Male elephants raised without male adult role models in the Pilaneserg reserve in South Africa began exhibiting tragically aggressive tendencies. In 1993 one young elephant killed both a tourist and professional hunter; a year later, young male elephants began killing rhinos. 20 white rhinos were found dead, most killed in a two month period. Two years later, another 20 were killed, and in 1997 a young male was caught killing a white rhino.
These elephants were raised without adult role models, male or female. 18 orphaned elephants were released in the reserve in 1980. Two years later, they had already begun to behave aggressively. Adult females were released into the park, but the aggressive tendancies continued to worsen.
Elphant behaviourists decided to introduce male bull elephants into the reserve. Six mature males were released into the reserve. Once each of the six bulls had encountered every elephant in the park, the rhino killings stopped, with “no negative results.”
“There has been a total turnaround,” said Gus van Dyk, field ecologist at Pilanesberg. “A possible scenario,” says elephant behaviourist Robert Slotow, “is that it’s the older males disciplining the younger ones.”
Woops: That link no worky. This link to a more technical article does.