Chinstrap Penguins' Unusual Sleep Habits Uncovered
With an astounding 7.8 million breeding pairs, chinstrap penguins (Pygoscelis antarctica) are a dominant species in the Antarctic and various South Atlantic islands. During the breeding season, these penguins face constant challenges, from protecting their eggs against predators and rivals to enduring the harsh Antarctic climate.
Researchers from the Neuroscience Research Center in Lyon led by Paul-Antoine Libourel discovered an unexpected solution to these challenges. Chinstrap penguins breeding in these threatening conditions manage to take thousands of short naps per day – up to 10,000, in fact!
These naps are not your typical slumber sessions. The penguins nod off for only four seconds or less during each phase. Yet, they still obtain up to 12 hours of sleep daily, interspersing over 600 such sleep phases per hour. This tactic allows them to deal with the stress of the breeding season without compromising their vital duties.
Exposing Some Surprising Truths
In December 2019, Libourel's team tracked and monitored the behavior and brain activity of wild chinstrap penguins breeding in King George Island's colony, attaching 14 data loggers to the birds. The team supplemented their observations with video recordings and direct observations for 11 days on land and at sea, where the penguins would dive up to 200 meters deep.
Surprisingly, the birds nesting at the colony's edge, exposed to predators and other penguins' aggression, slept 10% more and for an additional second above penguins in the colony's center. This observation suggests that disturbances and aggression from their colony mates have a more significant impact on penguin sleep than the danger from predators.
Swimming and Sleeping
Incidentally, the study conclusively demonstrated that chinstrap penguins could also sleep safely while swimming at sea. Although they slept less during their aquatic escapes, they made up for the missed sleep upon their return to land in brief, 4-second naps.
A New Perspective on Bird Sleep
The team's findings challenged existing beliefs claiming marine birds, including penguins, only slept on land or while swimming at depth. This research provided compelling evidence that penguins have evolved novel strategies to manage their sleep in the face of unique challenges, opening doors to new insights into the physiology of bird sleep.
Researchers from Germany's Max Planck Institute for Ornithology and France's National Centre for Scientific Research collaborated with Libourel's team to publish their groundbreaking findings in the scientific journal Current Biology.
As the team advances their studies in South Korea, they aim to delve further into penguin sleep patterns and its impact on their survival in the challenging environments of the Antarctic and the South Atlantic.
