Green’s Dictionary of Slang

(US) a juvenile or prison gang.

1972		(con. 1950s) D. Goines Whoreson 178: The wild young boys on the ward gathered around me and we started a wolf pack. If one fought we all fought.
1978		R. Caron Go-Boy! 38: Suddenly I became aware that one of the wolf packs was stealthily circling me. [Ibid.] 283: Wolf packs were roaming everywhere, looking for food, sex, or just thirsting for blood.
2000		P. Beatty Tuff 34: Before the sex fiend noticed the red-eyed wolf pack surrounding him, they were on him.