The domestic dog is a subspecies of the gray wolf, a member of the Canidae family of the mammalian order Carnivora. The term "domestic dog" is generally used for both domesticated and feral varieties. The dog was the first domesticated animal and has been the most widely kept working, hunting, and pet animal in human history. The word "dog" can also refer to the male of a canine species, as opposed to the word "bitch" which refers to the female of the species.