|Feral pigs are also known as feral hogs and razorbacks.|
Pigs were often purposefully introduced to areas for use as a food source, either as semi-domestic animals or for use as game. As such, it was common for explorers to leave some behind after they discovered a new location. Sometimes pigs would escape, but in almost all cases the ancestors of the feral pigs seen today were purposefully released. Part of this is thanks to some of the methods used to feed the pigs: namely letting them run free and having them find their own food.
When it comes to managing pig populations, there are numerous methods used. Poisoning is one of the most common as it is the most cost effective. However, as with any poisoning, there is a high risk of poisoning species other than the one being targeted. Also, pigs are known to vomit up certain poisons, making them less likely to actually kill the pig. Trapping is also done, after which the pigs will generally be destroyed rather than relocated. Since they are such mobile animals, it's unlikely simply moving the pig will be helpful. Hunting is also quite common, with various methods being used. Hunting pigs with dogs is one of the most commonly used methods.
Despite their extremely destructive habits, pigs do have their uses. Aside from being a source of food, they were once traded for money or goods. They can help control larvae of some damaging plant parasites. They were also once used to clear and aerate soil for gardens.
Feral pigs are on the list of 100 World's Worst Invasives at #91.
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