In humans, falling asleep for a few seconds is a clear sign of insufficient sleep and can be dangerous in some situations, such as driving. But a new study published Thursday shows that chinstrap penguins nap thousands of times a day, accumulating daily sleep requirements of more than 11 hours in short bursts that last only four seconds on average.

According to the authors of the article ScienceFlightless birds may have developed this feature due to their need to be constantly alert. The results suggest that, contrary to previous assumptions, the benefits of sleep may gradually increase, at least in some species, the researchers say.

Belted penguins (Pygoscelis antarcticusThe penguin, named for the thin band of black feathers that extends from ear to ear, may be the most common penguin species. Their current population is estimated at approximately eight million breeding pairs, located mainly on the Antarctic Peninsula and the South Atlantic islands.

During nesting, solitary penguins must watch over their eggs and protect them from birds of prey called skunks; Meanwhile, their wives go on foraging trips lasting several days. They also have to protect their nest from other penguins who might try to steal the nest material. When the penguin partner finally returns, the two switch roles.

A team led by Paul-Antoine Libourel of the Lyon Neuroscience Center implanted electrodes in 14 birds in a colony on King George Island in December 2019. They recorded electrical activity in the brain and neck muscles and used accelerometers and GPS to study body movements and positions.

Combined with several days of video recordings and direct observations, they were able to detect numerous features.

Penguins slept standing or lying down for an average of 3.91 seconds to incubate their eggs. In total, they slept more than 10,000 times a day. Penguins in the periphery slept longer and deeper than those in the center; This may be explained by excessive noise and physical shocks occurring in the middle of the colony or by the increased risk of theft of nesting material.

Although scientists haven’t directly measured whether the birds reap the restorative benefits of sleep, the fact that the penguins are successfully breeding leads them to believe so, and moments of neural silence create windows for rest and recovery. But in humans, sleep-disrupting conditions such as sleep apnea affect cognitive function and can even trigger neurodegenerative diseases such as Alzheimer’s disease.

“Thus, what is abnormal in humans may be quite normal in birds or other animals, at least under certain conditions,” scientists Christian Harding and Władysław Vyazowski wrote in a related commentary.