Firefox is another name for the Red Panda and is the animal Mozilla named their well known browser for. I guess they didn't put it in their logo because they aren't as recognizable as foxes are. The Red Panda is not a fox or a bear (like the Giant Panda), but is more closely related to skunks, weasels and raccoons. It is in it's own family, Ailuridae.
Red Panda (Ailurus fulgens)
. Together we are =SalsolaStock