And half manimal half humans would be.. minamals?
The easiest name to come up is "beast". Maybe "splitter" is fitting too. (his identity is splitted between human and animal)
This link for race names: http://www.fantasynamegenerators.com/species-names.php
Well, it highly depends on what kind of animal it is. However, if you want it to be simple you can always go with "half-breed" ...
Separate names with a comma.