How does an African lungfish manage to survive for long periods of time outside of water?

African lungfish have some fascinating adaptations. They have two lungs, and can breathe air. This is a vital feature, since they live in flood plains in waterways that often dry up. To manage this life-threatening situation, the lungfish secretes a thin layer of mucus around itself that dries into a cocoon. It can live out of water in this cocoon for up to a year, breathing through its lungs until rains refill its waterway.

The African lungfish also hibernates in water. It digs 1-9 inches into the soil and debris at the bottom of its waterway, then wiggles in the mud to create a bulb-shaped chamber and rests there with its nose pointing upward. Its metabolic rate slows down, and the nutrients it needs to survive come from breakdown of its muscle tissue. It can remain up to 4 years in this state.