![]() According to the team, this more easily accessible and digestible food source could reduce the amount of time they need to forage and help explain why pika are more abundant in areas with yak, animals normally considered their competitors for food. Individuals living in areas with high densities of domestic yak populations were also observed eating yak feces, which the authors confirmed via analysis of stomach contents for yak DNA. ![]() These data showed the while they don't hibernate, they pika suppress their body temperatures-more so when it is colder. To determine how the pika achieve this reduction, the authors filmed the animals' activities and implanted them with temperature logging devices. ![]() The team of researchers measured daily energy expenditures of two wild study populations of the pika and found that energy expenditures are about 30 percent lower in winter. Moreover, in winter the grass becomes extremely dry and unpalatable. The Qinghai-Tibetan plateau averaging around 4000m in elevation combines extremely low temperatures with low oxygen partial pressure to provide a uniquely challenging environment in winter. Their work, published today in the journal Proceedings of the National Academy of Sciences, shows that pika suppress their energy demands and exploit an unusual food source-eating the feces of their competitor the yak. This is also economically important for indigenous Tibetan yak herders because pika are considered an agricultural pest that compete with domestic yak for food. Pika cannot hibernate and so their survival strategies are of interest: particularly in the context of how these might be impacted by future climate change.
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