The class for a gray wolf is Mammalia.
Here is a breakdown of the classification:
* Kingdom: Animalia (Animals)
* Phylum: Chordata (Chordates)
* Class: Mammalia (Mammals)
* Order: Carnivora (Carnivores)
* Family: Canidae (Canids)
* Genus: Canis
* Species: Canis lupus