Just spent glorious day fishing with my 12 year old nephew, James. This thought occured: two together is fine, but a gang is best. Particularly for teenage boys - whatever your mum and Ol Man Krupke tell you. "Join a gang, any gang" said the late Kurt Vonnegut.
While you and I might find a gang of adolescents disturbing or frightening (and they might enjoy engendering that response in us), the truth is that they are merely doing what all humans do: gather together for safety, reassurance and cooperation.
Hat tip to Charles for spotting Vonnegut's version of this idea in a late interview...