Reindeer found to 'chew' while sleeping

According to a new study, Arctic reindeer ruminate while sleeping, suggesting they dedicate time to digestion even while resting. This reveals that these animals are capable of eating and sleeping at the same time.

According to the study published in Current Biology, this behavior in reindeer demonstrates the ingenious methods animals use to survive under harsh conditions.

It is known that reindeer eat, especially during the summer months when temperatures are high and food is abundant. Like many other herbivores, reindeer ruminate. This process significantly breaks down food and facilitates digestion.

Neuroscientist Melanie Furrer from the University of Zurich, chronobiologist Sara Meier, and other researchers, who conducted the study on whether reindeer ruminate while sleeping, examined four female Eurasian tundra reindeer.

The researchers were actually looking for brain waves that occur during non-REM sleep. These waves appeared while the reindeer were ruminating, but the chewing motion itself made it difficult to observe whether the signal was the same as in a normal sleep session.

Nevertheless, other signs indicated that rumination was taking place during sleep.

On the other hand, it was reported that the reindeer were mostly calm and their eyes were closed while performing this chewing motion. It was also difficult to disturb these ruminating reindeer. Here, the researchers found that the time spent chewing reduced the time spent in resting sleep.

In other studies, it is known that there are signs that reindeer sleep with both sides of their brain while chewing. This study on reindeer is considered important for understanding that sleep can be divided into different types within itself.