How are you defining "animal?" By actions? By intellegence? By psychology?I don't think humans are animals, all though some seem to act like they are. And I think the main difference is, animal actions seems to be based on instincts, humans can act by reason.
Does someone with a brain injury or dementia cease to be human and become an animal?
"Animal" is almost always used in it's biological sense, defined by specific physical criteria. Do humans not fit the criteria?