Chinstrap penguins take more than 10,000 naps a day.
Many of us are accustomed to experiencing brief lapses into sleep while reading or working on a computer. Birds, too, are known to take in these microsleeps, but there is a particular species that seems to have honed the ability to master the art of short-lived slumbers.
According to a new study, breeding chinstrap penguins take more than 10,000 naps a day, with each nap lasting an average of four seconds. Employing this strategy, the animals amass approximately 11 hours of sleep daily, challenging the conventional human observation that sleep fragmentation is detrimental to sleep quality.
The study that was published in Science, The authors studied 14 penguins nesting in a colony on King George Island, Antarctica. Over 10 days of observation, the birds never engaged in prolonged sleep. The longest nap registered was 34 seconds.
"This is what was most striking and interesting-the fact that they can deal with sleeping in a fragmented way continuously, day and night," says co-author Paul-Antoine Libourel, a sleep ecophysiologist at the Neuroscience Research Center of Lyon in Bron, France.
According to Nature magazine, to collect data on brain activity, the researchers implanted electrodes inside the penguins' skulls. This allowed the scientists to identify when the birds entered a state of slow-wave sleep, which is the dominant form of sleep in birds and also occurs in humans.
Penguins engaged in more than 600 short bouts of slow-wave sleep per hour. These bouts became even shorter and more frequent when the birds were caring for eggs, perhaps because they needed to be more alert while incubating, the researchers say.