A Sierra Nevada red fox is seen in an image provided by the National Park Service at Yosemite National Park, California, U.S., Jan. 29, 2015. Biologists have spotted a Sierra Nevada red fox at Yosemite National Park for the first time – a sighting of one of the rarest mammals in North America, thought to number only 50 on the continent, officials said.
A female gray wolf and two of the three pups are seen in the wilds of Lassen National Forest in northern California, June 29, 2017. Gray wolves, among the first species protected under the Endangered Species Act in 1973, were reintroduced to Yellowstone National Park in 1995. But in other regions of the U.S., gray wolves have dispersed naturally; the population in the lower 48 states now totals about 5,500.
In this undated image taken by a remote camera and provided by the U.S. Fish and Wildlife Service in May 2017, a polar bear and her young cub stand next to a causeway bridge leading to an artificial island oil production platform in the Beaufort Sea in Alaska. The numbers of polar bears in parts of Alaska dropped 40% since the late 1990s and when scientists weighed polar bears recently in certain locations, they were losing 2.9 to 5.5 pounds per day at a time of year when they were supposed to be putting on weight.