There are giraffes aplenty, herds of antelope too, and wild pigs, monkeys, jackals and brilliantly coloured birds.

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Louisiana farmers are using drones to hunt invasive wild pigs that carry diseases and spread noxious weeds.

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Their intelligence, in combination with their ability to mate year-round, is what has enabled wild pigs to evade capture and take over prairies, mountain valleys and rugged deserts from Canada to Mexico.

NPR: $1M Pilot Project Aims To Take Out Feral Pigs

On the Big Island, where people use dogs for hunting wild pigs, many residents have at least five and some as many 30 dogs, says Debbie Crazatta, founder of the Kohala Animal Relocation and Education Service, which helps find homes for stray dogs.

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Generations in the wild, the pigs have evolved into "survivors, " willing to eat just about anything and capable of traversing some of the most rugged territory.

NPR: $1M Pilot Project Aims To Take Out Feral Pigs

Humans have introduced dozens of species into Australia - including wild horses, pigs, goats, dogs, cats, rabbits and foxes - and these have now become a major problem for the ecosystem.

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GARCIA-NAVARRO: Galapagos is named after these reptiles, but their populations have been hurt in the wild by rats, pigs and goats.

NPR: Common Intruders Threaten Galapagos Species

Imagine that we only ate wild cows, or chicken, or pigs.

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As wild migratory birds will sometimes visit farms and as domestic flocks of ducks or chickens often live alongside pigs, especially in developing countries, this is quite feasible.

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