Author(s)

Erich K. Ritter^1,2

¹Department of Mathematics and Statistics, University of West Florida, Pensacola, FL, USA.
²Shark Research Institute, Princeton, NJ, USA.

It is unknown if resting sharks can sleep, which is also true for gliding ones. Here, a videotaped bull shark is presented that drifted in an uncontrolled manner for 120 seconds while sinking with 0.1 m/second. Several aspects are discussed to determine if the shown behavior reflects the commonly accepted definition of sleep. Additionally, the idea is also discussed if this state might reflect a “quiet waking state” instead of where the shark still maintained some vigilance despite its general appearance.

Drifting, Melatonin, Pineal Gland, Shark, Sleep

Ritter, E. (2020) Is the Shark Just Drifting, or Does It Take a Quick Nap?. Open Journal of Animal Sciences, 10, 40-47. doi: 10.4236/ojas.2020.101004.