Feral hogs will spread to most parts of the USA, says a new study.

Researchers at the USDA’s National Wildlife Research Center say in a statement: “Without immediate and enhanced efforts to curtail the spread of [feral hogs], we predict that large portions of the USA are in immediate risk of invasion.”

The USDA collected data on America’s wild pig population in 3106 of the 3141 American counties during four time periods, from 1982-1988, 1988-2004, 2004-2009 and 2009-2012. Pigs showed up in 630, 1078, 1180 and 1358 of the counties respectively, mostly in southern and western parts of the US. There are currently five to six million wild pigs across at least 35 states.

The US already spends an annual $US1.5 billion ($1.9 billion) controlling their spread and cleaning up the crops they damage. Humans are their main predators.

Hogs boom in USA