Feral pigs directly affect agriculture by feeding on crops and livestock, causing damage by rooting and trampling, and by harbouring and spreading diseases and parasites. Damage tends to be local but the overall costs to agricultural production in Australia were conservatively estimated in 1996 at around $100 million per year.
Pigs are not native to Australia. Domestic pigs were often allowed to range freely to forage for food in the bush and some inevitably became feral, living and breeding in the wild. Accidental or deliberate introductions of domestic pigs into the wild continue even today.