Reindeer seem to snooze all through the day whereas chewing their cud. This can be an adaptation to their Arctic habitat, the place meals is plentiful in the summertime and so they should continually eat to achieve sufficient weight to outlive the winter.

To assist break down the fibrous crops that make up their eating regimen, reindeer ruminate – that’s, they regurgitate meals from their abdomen again into their mouth for further chewing. And so they usually tackle a trance-like stare as they chomp. “You’ll be able to form of see it of their face, they’re a bit gone,” says Gabriela Wagner on the Norwegian Institute of Bioeconomy Analysis. “However no person knew in the event that they had been really asleep as a result of nobody has ever measured the brainwaves of reindeer earlier than.”

Wagner and her colleagues used an electroencephalograph (EEG) – steel electrodes hooked up to the heads of 4 captive Eurasian tundra reindeer (Rangifer tarandus tarandus), which recorded electrical pulses of their brains over the following few days as they ate, slept and moved round.

The reindeer’s brainwave patterns revealed that, when ruminating, they had been in a lightweight stage of sleep generally known as non-REM sleep, suggesting the animals can recharge whereas chewing their cud. “It seems very very similar to human sleep – it’s received the identical levels of sleep spindles and sluggish wave exercise,” says Wagner, describing bursts of mind exercise seen on the EEG. Additionally they discovered that the extra time the reindeer spent ruminating, the much less they wanted extra relaxation.

Wagner suspects such a multitasking would possibly assist the animals get sufficient relaxation throughout the summer time once they spend nearly all their time feeding in preparation for winter. “This appears to be an ideal adaptation to the Arctic, the place you simply have a really brief interval of the yr when you need to eat on a regular basis to get fats,” she says.

Resting whereas ruminating can also clarify why, in contrast to most different species that sleep extra in winter, reindeer seem to sleep the identical quantity whatever the season.