You might describe your own cat as gray, but in the world of breeding and
cat shows, there are no gray cats, only blue ones. (As far as that goes, no
human or cat is naturally “red,” yet when we refer to a cat or person having “red” hair, people know exactly what we mean.) Likewise ginger is applied to orangey-coated cats, even though real ginger (the spice, that is) is brown, not orange.