Napping while ruminating: How do reindeer sleep?

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“There are extreme conditions in the reindeer habitat. In the Arctic winter it freezes and the reindeer have difficulty finding food,” explained Melanie Furrer from the University Children’s Hospital Zurich in an interview with the Keystone-SDA news agency. To prepare for this, animals spend almost all day in the summer eating.

Furrer and his colleagues wanted to find out what this meant for reindeer sleep. Until now, little was known about the sleeping behavior of animals. “Before us, no one had measured reindeer sleep with EEG,” Furrer said. EEG (electroencephalography) will be used to measure the electrical activity of the brain.

For the study, published Friday in the journal Current Biology, Furrer traveled to Norway with electrodes and small EEG devices normally needed to measure people’s sleep. At the Norwegian Arctic University in Tromsø, they wanted to stick these electrodes on the heads of reindeer to measure their brain waves.

“We didn’t know if it would work,” Furrer said. But it did happen: “When I looked at the first recording, at first I thought I had accidentally caught someone’s recording,” Furrer said.

The researchers conducted these sleep measurements at different times of the year. They found that reindeer sleep about the same amount in winter, summer and fall. “This was unexpected,” Furrer said. “We also thought they slept more in the winter when they were more sedentary and saved energy.”

Measurements of brain waves during rumination explained how reindeer managed to get enough sleep despite increased activity during the summer months: They appeared as if the animals were in deep sleep. “Reindeer save time by meeting their sleep and digestive needs at the same time,” Furrer explained. (SDA)

Source : Blick