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Located high above the western tree lines, from British Columbia to New Mexico, live a small species of rabbits called the American Pika. While these diminutive critters, otherwise known as the Little Chief Hare, may be cute and cuddly, they also have a much more serious and important role. They are among the best early indicators of climate change. Pika cannot survive longer than an hour in temperatures exceeding 75 degrees Fahrenheit, and their disappearance from their typical colonies has convinced scientists that climate change is happening much faster than expected in North America.

It isn’t only excessive summer heat that is a problem for pikas; they are also sensitive to the winter cold. To protect itself from frigid temperatures, a pika uses snow for insulation and protection from the occasional below-zero weather—akin to the Eskimos and their igloos. With warmer temperatures, the amount of snowfall has decreased, causing many pikas to die due to insufficient protection from the cold. This has led to huge decreases in pika colony populations.

Faced with thinning colonies, many other animals would immediately re-colonize. However, pikas cannot easily emigrate to a site on another mountain due to high temperature in the valleys, long stretches of impassable highway in the Great Basin region and wide-open spaces that make them easy targets for predators. Hemmed in by these barriers, the decimated pika colonies remain separate and vulnerable. To escape warmer temperatures, they travel upward toward the peak of the mountain, despite less food and harsher winters.

While pikas are feeling the most direct effects of climate change, their disappearance would affect a very large part of the ecosystem, starting with the animals that prey on them. Although eagles and hawks occasionally eat the pika, their main predator is the leaping mountain weasel. With its flexible, tube-like body, the weasel can easily follow the pika into small crevices and tunnels. While pikas are not the main diet of weasels, the disappearance of this significant food source will still drastically decrease the weasel population, which is already in danger due to habitat destruction and pollution.

It’s not just the predators that are affected by the extinction of pikas, but the habitat itself. Pikas are considered ecosystem engineers (organisms that create or modify their environment). Their extensive haying activities have the beneficial effect of modulating nutrient availability to plants. As food is difficult to obtain during the winter, pikas collect a variety of plants and flowers, and dry them in the sun. This food is then gathered and stored for the winter. Scientists observed that the soil beneath the hay piles were rich in nitrogen, the main nutrient that the talus and scree soil lacks. Should pikas become extinct, the plant life that had once flourished would diminish as the necessary supplements vanished. This would lead to a decrease in all animal life on the rocky talus, as less plant life would mean less food available for herbivorous animals; fewer herbivores would mean less food for the carnivores/predators.

The higher that temperatures rise, the less pikas there are, until eventually they will completely die out. Any ecosystem is greatly affected by the extinction of an entire species, no less so on the rugged terrain of the rock talus. The disappearance of the pika would mark a huge shift in animal population and diversity on the mountaintops.

But pikas also have great significance beyond their own environs. They serve as the “canary in the coalmine” for climate change, which will have far-reaching and dire consequences for many species, including man. While there are still deniers of global warming, pikas are one proof. By keeping an eye on their population, we can see how slowly or rapidly global warming is occurring in North America. Hopefully, this will spur us to action before it is too late for the pika—and maybe, for us.

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