You often hear them before you see them. The American Pika is related to rabbits and hares. But they have round ears and no visible tail. Small enough to fit in your hand they blend in with their rocky surroundings and might dart unnoticed if not for their territorial high-pitched cries. A sound some say will fall increasingly silent as climate change makes it tougher for pikas to survive.

Pikas are extremely sensitive to heat and cannot tolerate high body temperatures. They typically seek out cooler high elevation habitat, rarely living below 8,000 feet in the Southwest. As temperatures warm as projected by climate scientists, pikas can be pushed higher and higher until they can’t go any higher to beat the heat. Already they are disappearing from some slopes they once occupied. And there’s another twist.

“The Irony is that pika are vulnerable to potentially freezing to death due to climate change,” said Chris Ray of the University of Colorado Boulder.

“Snow pack potentially protects pikas from sub-zero temperatures and as they loose the snow pack pikas are potentially exposed to freezing over the winter.”

While other animals either hibernate or migrate in order to deal with the cold pikas don’t do either. They will be active throughout the winter and use a series of tunnels under the snow. As the snow pack diminishes over time pikas will eventually find themselves without shelter. And thus vulnerable they are at risk of extinction.