Wild pigs were introduced to Australia with the First Fleet, and now occupy around 45 percent of the country, mainly in Queensland and New South Wales. 

Feral pigs in Australia descend from domestic pigs, but have evolved to be better suited to living in the wild. The Pest Smart website, which is operated by the  Centre for Invasive Species Solutions gives the following description for wild pigs.

"They tend to have sparse, coarse hair on lean and muscular frames, well-developed necks and shoulders that taper to short hindquarters. Colouration is predominantly black, rust-coloured or black and white spotted. Females are usually smaller and weigh less (50–60 kg) than males (80–100 kg). Pigs have keen senses of smell and taste and good hearing, but their eyesight is generally considered to be poor.

Feral pigs are highly social and intelligent animals that naturally form groups, known as 'mobs', or 'sounders' in the United States. These groups are usually less than 12 individuals, although they can be as large as 400 if conditions are right¹. Feral pigs are most active from late afternoon to early morning."

Pig Dogging

The practice of "pig dogging" involves hunters releasing aggressively trained dogs to track, chase and maul live pigs, keeping them pinned down until the hunters are able to catch up and finish them off with a knife. Today there are up to 24 million feral pigs across Australia.

Dogs will often be injured by the teeth and tusks of pigs, and hunters have been known to use staple guns to close wounds on their dogs. Multiple investigations have shown pig doggers tormenting pigs by getting their dogs to repeatedly attack them.

Despite wild pigs being declared a pest animal, it's not uncommon for the hunters to release young piglets into national parks so that they can return later to hunt them. It is estimated that feral pigs cause $100 million of loss to the agriculture industry each year, mainly through predation on lambs and competition over grazing lands.

References

1. Long J (2003). Introduced Mammals of the World: their History Distribution and Influence. CSIRO Publishing, Melbourne.