Common name: Feral pig
Scientific name: Sus scrofa
Description: The feral pig has coarse hair and a solid build. A male pig can weigh up to 175kg, a female 110kg. If the pig is a colour apart from black, it is most likely a cross-breed with domestic stock. The feral pig has smaller and narrower hindquarters than domestic breeds. Its coarse hair around its neck bristles when the animal is stressed.
Habitat and distribution of the feral pig
European settlers introduced the pig for food. Often allowed to roam free, it was not long before this animal had established populations in the wild.
Feral pigs are found in most habitats, except for dry inland areas. This is because the pig needs a reliable supply of food, water and shelter to survive. Pig group sizes can vary depending on environmental conditions and control measures. In north Queensland, groups can number more than 60!
The feral pig is now found in every state of Australia except Tasmania, causing widespread damage to natural ecosystems.
Life history and behaviour of the feral pig
Feral pigs breed throughout the year in favourable conditions with breeding peaking between May to October. Females can breed from seven months of age and have one or two litters a year of four to six piglets. The female builds a nest of grass and tunnels inside to give birth.
A large number of piglets can die, depending on food and weather. However, this doesn't affect numbers in the long term, as pigs are sometimes able to double their population in one year!
Pigs are opportunistic feeders. They eat mostly grass but they will also munch on fruit, roots, beetles, reptiles, crocodile eggs, young rabbits and other small animals. They need to drink daily especially in hot weather.
Environmental impact of the feral pig
It is one of Australia's most destructive environmental and agricultural pests. The feral pig damages natural habitats through wallowing and rooting for food in watercourses and swamps. It does this to keep cool in hot weather, but in the process it damages water bodies and destroys native vegetation. Feral pigs are known to eat some threatened plants and destroy their habitat including orchids of north Queensland. Food and nesting sites for native animals are also damaged by pigs. In Queensland, pig damage can be seen in many national parks.
An aggressive competitor for food with native animals in tropical rainforests, the pig is also an agricultural pest. It competes with domestic livestock for food and damages crops such as cereal, sugarcane and corn. It can also damage fences.
Feral pigs are known to eat young lambs, removing up to 40 percent of livestock in some areas. This costs the sheep industry millions of dollars a year.
In many parts of the country, pigs are carriers of diseases such as Murray Valley encephalitis and Ross River fever. If any exotic diseases entered Australia, the pig could cause severe problems as an infectious reservoir or transmitter of disease.
Pigs can be dangerous animals! If you encounter one in the bush, stay well back.
How can feral pigs be controlled
Shooting, mustering, trapping and poisoning are used to control feral pigs. Unfortunately, feral pigs can recover from control techniques quickly because of their high reproductive rate. Some people's activities are also making things worse. Some hunters have even deliberately released piglets and young pigs into scrub in rural areas! This has not helped control efforts and pig distribution has increased rapidly since the 1970s.
Research is currently determining best practice management and control techniques which will help to get rid of this destructive pest.
Feral pigs are used for their meat with exports to European countries. Landholders often leave pig traps permanently around signs of pig activity.