Highly recommend trapping in circle of gates. It is completely passive if there is no other members of the same species it transforms into even if it becomes a rex it'll be passive. If you can't do a transformation just wait for it to change back to itself then to another creature tamih effectiveness and % will remain unchanged. It seems to favor turning into.

Paracertherium, Sabertooth, Anky, Procoptodon, Carbonemes, and few other similar creatures. It doesn't seem to turn into flying dinos when wild