Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-70.62.56.205-20130725042949

in the new episode visonary, peter explains that his sister (dereks mom) could turn into a full wolf which was very rare and she was consulted because of this status. So my question is, why wasnt peter the same way with his transformation?????? he became a large wolf like beast which was again rare for werewolves to do. 