Slotow et al, “Killing of Black and White Rhinoceroses by African Elephants in Hluhluwe-Umfolozi Park, South Africa” — we learn that between 1991 and 2001 the park’s elephants dispatched 63 rhinos, mainly by goring. The authors suggest that the animals responsible were young males who had grown up in social groups from which older males had been “culled” (read: slaughtered by government-commissioned hunters as a population-control measure) and as a result entered a state of heightened, testosterone-fueled aggression called musth much earlier in life than they ordinarily would have. Since similar incidents at Pilanesberg stopped after large adult males were reintroduced into the population, thus reestablishing the natural male hierarchy, the authors advocate trying the same thing at Hluhluwe-Umfolozi.

via http://atlanta.creativeloafing.com/gyrobase/the_straight_dope/Content?oid=523975