WASHINGTON (AP) — It's a challenge for all new parents: getting enough sleep while keeping a close eye on their newborns. Researchers discovered that for some penguins, this means thousands of mini-catnaps a day.
Chinstrap penguins in Antarctica must protect their eggs and chicks around the clock in crowded, noisy colonies. So they nod thousands of times every day to stay alert, the researchers said — but only for about four seconds at a time. reported on thursday In science magazine.
These short "microsleeps" of about 11 hours per day appear to be enough to keep parents active for weeks.
"These penguins look like drowsy drivers, opening and closing their eyes, and they do so 24/7 for several weeks," said co-author Niels Rattenborg, a sleep researcher at the Max Planck Institute for Biological Intelligence in Germany. " Author of the new study.
"The surprising thing is that they are able to function properly and raise their children successfully," he said.
Chinstrap penguins, named for the thin line of black facial feathers resembling a chinstrap, usually lay their eggs in pebble nests in November. Like many other types of penguins, mating pairs share parenting duties. One parent single-handedly cares for the eggs and chicks while the other goes fishing for the family's food.
While adults do not face many natural predators during the breeding season, large birds called brown skua prey on the eggs and small fluffy brown skua chicks. Other adults may also attempt to steal pebbles from the nest. Therefore, dedicated parents should always remain alert.
For the first time, scientists tracked the sleeping behavior of chinstrap penguins in an Antarctic breeding colony by implanting sensors that measure brain waves. They collected data on 14 adults over 11 days on King George Island off the coast of Antarctica.
The idea for the study came when Won Young Lee, a biologist at the Korean Polar Research Institute, observed breeding penguins repeatedly blinking their eyes and apparently nodding during their long days of field observations. But the team needed to record brain waves to confirm that they were sleeping.
"For these penguins, microsleeps have some restorative function—if not, they couldn't tolerate," he said.
The researchers did not collect sleep data outside the breeding season, but they estimate that penguins may sleep for longer periods at other times of the year.
"We don't yet know whether the benefits of microsleep are the same as those of longer consolidated sleep," said Paul-Antoine Libourel, co-author and sleep researcher at the Neuroscience Research Center of Lyon in France. They also don't know whether other penguin species sleep in a similarly fragmented manner.
Scientists have documented some other animals with special sleep adaptations. while flying, frigatebirds can sleep half of their brain at a time, and Northern elephant seals can take a nap For example, for 10 or 15 minutes at a time during deep dives.
But researchers say chinstrap penguin microsleeps appear to be a new extreme.
“Penguins live in a highly stressful environment. They breed in crowded colonies, and all their predators are there at the same time,” said Daniel Paranhos Zitterbart, who studies penguins at Woods Hole Oceanographic Institution in Massachusetts and was not involved in the study.
Microsleeping is "an amazing adaptation" to enable constant alertness, he said.
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