Feral Children

Definition: human children that live isolated from human contact having no (or little) experience of human care, speech, or what we would regard as normal social interaction. These children are often raised by animals having been abandoned at a young age or run away due to child abuse.

There have been over a hundred cases of children being brought up in the wild.

You can read more about them here, some of the stories are really fascinating:

http://listverse.com/2008/03/07/10-modern-cases-of-feral-children/