Getting enough sleep is a challenge for almost everyone. In the case that you can't get at least seven hours off sleep at night, taking a cat nap is a great way to catch up on rest. While felines are most commonly recognized as avid daytime snoozers, there's a certain bird that has taken napping to another level. The charming chinstrap penguin—named after its distinct black marking underneath its beak—has an incredible microsleep schedule. Rather than rest for a long period of time, it sustains itself with over 10,000 naps, each of which lasts only about four seconds.
While microsleeping in such small increments does not work for humans, chinstrap penguins appear to thrive on this sleep cycle. By fading in and out of these brief naps, they sleep about 11 hours in total each day. Scientists believe that due to the extreme conditions in living in islands off of Antarctica, this sleep schedule may have been adapted to keep the penguins on near-constant watch for predators and to protect their vulnerable nests and eggs. “What is really weird is that the penguin can sustain this in-between wake and sleep state constantly,” explains co-author Paul-Antoine Libourel. “Only by constantly recording brain activity, for days, have we been able to highlight this interesting sleep phenotype.”
It is hard to even tell when chinstrap penguins fall into a state of sleep, as they simply blink lazily before appearing alert again. The research being conducted on this species also highlights how not all species rely or even benefit from long, uninterrupted sleep cycles. “Sleep provides a lot of benefits, but we don’t know whether it’s the same benefits for all species,” Libourel adds. “And we don’t know at what point we can disturb sleep, with or without cost to the animal.”
A sleep physiologist from the University of Oxford, Vladyslav Vyazovskiy, proposes that the chinstrap penguins' rapid sleep cycle also aids the colony as a whole. While some sink into a short slumber, others remain awake, ensuring that the group remains somewhat vigilant to danger. Scientists also found that the sleep duration and quality varied based on where the birds were located in the colony, with birds on the periphery dozing off for longer periods of time, most likely due to the stress of being on guard for predators. “Wake quality affects sleep quality,” Vyazovskiy says. “So maybe the birds on the periphery need to be extra vigilant, and they get tired, and then they sleep a bit longer and in a deeper way.”
Although the microsleep schedule has proven to be a winning strategy for chinstrap penguins, it is certainly a unique adaptation that doesn't work for everyone. These studies provide more evidence on how different species lean into particular sleeping habits to survive in ever-changing environments.
A 4-second nap sounds like nothing to us humans, but chinstrap penguins are able to sustain themselves by dozing off in tiny increments over 10,000 times per day.
h/t: [Smithsonian Magazine]