Do sharks swim while they sleep?

One of the most widely disputed nuances of sharks is if they sleep or not. ... When observed in their natural environment Nurse Sharks were seen to remain motionless or “resting” on the bottom of the ocean floor. ... While some species of sharks do need to swim constantly, this is not true for all sharks. read more

Florida Program for Shark Research Director George H. Burgess discussed the lack of knowledge around shark sleep with the Van Winkle's blog and says some sharks may rest during "yo-yo swimming," when they actively swim to the surface but rest as they descend. read more

In response to a question about whether or not sharks sleep and, if they do, how do they swim while unconscious, I wrote: Sleep is one of the last bastions of mystery that Science has yet to conquer. Despite several centuries of study, speculation, and debate, we still really don't know what sleep is or why we need to 'shut down' periodically. read more