Wild pigs did not exist in California until the early 1700s, but they now are found in at least 56 of the state's 58 counties.
Hunters like them, but they are a headache to environmental and open space managers, and to some homeowners.
Sows can produce two litters per year, of up to six piglets per litter.
The pigs till up plants, lawns and soil in search of roots, tubers, bugs and other food items.
Weighing up to 300 pounds, the animals with tusks are called animal rototillers. They compete with native wildlife for food and habitat, and eat wild bird eggs.
Wild pigs are hybrids; Spanish and Russian explorers in the 1700s brought domestic pigs to this country and they escaped into the wild. In the 1920s, hunters brought wild boars from Europe to California and released them.
The two pig stocks interbred, producing a wild boar/feral pig mix.
State wildlife managers advise homeowners with wild pig problems to pick up fruit and remove food sources. Fencing also is recommended, but some homeowners are reluctant for aesthetic reasons to fence off their front yards.
In areas where hunting is allowed, state wildlife managers say hunting is a sound way to thin wild pig populations.
According to state officials, hunters bagged some 3,574 wild pigs in California during the 12 months of the 2010-2011 hunting season.
Only 12 percent of the pig hunters with state hunting tags killed pigs, showing that wild pigs are not easily had prey.
During that same hunting season, hunters killed 114 wild pigs in Santa Clara County, 19 in Contra Costa and 16 in Alameda County. Kern County was tops in the state with 591 wild pigs killed by hunters, according to figures from the California Department of Fish and Wildlife.
Wild pigs are primarily nocturnal in areas with hunting but active in the daytime in areas without hunting.
Wildlife managers advise people to give wild pigs a wide berth and not attempt to corner the animals, which can become very aggressive.
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff