There’s an elusive fox roaming the southern Sierra Nevada, and experts are trying to learn more about its behavior and breeding success by analyzing one of the few traces of its presence — poop.

Living in areas above 9,000 feet in elevation, the fox is smaller than most, has fuzzy paws, and a thick fur coat–all adaptations to help it survive the heavy winter snows and challenging alpine conditions. Its fur can range in color from red to black to grayish-brown.

Recently proposed to be listed as an endangered species by the U.S. Fish and Wildlife Service, the southern population of the Sierra Nevada red fox is estimated to consist of fewer than 50 individuals. Recent hybridization with non-native red foxes that escaped from fur farms and other alpine foxes that traveled from Nevada or the Rocky Mountains has put this subspecies at-risk of going extinct.

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