(CNN) It's not every day that a fox sighting makes headlines. But when it's a once-in-a-century sighting of a rare Sierra Nevada red fox, it merits a mention.

Researchers on staff at Yosemite National Park made the find during a five-day trek through the backwoods of the park. The scientists, part of the aptly named Yosemite Carnivore Crew, went to check on motion sensitive cameras. That's when they saw them: two images of the fox, one from December and another in January, trotting through the snow.

Don Neubacher, the park's superintendent, said he's "thrilled" by the news. He called the species "one of the most rare and elusive animals in the Sierra Nevada." It's the first time the fox has been spotted in the park in nearly 100 years.

Indeed, little is known about the fox in part because they're so hard to track down. According to a fact sheet from the U.S. Forest Service, the Sierra Nevada red fox lives in remote and rugged habitats. They're solitary and have a habitat range from California to southern Oregon and western Nevada. It's thought 50 of them may remain, but the fact sheet notes that there could be as few as 15.

It's not known why the population of this specific species has dramatically dwindled. 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.

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