According to the author, bestiality has received scant and unsatisfactory attention in the literature. He reports four cases and concludes that bestiality should be viewed not as a substitutive phenomenon but as a perversion, similar to other perversions. In castration anxiety, there is regression to the anal-sadistic phases with bestiality accompanied by sadistic fantasies or sadism which, in turn, operate defensively by disrupting relations with others. In these patients feelings cannot be properly expressed toward people; they relate only to animals which act as surrogates, usually for parents.