Study: Penguins take up to 10,000 short naps a day
The almost eight million breeding pairs of the penguin with the scientific name Pygoscelis antarctica live in the Antarctic and on some islands in the South Atlantic. When breeding, the female and male take turns. Alone on the nest, they must constantly protect their eggs from birds of prey, the brown skuas. In addition, the parent birds have to defend their nests against other penguins trying to steal nest material.
This constant tension is the reason for the unusual sleeping behavior of the chinstrap penguin: during breeding, the parent birds accumulate large amounts of sleep through thousands of microsleep phases, as the researchers have discovered. They usually do not nod off for more than four seconds at a time, but still get up to twelve hours of sleep through over 600 sleep phases per hour - a total of over 10,000 per day.
In December 2019, the research team led by Paul-Antoine Libourel from the Neuroscience Research Center in Lyon recorded the behaviour and brain activity of wild chinstrap penguins breeding in a colony on King George Island in the Antarctic. To measure their brain activity, they equipped 14 birds with specially designed data loggers. This was supplemented by video recordings and direct observations.
These activities of the birds were recorded for eleven days on land and at sea, where the penguins dived to a depth of 200 meters. The researchers then investigated how nesting at the edge of the colony, where the penguins are exposed to birds of prey, affects penguin sleep compared to the center of the colony.
The surprising result: the birds at the edge of the colony sleep ten percent more and one second longer than the birds in the center of the colony. Disturbances and aggression from other penguins within the colony therefore have a greater influence on sleep than the danger from predators.
The researchers also showed in the study that penguins can also sleep swimming at sea. Overall, they slept significantly shorter at sea than on land. After returning to land, some of the missed sleep was made up for, albeit only in phases lasting an average of four seconds.
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Source: www.stern.de
