This Penguin’s Amazing Sleep Pattern: 4-Second Microsleeps, Thousands of Times a Day

Many of us are familiar with the experience of dozing off while reading or working at a computer. Birds, too, are known to indulge in these ‘microsleeps,’ and one particular species seems to have mastered the art of short and frequent slumbers.

Chinstrap penguins (Pygoscelis antarcticus) take more than 10,000 brief naps per day, lasting an average of just 4 seconds each, according to researchers. These short bursts of sleep, totaling over 11 hours daily, appear to serve some of the essential functions of rest, as revealed in a study published in Science.

The study focused on 14 penguins nesting on King George Island, Antarctica. Over a 10-day observation period, the birds never entered into prolonged sleep, with the lengthiest nap recorded being a mere 34 seconds. Co-author Paul-Antoine Libourel, a sleep ecophysiologist at the Neuroscience Research Center of Lyon in Bron, France, finds the most remarkable aspect to be their ability to continuously engage in fragmented sleep, both day and night.

Chinstrap naps

In their quest to gather information on brain activity, the scientists inserted electrodes into the skulls of the penguins. This innovative approach enabled the researchers to pinpoint instances when the birds transitioned into slow-wave sleep, a predominant sleep state shared by birds and humans alike.

Throughout the observation period, penguins exhibited over 600 brief episodes of slow-wave sleep per hour. Notably, these episodes became even briefer and more frequent when the birds were tending to their eggs, suggesting a heightened need for vigilance during incubation, according to the researchers.

Biologist Madeleine Scriba, located in Ettenhausen, Switzerland, acknowledges the existing knowledge that birds, in contrast to mammals, engage in shorter sleep episodes. However, she anticipated that some degree of uninterrupted sleep would be crucial for both physical and mental recovery. “That these penguins are doing very well with such short sleep bouts is really amazing,” she remarks.

Scientists are now delving into the broader implications this discovery holds for our understanding of sleep. Tessa van Walsum, a marine biologist based in London, raises intriguing questions about the restfulness of even frequent naps, given that an average microsleep lasts only around 4 seconds. She ponders, “How would this then build up? And would they find a difference for non-breeding birds?”

The authors propose that if microsleep does prove to have restorative effects, it’s plausible that other creatures might also employ it to obtain rest in situations demanding heightened vigilance. According to Libourel, it remains unclear whether the benefits of microsleep are consistent across various species, including mammals like rats and humans. Nevertheless, the study illustrates that at least one species, the chinstrap penguin, can successfully adopt this sleep pattern and exhibit normal behavior. This suggests the possibility that other species could evolve similar sleep adaptations.

Resources

1. ^JOURNAL Lenharo, M. (2023). This penguin survives on 4-second microsleeps — thousands of times a day. Nature. [Nature]
2. ^JOURNAL Libourel, P., Lee, W. Y., Achin, I., Chung, H., Kim, J., Massot, B., & Rattenborg, N. C. (2023). Nesting chinstrap penguins accrue large quantities of sleep through seconds-long microsleeps. Science, 382(6674), 1026–1031. [Science]

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