How a chinstrap penguin sleeps on the job, four seconds at a time.
By Chinstrap Collective
Penguins sleep in tiny pieces. Nesting chinstrap penguins nod off more than 10,000 times a day, and each nap lasts about four seconds. Added up, that is more than 11 hours of sleep a day for each half of the brain, taken without ever leaving the eggs unwatched for long.
Most of us know the power nap: twenty minutes, an alarm, a coffee after. A nesting chinstrap penguin has taken the idea a great deal further. It nods off more than 10,000 times a day, and each nap lasts about four seconds (Libourel and colleagues, Science, 2023). Each one is over in about the time it takes to read this sentence.
That sounds exhausting. But add those seconds up and the total is anything but small: each half of the brain came out at more than 11 hours a day. A long night’s sleep, taken in tiny sips.
What did the scientists find?
The finding comes from a study by Libourel and colleagues, published in the journal Science in 2023 (Science 382:1026). The team recorded the brain activity of 14 wild chinstraps nesting on King George Island, off the Antarctic Peninsula, over 11 days (Technology Networks, 2023). The naps were real sleep: slow-wave sleep, sometimes in both halves of the brain and sometimes in one half at a time (Libourel and colleagues, abstract).
The setting matters just as much as the numbers. In the researchers’ own words, these birds sleep like this while “constantly exposed to an egg predator and aggression from other penguins”. To see what that means, it helps to look at the nest.
Why do penguins sleep in four-second naps?
A chinstrap’s bed is a ring of stones about 40 centimetres (16 inches) wide (Animal Diversity Web). On it, in late November, the pair lays two eggs (Australian Antarctic Division). The parents then share 33 to 36 days of incubation, in shifts that start at 5 to 10 days each and get shorter as hatching approaches (AAD). After hatching, the chicks stay in the nest for 20 to 30 days (Animal Diversity Web).
That is weeks in the same spot, in a crowd. The neighbours are close enough to argue with, and some of them would happily take a stone or two from your nest (we wrote about that in why penguins steal pebbles). And there are enemies in the air: brown skuas nest beside penguin colonies and take eggs and chicks (Australian Antarctic Division).
So a parent that sleeps four seconds at a time is never away for long. The watch eases in the end, when the chicks leave the nest for group nurseries called crèches (Animal Diversity Web).
Do penguins sleep at night?
Not in one long night, the way we do. The study counted sleep per day, not per night: more than 10,000 naps across each day on the nest (Libourel and colleagues, 2023), and over the 11 days of recording the penguins “seemed to never engage in long-term sleep” (Technology Networks).
Off the nest, night is not bedtime either. Chinstraps forage at sea day and night, with their diving effort concentrated near midnight and noon (Australian Antarctic Division). Theirs is a round-the-clock life, on the nest and off it.
Do penguins sleep at sea?
Nobody has the full answer yet; it is one of the open questions of penguin science. The chinstrap study looked at sleep both at sea and on the nest (Libourel and colleagues, abstract), but its headline numbers, the 10,000 naps and 11 hours, describe the nesting birds.
Researchers studying king penguins found that, sleeping on the beach, they react differently to the sounds of predators than to other sounds. The same team notes that king penguins sleep at sea on long diving trips, and hopes to learn how they stay alert out there (Society for Experimental Biology, 2016).
The Unflappable lesson
The chinstrap’s secret is not that it sleeps less. By the scientists’ count, it sleeps for hours. It just doesn’t wait for a quiet moment to do it.
Most of us wait for the noise to stop before we let ourselves rest: the inbox cleared, the house quiet, the list done. The chinstrap’s colony offers no such quiet, and it rests anyway, a few seconds at a time, without taking its eye off what matters for long. We are not recommending 10,000 naps a day to anyone with a job or a toddler. But the next time the world is loud, take four seconds. The penguins would.
Penguin sleep FAQ
How many hours do penguins sleep?
Nesting chinstraps get more than 11 hours a day for each half of the brain, in naps of about four seconds (Libourel and colleagues, 2023).
How long is a penguin nap?
About four seconds on average, more than 10,000 times a day (Libourel and colleagues, abstract).
Why don’t penguins sleep for longer?
On the nest they guard eggs and chicks from brown skuas and from other penguins (AAD; Libourel and colleagues). Short naps keep them close to awake.
Where was the penguin sleep study done?
In a chinstrap colony on King George Island, off the Antarctic Peninsula, with 14 birds recorded over 11 days (Technology Networks).
More Field Notes: Why do penguins steal pebbles? · Chinstrap penguin facts: a day in the life
Sources
- Libourel and colleagues (2023), Nesting chinstrap penguins accrue large quantities of sleep through seconds-long microsleeps, Science 382:1026: more than 10,000 naps a day of about four seconds; more than 11 hours per brain half; sleep recorded at sea and on the nest; “constantly exposed to an egg predator and aggression from other penguins”. Abstract: PubMed 38033080.
- Technology Networks (2023), Chinstrap penguins survive on 10,000 four-second naps every day: King George Island; 14 birds over 11 days; “seemed to never engage in long-term sleep”.
- Coulson (2001), Pygoscelis antarcticus, Animal Diversity Web: nest size; chicks in the nest, then crèches.
- Australian Antarctic Division, Chinstrap penguin: two eggs in late November; shared incubation and shifts; foraging day and night.
- Australian Antarctic Division, Skuas: brown skuas beside penguin colonies.
- Society for Experimental Biology (2016), King penguins keep an ear out for predators: sleeping king penguins and predator sounds; sleep at sea.