Related Experiment Video
Updated: May 11, 2026

Automated Measurements of Sleep and Locomotor Activity in Mexican Cavefish
Published on: March 21, 2019
[Sleep in cetaceans]
Abstract:
Over the course of evolution, cetaceans have adapted to sleep in conditions that can be considered extreme for warm-blooded and air breathing animals. Studies of sleep in cetaceans have led to the discovery of an unusual type of sleep called unihemispheric slow wave sleep. The ability of cetaceans to sleep during swimming and to close only one eye at a time are two other features of their sleep, directly related to its unihemispheric nature. Paradoxical sleep in the form it is recorded in all terrestrial mammals is absent in cetaceans. The pattern of sleep in cetaceans allows them to 1) monitor the environment for predators and conspecifics to maintain group coherence, 2) surface regularly for breathing and 3) maintain effective thermoregulation.
Related Concept Videos
Stages of Sleep
Before sleep begins, in wakefulness, the brain exhibits primarily beta waves, which are high in frequency and low in amplitude, indicating alertness...
Sleep-Wake Cycles
NREM Sleep
NREM sleep comprises four progressive stages that seamlessly merge:
REM Sleep Behavior Disorder
RBD is significantly associated with...
Understanding Sleep
The circadian rhythm, a nearly 24-hour cycle, is deeply influenced by environmental light cues. Light exposure directly affects the hypothalamus, which in turn regulates...

