American pikas are small, mountain-dwelling lagomorphs that look like a cross between their rabbit cousins and rodents such as guinea pigs or hamsters.
They’re common throughout the Rocky Mountains in the USA and southern Canada up to elevations over 4,000 metres. They specialise in inhabiting broken rocky habitats known as talus and are not considered to be threatened with extinction.
But new research published in the journal Arctic Antarctic and Alpine Research suggests they could nevertheless be in trouble. Chris Ray, an ecologist at the University of Colorado Boulder, compared trapping data from the 1980s at a site just outside Rocky Mountain National Park in Colorado with records from the 2020s, and found that the proportions of juveniles being caught had halved in that time.
It suggests that pikas are having fewer young or that they aren’t migrating in to take the place of the older generation.
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So what’s going on? “Pikas are a cold-adapted species which can’t sweat or pant, so the only way to get rid of heat is to get into a cold place and let it dissipate,” says Ray.
But, for young pikas, there’s a problem. Before they reach maturity, many of them must leave the area where they are born and find their own territory, and this involves moving over south-facing landscapes and lower elevations where they are confronted with increasing temperatures as a result of climate change.
It’s not exactly clear what impact this is having. “My own hypothesis is that it probably doesn’t kill them outright, it simply stresses them,” Ray says. “The more stressed an animal is, the more likely it is to be killed by something else.”
While Ray emphasises there are still “millions of pikas out there”, her research suggests global warming could lead to pika populations dying out because there is not enough recruitment.
That matters for a number of reasons, she explains. First, they don’t hibernate, so are important prey animals during the winter for predators such as raptors, weasels, foxes and coyotes.
Second, they are an indicator species – canaries in the coal mine – for what’s happening to the talus habitat. Rising temperatures could lead to loss of permafrost and seasonal snow that are important sources of meltwater for reservoirs.
And third, they just matter. Pikas feed on flowers and grasses in meadows adjacent to the talus where they live, and they return from foraging trips with their mouths full of flowers and grasses which they stash under a rock as food for the winter.
“It’s a whole bouquet, and that’s another reason we don’t want to lose them,” says Ray. “They’re way too much fun. If they disappear, our experience is diminished.”
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Top image: American pika. Credit: Rachel Ames
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