After being awake for many hours or days, humans and most other mammals are forced to stop all activity and sleep deeply. This involves a total stop of activity, a deactivation of skeletal muscles, and a processing of memories. However, it turns out, not all mammals have this need. Dolphins can stay alert for more than two weeks without going into a complete, deeps sleep. They apparently do this by sleeping with only half of their brains at a time. This makes sense, because if dolphins slept like we do, they would be easy prey to sharks. However, the fact that they can effectively stay awake possibly indefinitely is amazing.
Researchers in San Diego decided to look into Dolphin sleep more in depth in a study they did in 2008. The scientists had two dolphins — a female, Say, and a male, Nay — continuously scan the tanks they were in using echolocation. If they detected objects in the water, they were trained over the course of a year to press a paddle to get fish. The scientists found these dolphins could use echolocation with near-perfect accuracy and no sign of tiring for up to 15 days. And 15 days was just the length of the study; it is possible that dolphins do this their entire lifetimes! It is absolutely amazing the diversity of life on this planet, and the adaptations that animals have.