4.5: The Fauna of California

The fauna of the State of California may be the most diverse in the United States of America. Of the lower 48 conterminous states. California also has the greatest diversity in climate, terrain, and geology in general. The state's six life zones are the lower Sonoran (desert); upper Sonoran (foothill regions and some coastal lands); transition (coastal areas and moist northeastern counties); and the Canadian, Hudsonian, and Arctic zones, comprising California's highest elevations. California’s diverse geography gives rise to dozens of different ecosystems, each of which has its own unique native plants and animals. California is a huge state, the 3rd largest in the U.S., and can range broadly in habitat type.

Earth scientists typically divide California into eleven distinct geomorphic provinces with clearly defined boundaries. They are, from north to south, the Klamath Mountains, the Cascade Range, the Modoc Plateau, the Basin and Range, the Coast Ranges, the Central Valley, the Sierra Nevada, the Transverse Ranges, the Mojave Desert, the Peninsular Ranges, and the Colorado Desert. Here, the Los Angeles Basin, the Channel Islands, and the Pacific Ocean are treated as distinct regions.

Common animals that live throughout all the state, and its coasts, include raccoons, weasels, otters, beavers, hawks, lizards, owls, coyotes, skunks, snakes, cougars, black bears, deer, squirrels, and whales. As of 2024, there are 685 bird species on the official California checklist but the California Birds Records Committee, ten of which are introduced species which are not native to the state. The California quail, the official state bird, has a breeding habit of mainly shrubby areas and open woodland. Another bird which winters in California is the American white pelican, which is a large seabird, with a wingspan reaching up to 110 inches (280 cm).

Venomous spiders in California include Arizona recluse, Baja recluse, Chilean recluse, desert recluse, Martha’s recluse, Russell’s recluse, brown widow, and western black widow.

Northern California

The forests in northern parts of California have an abundant fauna, which includes for instance the black-tailed deer, black bear, gray fox, North American cougar, bobcat, and Roosevelt elk. Garter snakes and rattlesnakes are common, as are such amphibians as the mudpuppy and redwood salamander. The kingfisher, chickadee, towhee, and hummingbird represent the bird life of this region. There are an estimated 3,487 wild horses in Northern California as of 2024, according to the Bureau of Land Management. Gray wolves began repopulating California in 2011 as they entered Lassen, Siskiyou, and Plumas Counties from the Cascade Range of Oregon.

Case Study - Sierra Nevada

Mammals of the Canadian zone include the snowshoe hare, mountain chickadee, and several species of chipmunk. Conspicuous birds include the blue-fronted jay, hermit thrush, American dipper, and Townsend's solitaire. Birds become scarcer as one ascends to the Hudsonian zone, and the wolverine is now regarded as rare. The only bird native to the high Arctic region is the gray-crowned rosy finch, but others often visit, including the Anna's hummingbird and Clark's nutcracker.

Principal mammals of this region are also visitors from other zones; the Sierra coney and white-tailed jackrabbit make their homes here. The bighorn sheep also live in this mountainous terrain; the bighorn sheep was listed as endangered by the US Fish and Wildlife Service. Some animals in the Yosemite Valley include bobcats, mountain lions, ring-tailed cats, the Steller's jay, California ground squirrels and the American black bear.

Southern California

Southern California constitutes one of the more varied collections of geologic, topographic, and natural ecosystem landscapes in a diversity outnumbering other major regions in the country. The region spans from Pacific Channel Islands, shorelines, beaches, and coastal plains, through the Transverse and Peninsular Ranges with their peaks, into the large and small interior valleys, to the vast deserts of California.

Several varieties of rattlesnakes are indigenous to the region. While only the Pacific Northwest rattler makes its home in Northern California, almost a dozen rattlesnakes make their home in the deserts of Southern California, including the western diamondback and the Mojave rattlesnake. Birds in the region include the Anna's hummingbird, acorn woodpecker, northern flicker, California towhee, California vulture, red-tailed hawk and many more.

Case Study - Mojave Desert

The Mojave Desert appears to have little in the way of wildlife but has large, diverse populations. The extremely warm desert environment has animals that have adapted to their environment with each filling an important niche in the desert ecosystem. Animals in the Mojave Desert include the Mohave rattlesnake, desert tortoise, glossy snake, common side-blotched lizard, California kingsnake, giant hairy scorpion, stripe tailed scorpion and the desert iguana. One of the more iconic ‘trees’ of the region are the Joshua trees. Joshua trees are succulents, a type of plant known for storing water in their leaves or stems. Despite their tree-like appearance with a single trunk and branches, they belong to the yucca family. The story behind their name is quite interesting. Legend has it that 19^th-century Mormon settlers, traversing the harsh desert, saw the tree's outstretched limbs resembling a biblical figure, Joshua, raising his arms in prayer. This association led to the name "Joshua tree."

Coastal California

Along the coast of California is the California sea lion, which can grow up to seven feet long and can be found in shallow ocean water, near beaches, and among rocks. In the open ocean is the northern elephant seal, which grows up to a massive 14 feet (4.3 meters) and has a population of just over 150,000. The California ocean is home to six species of seals: Guadalupe fur seal, northern fur seal, northern sea lion, California sea lion, northern elephant seal and harbor seal.

California waters are also home to eleven species of dolphins, including the short-beaked common dolphin and the Pacific white-sided dolphin. A dozen species of whales live in California, including the killer whale and the gray whale. At least 34 species of shark have been recorded off the California Coast, including the great white shark and tiger shark.

Case Study - Channel Islands

More than 2000 species of plants and animals can be found within the Channel Islands National Park, which consists of five out of the eight islands that compromise the California Channel Islands. Three mammals are endemic to the archipelago: The Channel Islands fox, the deer mouse and the Channel Islands spotted skunk. Introduced mammal species include feral pigs, cats, rats, deer, cattle, the Santa Cruz sheep, and the Catalina Island bison herd.

Other mammals include the harvest mouse, the ground squirrel, and the ornate shrew. Other animals in the islands include island fence lizard, island scrub jay, harbor seal, California sea lion, island night lizard, barn owl, bald eagles, American kestrel, horned lark and meadowlark and California brown pelican. One hundred and forty-five of these species are unique to the islands and found nowhere else in the world. Marine life ranges from microscopic plankton to the endangered blue whale, the largest animal ever to live on earth. The oceans surrounding the islands have a rich marine life; species include orcas, swellshark, bat ray, California moray, great white shark, and sea lions.