do you refer to animals as who or what? In English we refer to animals as it how do you do it in french

Quite often there are different nouns for male and female animals. For instance:

un chat - une chatte
un chien - une chienne
un oiseau - une oiselle
un cheval - une jument
un taureau - une vache
un coq - une poule
un merle - une merlette
un lapin - une lapine

If you're unsure of the gender you use the male version, normally.

Some animal names only come in a male of female version, for example: la souris. Here the grammatical gender wins:

J'ai une souris blanche, elle s'appelle Auguste, c'est un mâle.
J'ai un hamster noir, il s'appelle Louise, c'est une femelle.

I would say “qui “ (who) for animals: e.g. J’aI un chat qui s’appelle Herbie

Just as a heads up, it is grammatically correct to use “her” or “him” for animals in English, and for many people using “it” for an animal is insulting or just plain incorrect. “It” refers to something inanimate and animals are certainly not that.