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 they usually should continuously eat to achieve sufficient weight to outlive the winter.

To assist break down the fibrous vegetation that make up their weight loss program, reindeer ruminate – that’s, they regurgitate meals from their abdomen again into their mouth for additional chewing. And so they typically tackle a trance-like stare as they chomp. “You’ll be able to kind 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 have 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) – metallic 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 have been in a light-weight stage of sleep often called non-REM sleep, suggesting the animals can recharge whereas chewing their cud. “It seems to be very very similar to human sleep – it’s bought the identical levels of sleep spindles and gradual 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 further relaxation.

Wagner suspects such a multitasking may assist the animals get sufficient relaxation in the course of the summer time after 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 quick interval of the yr when it’s important to eat on a regular basis to get fats,” she says.

Resting whereas ruminating may additionally clarify why, not like most different species that sleep extra in winter, reindeer seem to sleep the identical quantity whatever the season.