Wild boars, also known as feral pigs (Sus scrofa), are a non-native, invasive species with a widespread distribution across California. They are not indigenous to North America and have established themselves as a permanent fixture in the landscape. Their high reproductive rate and adaptability pose significant management challenges. Wild pigs are confirmed throughout a majority of California’s counties, impacting both natural ecosystems and agricultural operations.
Confirmation and Origin
The wild pig population in California resulted from two distinct historical introductions, creating a hybrid animal. The initial introduction occurred in the 1700s when Spanish settlers brought domestic pigs for livestock. These pigs escaped or were abandoned, establishing the first feral populations in the state.
A second introduction happened in the 1920s in Monterey County, where European wild boars (Sus scrofa) were imported for sport hunting. These wild boars interbred with the existing feral domestic pigs. This hybridization resulted in the resilient, larger, and more aggressive hybrid commonly found today, allowing the species to thrive and spread rapidly across diverse habitats.
Geographic Distribution
Wild pigs are adaptable, and their range extends into 56 of California’s 58 counties, utilizing a variety of habitats. The animals can be found in environments ranging from chaparral and grasslands to woodland and meadow areas. The central regions of the state experience the highest concentration of the population.
Areas like the Central Coast, the Sierra Nevada foothills, and parts of the Central Valley are particularly affected. These pigs prefer habitats that offer dense cover for shelter and are in proximity to water sources, which they require for wallowing and hydration.
Environmental and Agricultural Impact
The feeding and rooting behaviors of wild pigs make them one of the most destructive invasive species in the country. Their characteristic rooting—using their snouts to overturn soil in search of roots, tubers, and invertebrates—disturbs large tracts of land. This action leads to soil erosion, uproots native vegetation, and creates opportunities for invasive plant species to colonize the disturbed ground.
Wild pigs degrade water quality through wallowing, contaminating streams, springs, and reservoirs with sediment and harmful pathogens. They also compete with native wildlife, such as deer and small mammals, for food resources like acorns and other mast crops. The animals threaten biodiversity by preying on the eggs of ground-nesting birds and small native species like the California tiger salamander.
In the agricultural sector, the damage is substantial, with farmers reporting major losses from crop destruction. Wild pigs consume or trample crops and pastures, and their rooting can damage irrigation infrastructure and farm ponds. Furthermore, their presence poses a public health risk, as they are known to carry and spread more than 30 infectious diseases that can contaminate food sources.
Regulation and Control
The California Department of Fish and Wildlife (CDFW) classifies the wild pig as a “game mammal,” dictating that the primary method of population control is regulated hunting. Hunters must possess a valid hunting license and a specific wild pig validation. Unlike many other game species, the hunting season for wild pigs is open all year, and there is no daily or seasonal limit on the number of animals a hunter can take.
While year-round hunting is used to manage the population, it has not been fully effective in controlling overall numbers. Landowners experiencing property damage can pursue other avenues of control through the CDFW’s depredation permit process. These permits allow landowners or their authorized agents to remove nuisance pigs outside of typical hunting regulations, often involving trapping for local control.