Rising temperatures put heat on pikas’ future

Jerry McBride/Durango Herald file photo

Rising temperatures threaten alpine-dwelling pikas by shortening the period available for them to gather food.

When inner tubing on the Animas starts in early June instead of mid-July, it is just one of many signs that summer is hotter than usual.

Folks in Durango, who usually do fine without air conditioning except for a couple of peak weeks, are finding themselves feeling stifled for a longer period of time. As humans struggle to deal with record heat, we have to wonder how changing temperatures are affecting the animal world. One of the species that is most affected by rising temperatures is the tiny alpine-dwelling pika.

Pikas are a close relative of the rabbit and are grey in color, blending in to their rocky alpine environment. Most people don’t see pikas until they give themselves away with their shrill squeaky call. They are very vocal, calling out to each other as they scurry in and out of rock piles. In fact, another name for the pika is “whistling hare.”

When hiking in high elevation, pika signs can be seen by noting their distinctive hay piles. They harvest vegetation from alpine meadows during the short growing season and store it as winter food in mounds beneath boulders.

Pikas have long winter coats to keep warm and start to shed them in late spring and again in early fall. But because of the short warm season at high altitude, the shedding seasons overlap, giving them a scruffy look most of the summer.

Predators of pikas include weasels, martens, coyotes and hawks. But the pika is not often caught by their larger predators because of their ability to escape into rock piles. The real threat for the little 7-ounce pika is the heat.

Rising temperatures threaten pikas by shortening the period available for them to gather food, changing the types of plants in the alpine meadows where they feed, shrinking the size of alpine meadows and reducing insulating snowpack that protects them from cold snaps in the winter.

Most directly, warming also can cause the animals to die from overheating. Because pikas don’t hibernate, they need a very insulating coat of fur. In addition, to handle the extreme alpine winter temperatures, the resting body temperature of a pika is near its lethal maximum. Both of these characteristics make it very intolerant to summer heat. During the hottest parts of the summer, they take refuge in the coolest parts of the talus, or slopes formed by an accumulation of rock debris.

Many pika studies, on the Front Range and locally by the Mountain Studies Institute, are underway to determine the affects of warming temperatures on the pika. It is mostly thought that their survival as a species is tied to their persistence in the alpine ecosystems of the Rocky Mountains.

As the temperatures rise to unbearable levels, Durangoans can at least escape to the Animas River. For the pika, already living at the highest elevation, there really is not much room left for them to go.

sally@durangonaturestudies.org or 382-9244. Sally Shuffield is executive director of Durango Nature Studies.

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