Yosemite is home to 90 species of mammals, which include, but are not limited to, bats, rodents, carnivores, and hoofed animals. The Virginia opossum is the lone marsupial. The Virginia opossum and the beaver are not native to the area. The two hoofed animals include the big horn sheep and mule deer. Rodents are abundant throughout the valley and in the higher elevations. They include several varieties of hares, including the white-tailed hare. Also included are the chickaree, pika, marten and the golden-mantled ground squirrel. Some of the larger creatures would be the yellow-bellied marmot, weasel, porcupine, raccoon and skunk.

Coyotes are found quite often roaming on the valley floor, as are the black bear and gray fox. Mountain lions and bobcats are more elusive but are also found throughout Yosemite. Many of Yosemite’s mammals, like mule deer and gray squirrels, are fairly common and can be readily seen every day. Others, like the wolverine and Sierra Nevada red fox, are extremely rare and might be sighted only once a decade.

Although often overlooked because of their nocturnal habits, bats represent a large proportion of the park’s mammalian fauna. The mobility of these remarkable flying mammals enables them to occupy a wide range of habitats. They are found from the lowest elevations in the park to over 10,000 feet. They roost in rock crevices and caves, under loose bark and bridges, in attics and tree cavities. North America’s largest bat species, the western mastiff, is a Yosemite resident, as is the spotted bat with its huge ears and vivid white spots. These are the only two species in Yosemite whose echolocation calls are audible to the human ear.

Of the 90 mammal species on the park’s fauna list, 17 are considered "special status" by either the federal or California state government due to declining population numbers or a lack of information about their distribution and abundance. Currently, Sierra Nevada bighorn sheep are the only park mammal on the U.S. Fish and Wildlife Service Endangered Species list.