Nesting Penguins Survive on Microsleeps, Study Shows
It's a challenge for all new parents: getting enough sleep while keeping a close eye on their babies. For some penguins, it means thousands of tiny naps a day, researchers have discovered.
Chinstrap penguins in Antarctica need to guard their eggs and chicks constantly in crowded, noisy colonies. So they nod off thousands of times each day — but only for about four seconds at a time — to stay vigilant, the researchers have reported in Science.
These short "microsleeps," totaling around 11 hours per day, appear to be enough to keep the parents going for weeks.
"These penguins look like drowsy drivers, blinking their eyes open and shut, and they do it 24/7 for several weeks at a time," said Niels Rattenborg, a sleep researcher at the Max Planck Institute for Biological Intelligence in Germany and co-author of the new study.
"What's surprising is that they're able to function OK and successfully raise their young," he said.
Chinstrap penguins usually lay their eggs in nests made of small stones in November. As with many other kinds of penguins, mated pairs share parenting duties. One parent tends to the eggs and chicks alone while the other goes off fishing for family meals.
While the adults don't face many natural predators in the breeding season, large birds called brown skuas prey on eggs and chicks. So the parents must be always on guard.
For the first time, the scientists tracked the sleeping behavior of chinstrap penguins in an Antarctic breeding colony by attaching sensors that measure brain waves. They collected data on 14 adults over 11 days on King George Island off the coast of Antarctica.
The researchers did not collect sleep data outside the breeding season, but they believe that the penguins may sleep in longer intervals at other times of the year.
"We don't know yet if the benefits of microsleep are the same as for long consolidated sleep," said co-author Paul-Antoine Libourel. They also don't know if other penguin species sleep in a similar fashion.
