Life isn’t easy on the Tibetan plateau, 16,400 feet (5,000 meters) above sea level. Food is generally scarce and resources are spread thin, but when wintertime comes, things get very difficult.
Many creatures hibernate or move to warmer plains. But for the plateau pika, neither of these is an option. So how exactly do they get through the winter?
For researchers studying them, it has been a mystery. But a 13-year study may finally answer that question. According to the study, the pikas slow down their metabolism and sometimes, even turn to eating yak poop.
The plateau pika is a vital creature for the Tibetan plateau. Through burrowing, they increase plant richness, soil quality and create rich microhabitats not just for themselves, but also for small birds and reptiles who take advantage of their work.
But they don’t get much help for their work. Creatures like foxes, owls, and falcons routinely hunt them and to make matters even worse, during the winter, the pikas have to withstand temperatures down to minus 22 degrees Fahrenheit (minus 30 degrees Celsius). According to the new study, pikas regularly brave the cold and go foraging to survive the winter.
John Speakman, a biology professor at the University of Aberdeen in Scotland and the Chinese Academy of Sciences in China lead the new study. Along with his colleagues, he wanted to figure out just what the pikas do during the winter.
“While we know much about hibernation and migration as survival strategies, the responses of nonhibernating, nonmigrating species are more opaque, yet how these animals survive such periods is important to understand their potential susceptibility to climate change,” the study reads.
So Speakman used data from cameras and found that pikas were indeed going out during the winter. The researchers then wanted to figure out what the pikas were doing with their metabolism — food is less abundant during the winter, so they must have been reducing their energy expenditure somehow.
They implanted 27 animals with temperature sensors and calculated the daily energy expenditure of 156 individuals. Turns out, while many non-hibernating animals keep warm by using more energy, pikas do the opposite: they slow down their metabolism, cool their bodies a couple of degrees overnight, and just brave the cold with what they have.
But then, researchers made another unexpected observation: at sites with yaks, there were more pikas, but the pikas were less active. Researchers struggled to figure out what was going on, until they found a “half-eaten yak turd” in one of the burrows.
It’s not that uncommon for animals to eat their own feces. Creatures like rabbits and even pikas have been found to be doing it sometimes because it helps them absorb nutrients they couldn’t initially digest. Eating the poop of other species, however, is less common, as it can cause sickness. But on the other hand, yak poop seems to be an abundant and easily available meal that reduces the time the pikas need to spend on the surface.
Based on camera observations and analysis, it seems that the behavior is widespread and could be an essential part of what enables pikas to survive the harsh Tibetan winters.
“Pikas supplement their food intake at these sites by eating yak feces, demonstrated by direct observation, identification of yak DNA in pika stomach contents, and greater convergence in the yak/pika microbiotas in winter,” the study concludes.
Plateau pikas are currently considered threatened, and their populations have recently been dropping, mostly due to aggressive poisoning campaigns by the Chinese population, which see pikas as competing for the same type of food as their livestock. Livestock herders poison pikas by the millions.
It’s not clear if other pikas engage in a similar type of behavior, but the study has shaken up conventional thinking about what strategy this type of animal employs for survival during rough times. Future research will further explore what advantages and disadvantages this approach has.
The study was published in PNAS.
