Maltreated nestlings exhibit correlated maltreatment as adults: Evidence of a “cycle of violence” in Nazca Boobies (Sula granti)

. The “cycle of violence” hypothesis implicates child abuse as a cause of later violent behavior via social transmission between generations. It has received mixed support from human research and has prompted the study of nonhuman models with comparable abuse behaviors. The underlying biology of child abuse remains a controversial subject, perhaps partly because in nonhuman animals similar behavior occurs relatively rarely in wild populations. The Nazca Booby (Sula granti), a colonial seabird, provides a nonhuman model in which maltreatment of nonfamilial young is widespread under normal living conditions. Essentially all adults show social attraction at some point in their lives to the offspring of other parents, often with a sexual and/or aggressive motivation. Here, we show a correlation between the degree to which a young bird is targeted by such adults and its own infliction of maltreatment later in life. The results provide the first evidence from a nonhuman of socially transmitted maltreatment directed toward unrelated young in the wild.