Normal animals tend to be few and far between in miniatures. There are lines of anthropomorphic animals, and all sorts of chimera- mostly of predators.
Most animal minis are either animal companions or mounts. Arena Rex has a neat opportunity- their setting has quite a few plain old animals in it (from my theatre history, animals were features in the colosseum more often than gladiators fighting one another).
The animals of Arena Rex are just as well sculpted as the humans and monsters of the line- they're absolutely beautiful minis and take to paint brilliantly.