Chinstrap Penguins Take Over 10,000 Four-Second Naps Daily

Despite fragmented sleep, penguins successfully reproduce and remain vigilant against predators, challenging human understanding of sleep quality.

Chinstrap penguins take more than 10,000 naps a day, each lasting an average of four seconds, accumulating around 11 hours of sleep daily.
The peculiar sleep pattern was identified using remote electroencephalogram (EEG) monitoring and other non-invasive sensors to record brain activity, muscle tone, movement, position and temperature.
The penguins' sleep pattern allows them to remain vigilant while incubating eggs and guarding against predators, such as the brown skua bird.
Despite the fragmented nature of their sleep, the penguins are able to function and successfully reproduce, suggesting that microsleeps can fulfill at least some of the restorative functions of sleep.
Penguins nesting on the fringes of the colony had longer, deeper sleeps than those in the middle, possibly due to the need for increased vigilance against predators.