often described as a champion of underwater overwintering.

A common mix-up is confusing hibernation with simply sleeping underwater. The turtle’s winter state is a prolonged metabolic shutdown, not an ordinary nap; its heart rate, movement, and oxygen needs all fall sharply.