(CNN)The Sierra Nevada red fox, a rare California species whose population is dramatically dwindling, has been listed as endangered.
The US Fish and Wildlife Service (FWS) announced in a news release Monday that the fox population in Sierra Nevada, which only consists of about 18 to 39 individuals, will receive protection under the Endangered Species Act.
The foxes now live in just California's Sierra Nevada and the southern Cascade Range of Oregon and California. The Sierra Nevada red fox population in the southern Cascade Range will not be listed as endangered, according to the press release.
"Our partners are putting conservation practices into place that will that help minimize forest fragmentation and limit activities that could disturb the dens of these rare foxes," Paul Souza, regional director of the FWS' California - Great Basin region, said in a statement. "Their actions are critical to the recovery of the species."
The Sierra Nevada red fox faces multiple threats, including wildfires, droughts and competition with coyotes, according to the release. Due to "decreases in prey numbers and widespread hybridization with non-native foxes," the species finds itself vulnerable, FWS said.
The Federal Register notice listed five reasons for declaring the species as endangered: a threat to its habitat, over utilization for numerous purposes including commercial and recreational, disease or predation, inadequate regulatory systems, and other natural or manmade factors that threaten the population. The rule is effective beginning September 2, 2021.
The solitary foxes are extremely hard to track down and rarely spotted. When the fox was sighted at Yosemite National Park in 2015, Don Neubacher, the park's superintendent at the time, called the species "one of the most rare and elusive animals in the Sierra Nevada."
According to a fact sheet from the US Forest Service, the Sierra Nevada red fox lives in remote and rugged habitats.
"The Sierra Nevada red fox is specially adapted to its native subalpine habitat, which is characterized by heavy snow, short growing seasons, and a mixture of open and forested areas," the release said. "Despite its name, Sierra Nevada red foxes can be either mostly red, mostly black, or a greyish brown cross phase."
It's not known why the population of this specific species has decreased so drastically. Their bright red fur once made them a popular target for hunting, but that has been ruled out as a factor, says the Forest Service, noting that hunting and trapping them was banned in 1974.