"It really paints a bigger picture as to what could be happening in Yosemite that makes it beneficial for fishers and alternatively, what's happening in where they used to reside that could also be forcing them out,” said David Green of the Oregon State University Institute for Natural Resources.

Scientists also found the long-tailed creatures' scat by searching the wilderness with scat-detecting dog teams. The project is a partnership between Yosemite National Park, the U.S. Forest Service, Rogue Detection Dog Teams, the University of California and Oregon State University.

This winter, Yosemite biologists confirmed that at least one fisher continues to live in forested habitat north of the Merced River. This elusive member of the weasel family was first spotted in the area in 2017, extending their range further north than previously thought. pic.twitter.com/G0Jsqe870s

— Yosemite National Park (@YosemiteNPS) February 23, 2020

The footage and scat samples show there's at least one, but possibly up to six, living north of the Merced River in Yosemite. The last time a fisher was seen here was in 2017. That was the first sighting there in around a century, but biologists lost track of the animal when its tracking collar failed. Four orphaned fisher kits were released north of the Merced River in 2015 as part of an effort to reintroduce fishers in this area.

Happy World Wildlife Day!!
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Biologists were thrilled when, last fall, this wildlife camera footage revealed the first documented sighting of a Pacific fisher north of the Merced River in Yosemite in nearly 100 years.#WorldWildlifeDaypic.twitter.com/VpCAPfiOat

— Yosemite National Park (@YosemiteNPS) March 4, 2018

Populations of the porcupine-eating animals dwindled because of the fur trade and logging during the 1800s. California banned trapping fishers in the 1940s, but according to Yosemite National Park they’ve continued to decline due to “habitat loss from logging, development, and severe forest fires. More recently, prolonged drought conditions and bark beetle infestations have led to increased loss of mature forest stands” they rely on.

Now there are only two native populations living in California, one on the Oregon border and one in the southern Sierra, which is being considered for listing as threatened under the federal Endangered Species Act.

“This detection has actually brought up more questions than answers,” said Green. “It could be because their previous habitat is no longer suitable or that this area is now suitable for fishers even though we previously didn't think it was.”

Green's talking about things like drought and wildfires. He says if analysis of the scat shows the fisher is a female it would increase the significance of the study.

“It’s still most likely to be from a male — male fishers can disperse large distances,” said Green. “But if the scat turns out to be from a female fisher, then this observation becomes even more meaningful. It could mean that reproduction is occurring here, and that fishers might be expanding their range.”