Baboons are animals that are native to Earth. The baboons in After Earth are shown to be aggressive, possibly more so than their ancestor, probably due to humans. They are native to the earth's forests.
(Note: sorry, I couldn't retrieve any more information about this animal from this site: http://speculativeevolution.wikia.com/wiki/Baboon_(After_Earth) because it was deleted as part of candidates for deletion for no reason. Somebody help expand this article)