In this busy vacation season, many people multitask. Arctic reindeer aren’t any exception.
Reindeer can eat and sleep on the similar time, a brand new examine suggests. This timesaving technique, described December 22 in Current Biology, provides to the variety of ingenious methods animals can catch some z’s beneath robust situations (SN: 11/30/23).
Arctic reindeer are fairly busy in the summertime — consuming when the solar shines across the clock and the meals is plentiful. Like different ruminants, reindeer spend a substantial period of time chewing on regurgitated meals, making it smaller and simpler to digest. Finding time to sleep amid all this cud chewing is likely to be robust. But not if the reindeer may sleep whereas they chewed.
To discover out if the reindeer may truly sleep-eat, neuroscientist Melanie Furrer and chronobiologist Sara Meier, together with their colleagues, educated 4 feminine Eurasian tundra reindeer (Rangifer tarandus tarandus) to tolerate a pen and electrodes on shaved patches of pores and skin. The course of concerned some kicks and many lichen treats, “which is like sweet to them,” says Meier, of the University of Zurich.
The researchers had been in search of the mind waves that seem throughout non-REM sleep, a deep, restorative sleep section. These waves appeared when the reindeer had been chewing cud, although the chewing movement itself made it arduous to say whether or not the sign was an identical to that of a daily sleep session. “We couldn’t go into element by trying solely on the mind waves, as a result of we now have this chewing in there that disturbs it a bit,” says Furrer, additionally of the University of Zurich.
Still, different indicators additionally pointed to sleep whereas chewing. The reindeer had been calm whereas chewing, typically with their eyes closed. “They had been in a really relaxed state that resembles the physique place of non-REM sleep,” Furrer says. Ruminating reindeer had been additionally more durable to disturb; rustling from neighboring reindeer was much less more likely to get a glance from a ruminating reindeer. When reindeer are stored awake, they want catch-up restoration sleep. But time spent chewing decreased this time spent in restoration sleep, the researchers discovered.
Together, these strands of proof “convincingly exhibit that reindeer are in a position to sleep whereas ruminating,” says neurobiologist Niels Rattenborg of the Max Planck Institute for Biological Intelligence in Seewiesen, Germany, who was not concerned within the examine.
Unlike fur seals, geese and long-haul flying frigatebirds, the reindeer present indicators of sleeping with either side of their brains whereas chewing (SN: 6/30/16). Figuring out precisely how reindeer pull this off could be attention-grabbing, Rattenborg says. Studying numerous types of sleep would possibly result in insights on sleep strolling in individuals, “a poorly understood and doubtlessly harmful sleep problem,” he says.
Neuroscientist and examine coauthor Gabi Wagner notes that Indigenous reindeer herders have an idea that roughly interprets to “pasture peace.” Reindeer “want time and house to be quiet and to have peace, to ruminate,” says Wagner, of the Norwegian Institute of Bioeconomy Research in Tromsø. “This paper for the primary time reveals that it is a very actual, physiological requirement to have sufficient peace to ruminate undisturbed in an effort to cowl the sleep necessities.”
For now, let’s all be cheered that reindeer can take excellent care of themselves. Some of them is likely to be busy this Christmas Eve.