It's a challenge for all new parents: Getting enough sleep while keeping a close eye on their newborns. Researchers have discovered that, for some penguins, it means thousands of mini-catnaps a day. Chinstrap penguins in Antarctica need to guard their eggs and chicks around-the-clock 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. That’s according to a study published Thursday in the journal Science. These short “microsleeps,” totaling around 11 hours per day, appear to be enough to keep the parents going for weeks. “I'm not very surprised (about the results of the study), because we do see that similar behavior here,” said Lindsay Ireland, a penguin zookeeper at the Detroit Zoo in Royal Oak, Michigan. “They're very active first thing in the morning when the lights come on and then you'll see them, after they eat they'll kind of take a series of naps or they'll just be a little more sedentary in their location, whether it's on land or in the water.” Chinstrap penguins are named for the thin line of black facial feathers resembling a chinstrap. They usually lay their eggs in pebble nests 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 small fuzzy gray chicks. Other adults may also try to steal pebbles from nests. So, the devoted 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 idea for the study was hatched when a biologist at the Korean Polar Research Institute noticed breeding penguins frequently blinking their eyes and apparently nodding off during his long days of field observations. But the team needed to record brain waves to confirm they were sleeping. The researchers did not collect sleep data outside the breeding season, but they hypothesize that the penguins may sleep in longer intervals at other times of the year.