Penguins nap more than 10,000 times a day – 12/01/2023 – Science

Along the rocky, ice-free coast of Antarctica, millions of chinstrap penguins form bustling breeding colonies—chaotic, noisy, and, yes, smelly—each year, laying eggs in November that hatch in late December and January. .

Protecting their nests is a serious matter for these penguins, as brown gulls lie in wait. Therefore, falling asleep while working can spell doom for the eggs and, of course, the chicks. But this species, scientists announced this Thursday (30), has developed an ingenious way to get enough sleep without compromising vigilance.

Researchers have documented extreme sleeping behavior in these flightless, medium-sized birds. Instead of sleeping for prolonged periods while nesting, chinstrap penguins nap thousands of times a day — for only about four seconds at a time — and meet their sleep needs cumulatively, accumulating about 11 hours per day.

“They show an unexpected adaptation of sleep, a compromise between the need to sleep and the need to be awake,” said Paul-Antoine Libourel of the Neuroscience Research Center in Lyon, France, lead author of the research published in the journal Science .

“This has not been documented before,” said behavioral ecologist and study co-author Won Young Lee of the Korea Polar Research Institute in Incheon.

The researchers collected data from 14 penguins incubating eggs in a colony of approximately 3,000 breeding pairs on Antarctica’s King George Island in December 2019. They measured electrical activity in the brain — evidence of sleep activity — using a method called electroencephalography.

Additionally, they filmed the birds and used other biorecording devices, such as GPS monitors and accelerometers, to track their location and body movements.

While guarding their nests, chinstrap penguins engage in “microsleeps” — interruptions of wakefulness lasting a few seconds, with eye closure and sleep-related brain activity — on average about 10,000 times a day and sometimes up to 15,000 times. Sleep occurs while standing or lying down.

Sleep is a precious commodity for people and the animal kingdom, due to its restorative value and other purposes. In people, microsleeps can be dangerous — for example, when driving. But not for chinstrap penguins.

“Penguins do not show any obvious negative consequences of sleep fragmentation,” Libourel said. “Because birds can reproduce and forage efficiently, we believe that the function of sleep can be fulfilled even when sleep is disturbed in this way.”

Lee said other animals may use similar sleep strategies, although it has not yet been documented.

Chinstrap penguins are so named because of the band of black feathers under their chin. Adults are around 70 to 80 cm tall and weigh around 3 to 6 kg. They are one of the most abundant penguins in the Antarctic region.

They generally remain with the same breeding partner year after year, in a kind of marriage. Females usually lay two eggs in a circular nest made of rocks, and the young hatch about 37 days later. During this period, males and females share parental responsibilities, with one continually guarding the eggs or chicks while the other forages for food in the freezing ocean for several days.

Also during this period, seagulls prey on penguin eggs, especially on the outskirts of a colony. Chinstrap penguins also have to defend their nests from intrusions by other penguins in the crowded and noisy colony.

“It’s an incredible landscape, constantly changing, not that cold, with an average temperature of around 1ºC. But sometimes very windy, with snowfall,” Libourel said.

“As a field biologist, I have been observing penguins since 2014. The penguin colony is located near the coast. It is quite smelly due to penguin feces. Also, it is very noisy with penguin calls,” Lee added.