Extreme Sleep Behavior of Antarctic Penguins

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

Penguins are birds that cannot fly but use their wings for swimming. They live in or near the Antarctic.

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.

A study on the findings recently appeared in the publication Science.

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 is a sleep researcher at the Max Planck Institute for Biological Intelligence in Germany. He helped write the new study. He said these penguins blink "... their eyes open and shut, and they do it 24/7 for several weeks at a time."

"What's surprising is that they're able to function okay and successfully raise their young," he said.

Chinstrap penguins usually lay their eggs in November in nests made up of small rocks. As with many other kinds of penguins, mated pairs share parenting responsibilities. One parent usually watches the eggs and chicks alone while the other goes off fishing for family meals.

Adult penguins do not face many natural predators 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 nests. So, penguin parents must always be on guard.

For the first time, scientists followed the sleeping behavior of Chinstrap penguins in an Antarctic mating colony. 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 is a biologist at the Korean Polar Research Institute. He thought of the idea for the study when he saw mating penguins often blinking their eyes and possibly sleeping during his long days of field observations. 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 did not collect sleep data outside the mating season. But they suspect that the penguins may sleep for longer periods at other times of the year.

Paul-Antoine Libourel is a sleep researcher at the Neuroscience Research Center of Lyon in France. He also helped write the study. He said scientists do not yet know if the gains from microsleep are the same as gains from longer periods of time. Scientists also do not know if other kinds of penguins sleep in such short periods.

Researchers have documented a few other animals with special sleeping adaptations. For example, frigatebirds can sleep with one half of their brain at a time while flying.

But researchers say the Chinstrap penguin microsleeps appear to be a new extreme.

Daniel Paranhos Zitterbart studies penguins at the Woods Hole Oceanographic Institution in Massachusetts. He was not involved in the study. He noted that penguins mate in crowded colonies and their predators are around at the same time. He described microsleeping as "an amazing adaptation" that permits the penguins to be nearly always on guard.

I'm Gregory Stachel.

Christina Larson reported this story for The Associated Press. Gregory Stachel adapted it for VOA Learning English.

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blink – v. to close and then open your eyes very quickly

shut – v. to close (something)

nest – n. the place where a bird lays its eggs and takes care of its young

predator – n. an animal that lives by killing and eating other animals: an animal that preys on other animals

restore – adj. large in amount, size, or number

adaptation – adj. having the ability to make a person feel strong or healthy again

amazing – adj. causing great surprise or wonder