Pet

A domestic animal is an animal belonging to a species which has undergone modifications, by selection, by humans. It is an animal that, raised from generation to generation under human supervision, evolved to form a species, or race, different from the primitive wild form from which it originated.

A domestic species is a species all of whose representatives belong to selected animal populations or are derived from relatives of selected animal populations.

The list of domestic species of animals is limited by ministerial order. Thus, for example, dogs, cats, horses are domestic animals but also pigs, camels, white peacock, koi carp, silkworm, etc.

Wild animal

A wild animal (or non-domestic animal) is an animal belonging to a species which has not undergone modification by selection on the part of man. Any animal not listed in the pet list fixed by ministerial order is a wild animal.

Tamed animal

A tamed animal is not necessarily a pet. A wild animal can be tamed.

Pet

A pet is an animal held or intended to be held by man for his approval. It's not necessarily a pet, or even necessarily a tamed animal.