Chinstrap penguins take 10,000 naps per day.
Chinstrap penguins have 10,000 naps each day
The Antarctic bird has thousands of naps lasting four seconds each to enable them to sleep for more than 11 hours every day.
The penguins need to constantly safeguard their eggs and chicks from predators for days on end and use "microsleeps" to get a full day's rest while keeping vigilant.
The study authors from the Neuroscience Research Centre of Lyon and the Korea Polar Research Institute wrote in their paper, published in the journal Science: "We investigated sleep in wild chinstrap penguins, at sea and while nesting in Antarctica, constantly exposed to an egg predator and aggression from other penguins.
"The penguins nodded off more than 10,000 times per day, engaging in bouts of bihemispheric and unihemispheric slow-wave sleep lasting on average only four seconds, but resulting in the accumulation of more than 11 hours of sleep for each hemisphere.
"The investment in microsleeps by successfully breeding penguins suggests that the benefits of sleep can accrue incrementally."