Gary Zahm/U.S. Fish and Wildlife
While at Yosemite, look all around you and, perhaps, you’ll find something looking back at you. Chance encounters are likely because Yosemite National Park supports more than 400 species of vertebrates including fish, amphibians, reptiles, birds, and mammals. You might catch the eyes of an acorn woodpecker, a California ground squirrel, a bobcat, or a Western fence lizard. A human connection to animals, perhaps, entices our curiosity to be close to them, in part, by studying them.
The high diversity of species is the result of diverse habitats in Yosemite that are largely intact. The park’s rich habitats range from thick foothill chaparral to conifer forests to expanses of alpine rock. Animals feel at home in each location; the Sierra Nevada red fox, for instance, hunts in open alpine habitat and retreats at night into the forest for safety.
In Yosemite Valley, home to the mule deer and black bear, visitors should watch for species that depend upon meadow habitat. Animals come to feed on the green grasses and use the flowing and standing water found in many meadows. Predators, in turn, are attracted to these areas. The interface between meadow and forest is also favored by many animal species because of the proximity of open areas for foraging, and cover for protection.
U.S. Forest Service
Overall, the park's widespread coniferous forests--with a relatively mild climate and a mixture of plant species--provide a lush habitat for animals to live. Wildlife species typically found include bobcat, gray fox, mountain kingsnake, Gilbert's skink, white-headed woodpecker, brown creeper, spotted owl, and a wide variety of bat species. Large snags are important as bat roosting sites.
At higher elevations, fewer wildlife species tend to be found due, in part, to the lower complexity of the forest. Species likely to be found include golden-mantled ground squirrel, chickaree, marten, Steller's jay, hermit thrush, and northern goshawk. Reptiles are not common but include rubber boa, western fence lizard, and alligator lizard.
Above treeline, the climate becomes harsh with a short growing season. Species such as pika, yellow-bellied marmot, white-tailed hare, Clark's nutcracker, and rosy finch are adapted to these conditions. Sierra Nevada bighorn sheep are found in the Yosemite area only around Tioga Pass, where a small, reintroduced population exists.
Despite the richness of high-quality habitats in Yosemite, approximately 40 species have a special status under California endangered species legislation. Three species--grizzly bear, California red-legged frog, and foothill yellow-legged frog--are believed to be extirpated in the park within recent history. Serious threats to Yosemite's wildlife and the ecosystems they occupy include loss of a natural fire regime, exotic species, air pollution, habitat fragmentation, and climate change. On a more local basis, factors such as the availability of human food and occurrence of road kills negatively affect wildlife species.
“In final analysis, no two species well established in a region occupy precisely the same ecologic space; each has its own peculiar places for foraging, and for securing safety for itself and for its eggs or young. These ultimate units of occurrence are called ‘ecologic niches.’” – Joseph Grinnell and Tracy Irwin Storer, Animal Life in the Yosemite, University of California Press, 1924