Feral

A feral organism is a plant or animal which has changed from being tame or cultivated to being wild.

A feral animal is one which has escaped from a domestic or captive status and is living more or less as a wild animal. Animals which were wild before they escaped from captivity are not regarded as feral. For example, a lion which has escaped from a zoo is not a feral animal. Some common examples of animals with feral populations are goats, cats, and pigs.

Domesticated plants that revert to wild are usually known as escaped, introduced or naturalized rather than feral. However, the changes seen in plants that go wild is similar to those of animals.

Some species go feral easily and successfully. Other species usually do not usually survive in the wild.

The introduction of animals or plants to new areas may break down ecosystems. In some cases it has caused the extinction native species. However, returning lost species to their environment can have the opposite effect, bringing damaged ecosystems back into balance. However, sometimes feral species may control other problem species such as rodents, harmful insects, or aggressive plants.