A Gamma Wolf is created when a "True Alpha" bites a human. Since this only happens once in a hundred years, Gamma wolves only exist Once in a hundred years.
In The PackEdit
Gamma: usually one, third in command and a part of the inner council. These werewolves fill a variety of roles, depending on the individual chosen for them. They may have been chosen because their advice is sought and respected, or because they are capable of helping maintain order within the pack and leading others; a 'military leader' individual oftentimes may end up promoted to Gamma, and be in charge of the Epsilons. Like other members of the council, they should be able to take care of the pack if something happens to the higher ranks.
Werewolves vary in style of relationships, just like humans do. It seems to be something that they are born with, like sexual preference. Some individuals seem to prefer serial monogamy, whereas others are of a more free nature.