Feral
Some common examples of animals with feral populations are horses, dogs, goats, cats, rabbits, camels, and pigs.
Feral cats, especially if left to proliferate, are frequently considered to be pests in both rural and urban areas, and may be blamed for devastating the bird, reptile, and mammal populations.
Both goats and sheep were sometimes intentionally released and allowed to go feral on island waypoints frequented by mariners, to serve as a ready food source.
A substantial population of feral dromedaries, descended from pack animals that escaped in the 19th and early 20th centuries, thrives in the Australian interior today.
Most free roaming cattle, however untamed, are generally too valuable not to be eventually rounded up and recovered in closely settled regions.
[9] While the horse was originally indigenous to North America, the wild ancestor died out at the end of the last ice age.
The pig has established feral populations worldwide, including in Australia, New Zealand, the United States, New Guinea and the Pacific Islands.
[citation needed] Many European wild boar populations are also partially descended from escaped domestic pigs and are thus feral animals within the native range of the ancestral species.
[citation needed] Rock doves were formerly kept for their meat or more commonly as racing animals and have established feral populations in cities worldwide.
[11] A feral population can have a significant impact on an ecosystem by predation on vulnerable plants or animals, or by competition with indigenous species.
[13] Researches in Scotland have remarked on a similar phenomenon of the genetic mixing of feral domestic cats and their wild counterparts.
[14] Feral animals compete with domestic livestock, and may degrade fences, water sources, and vegetation (by overgrazing or introducing seeds of invasive plants).
Although hotly disputed, some cite as an example the competition between feral horses and cattle in the western United States.
Prior to the Wild and Free-Roaming Horses and Burros Act of 1971, American mustangs were routinely captured and sold for horsemeat.
At certain times, animals were sometimes deliberately left to go feral, typically on islands,[citation needed] in order to be later recovered for profit or food use for travellers (particularly sailors) at the end of a few years.
The Romanian government is considering the protection of the feral horses and transforming them into a tourist attraction, after it first approved the killing of the entire population.
