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 ample in the summertime and so they should always eat to realize 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 further chewing. They usually usually tackle a trance-like stare as they chomp. “You possibly can type of see it of their face, they’re a bit gone,” says Gabriela Wagner on the Norwegian Institute of Bioeconomy Analysis. “However no one 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) – 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 subsequent few days as they ate, slept and moved round.
The reindeer’s brainwave patterns revealed that, when ruminating, they had been in a light-weight stage of sleep generally known as non-REM sleep, suggesting the animals can recharge whereas chewing their cud. “It appears to be like very very like human sleep – it’s acquired the identical levels of sleep spindles and gradual wave exercise,” says Wagner, describing bursts of mind exercise seen on the EEG. In addition they discovered that the extra time the reindeer spent ruminating, the much less they wanted extra relaxation.
Wagner suspects any such multitasking may assist the animals get sufficient relaxation in the course of 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 quick interval of the 12 months when it’s a must 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.