Almost all new parents struggle to get enough sleep while caring for their newborns. For some penguin (企鹅) parents, though, periods of sleep are especially short.

Researchers recently found that Chinstrap penguins only sleep for about four seconds at a time in order to protect their eggs and newborn chicks. They do this thousands of times throughout the day. The short "microsleeps" total around 11 hours each day. The microsleeps appear to be enough to keep the parents going for many weeks.

Niels Rattenborg, a sleep researcher at the Max Planck Institute for Biological Intelligence in Germany, said, "What's surprising is that the penguins are able to function okay and successfully raise their young."

Chinstrap penguins usually lay their eggs in November in nests made up of small rocks. Mated (交配的) pairs share parenting responsibilities. One parent usually watches the eggs and chicks alone while the other goes off fishing for family meals. Adult penguins don't face many natural enemies in the mating season. But large birds called brown skuas eat the penguin eggs and small chicks. Other adult penguins may also try to steal the small rocks from the nests, so penguin parents must always be on guard.

For the first time, scientists followed the sleeping behavior of Chinstrap penguins. They did this by attaching devices that measure brain waves. They collected data on 14 adults over 11 days on King George Island off the coast of Antarctica.

Won Young Lee, a biologist at the Korean Polar Research Institute, thought of the idea for the study when he saw mating penguins often blinking (眨) their eyes and possibly sleeping. But the team needed to record brain waves to confirm the animals were sleeping. "For these penguins, microsleeps have some restorative functions," he said. He added that they would not survive without it.

The researchers didn't collect sleep data outside the mating season. But they suspect that the penguins may sleep for longer periods at other times of the year.