A new study has shown that chinstrap penguins take over 10,000 naps daily, each lasting approximately four seconds. This napping cycle is called “microsleeps” or “micro naps.” Microsleep is defined as seconds-long interruptions of wakefulness, including eye closure and sleep-related brain activity. This is seen to also occur in people who experience insufficient sleep. For humans, the effects are much more serious. Falling asleep frequently and uncontrollably in dangerous situations, like when driving, can be catastrophic.
In total, chinstrap penguins sleep for 11 hours a day. Researchers studied 14 chinstrap penguins forced to protect their eggs from skuas, a predatory bird, to determine whether microsleeps can provide sleep functions. The researchers used electroencephalogram (EEG) monitoring to record the penguins’ brain activity, movement, temperature, and muscle tone. The study showed that the penguins in the colony took over 600 microsleeps in an hour.
Penguins split their time between swimming in the ocean and staying near their nests. When at sea scouring for food, penguins do not sleep. They resume their cycle as they return to their nests. Penguins were also seen to take turns taking care of their eggs and offspring, as brown skua constantly attack penguin nests. However, despite the environmental chaos, many scientists have deduced that microsleep may be the default for animals. It should not be criticized for not working for humans. The full extent of benefits from microsleep is yet to be analyzed in future studies. As explained by Vladyslav Vyazovskiy, a neuroscientist at the University of Oxford, the penguins are essentially spending their lives asleep and waking up when necessary.
Sleep ecophysiologist Paul-Antoine Libourel, who manages sleep projects at the Neuroscience Research Center of Leon, confirmed that 75% of sleep in chinstrap penguins lasted less than 10 seconds. He also added that the penguins could “sleep and remain vigilant,” meaning they are able to sustain this intense cycle. Many other animals are unable to fathom the fragmentation of days and hours.
The science of sleep started in the early 1900s when scalp electrodes showed that people produced slower brain waves when sleeping. Studies started to prove that every animal spent some time in their day sleeping, whether they had a brain or not. Sleep studies provided a variety of results, such as human brains shutting down certain functions while asleep. In contrast, certain animals only shut down a side of their brains, such as seals.
This groundbreaking study contrasts previous studies with other penguins. A study in 1984 concluded that little penguins placed in metabolic chambers showed a state of “quiet wakefulness.” This is similar to the chinstrap penguin, except the microsleeps lasted approximately 42 seconds. This is a stark contrast to the 4-second cycles experienced by chinstrap penguins. Authors of the study have stated that “thousands of microsleeps lasting only four seconds is unprecedented, even among penguins.” In another study conducted in 1986, nonbreeding emperor penguins were shown to have fragmented sleep referred to as “drowsiness.” This is similar to microsleeps, but emperor penguins only spent 14% of their day in the “drowsy” state.
Studies have yet to be conducted regarding the physiological aspects of microsleep in penguins. Libourel and other researchers have warned that humans cannot follow the same pattern as sleep functions differently in chinstrap penguins. There remains a “gap” in the understanding of human life and climate change on the sleeping habits of animals. Many scientists concur that sleep studies are effective, and thus should increase in number in the coming decades.
