The “wolf-pack” model originated in mid-20th-century wolf research on captive animals. Rudolf Schenkel’s 1947 study of zoo wolves described rigid dominance ranks (with “alpha” males/females) .  L. David Mech later popularized these ideas in his 1970 book The Wolf, spreading the notion that a pack was led by an aggressive “alpha” .  Popular dog-trainers adopted this model (e.g. the “alpha dog” concept in media).  However, these early studies were on unrelated wolves forced to