Wittemyer, whose team reports its findings today in the Proceedings of the Royal Society B, says the elephants may be willing to accept nonrelatives into their group to ensure they have the critical mass needed to gather food and protect themselves.
"The results indicate that the illegal killing of elephants can erode the genetic basis for their social structure but does not necessarily destabilize their social organization." Coauthor Iain Douglas-Hamilton, an Oxford University zoologist who also directs the Kenya-based Save the Elephants charity, says the research "helps us to understand the extent to which an elephant society is disrupted by ongoing mortality from poaching but can yet adapt and recover."
Still, wildlife biologist Kathleen Gobush, who studied elephant groups as part of the University of Washington's Center for Conservation Biology, says that mixing with nonrelatives can come with "real longterm costs." Gobush and colleagues found similar nonkinship elephant groups in a shorter-term study of elephants in Tanzania's Mikumi National Park, where poachers killed three-quarters of the elephants before the 1989 ban on the ivory trade.
In a separate study about to be published, Gobush also found evidence that such mixing causes "significant behavioral differences" between elephant groups of kin in contrast to groups of non-kin. For example, she says, mixed groups showed aggressive behavior at water holes more often than groups composed solely of kin.
Other elephant experts say they are intrigued by the findings but would like to see similar studies in other populations. Ecologist Caitlin O'Connell-Rodwell of Stanford University in Palo Alto, California, studies elephants in Namibia and says that "it would be great to get this kind of data from other disturbed populations to see if the pattern is consistent or just a local phenomenon that could have other explanations." Source:sciencenow.sciencemag.org