The Science of Sustainability

California’s Gray Wolves

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Will gray wolves return to California? Photo: MacNeil Lyons, National Park Service/ U.S. Fish and Wildlife Service – Midwest Region.

When a gray wolf wearing a GPS collar crossed from Oregon into California in December, it was the first wild gray wolf to tread on California soil since the 1920s. Wolves once roamed throughout California, and some people think packs may prowl the state again. It is debatable whether this lone wolf is a sign of things to come, but if wolves return to California, their role in the ecosystem will be different than it was in times past.

Until the early 1900s, gray wolves (Canis lupus) lived throughout much of North America. They were present in California’s Sierra Nevada Mountains, the Coast Range, and the Central Valley, among other locations. Their range was not well documented. Gray wolves are predators; they hunt in packs and eat all kinds of prey, from small rodents on up to Bison. Their main prey items were Tule Elk and Pronghorn, an animal similar to an antelope.

As California’s Central Valley was converted to agricultural fields and pastures, the number of Tule Elk and Pronghorn dwindled. A shrinking supply of wild ungulates (hoofed mammals, such as elk, Pronghorn, and deer) meant that wolves started going after livestock—with major repercussions. Predator control programs led to extinction of the gray wolf in the lower 48 states. In 1924, the last known wolf in California was trapped and killed in Lassen County.

Gray wolves were added to the Endangered Species List in 1974, shortly after the Endangered Species Act was passed. Then, in the mid 1990s, gray wolves from Canada were re-introduced to Idaho and to Yellowstone National Park.

The gray wolves introduced to Idaho expanded their range, and there are now about 1600 wolves in the Northern Rocky Mountains and Pacific Northwest. In Idaho, there are concerns that the local population is growing too large, and the wolves are getting too close to human habitation. Last year, gray wolves were de-listed in certain areas, where it became legal to hunt them. Five wolves were killed via aerial gunning in Idaho.

Studies on the wolves in Yellowstone, conducted by Chris Wilmers, Assistant Professor in the Environmental Studies Department at the University of California Santa Cruz, have found that gray wolves buffer the effects of climate change for other carnivores. Many scavengers, such as bald eagles, coyotes, and black bears, feed on elk carcasses during the winter. After heavy snowfall, elk become exhausted from walking through deep snow and eventually expire. However, winters are becoming shorter as a result of climate change, and there are fewer elk carcasses to be scavenged. After wolves were released in Yellowstone, their hunting activity increased the availability of food for scavengers.

The Gray Wolf that recently crossed into California—named OR7 and re-named “Journey” in a naming contest—split off from his pack in Oregon. Wolves can outgrow their packs and will disperse to find a mate. As the only known wild gray wolf in the state, is highly unlikely that Journey will find a mate. And without a pack to hunt with, this lone wolf will probably need to scavenge for food. Journey probably won’t father California’s future wolf population, but it is possible that other Oregon wolves may follow in his nearly 1000 miles of footsteps.

California has suitable habitat for gray wolves, and has plenty of potential prey. But the state has changed a lot since gray wolves had the run of the place in the 1800s. There is little open space, and the climate is drastically altered; if wolves return, their ecological role will be very different.

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Category: Biodiversity, Biology, Climate, Environment

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Jennifer Skene

About the Author ()

Jennifer Skene develops curriculum on climate change and ocean sciences at the Lawrence Hall of Science and teaches biology and science communication at Mills College and the University of California Berkeley. She has a degree in biology from Brown University and a Ph.D. in Integrative Biology from UC Berkeley. She started working with QUEST in 2008 as an intern. She has written for the Berkeley Science Review and the UC Museum of Paleontology’s Understanding Evolution and Understanding Science websites.