The naturally inquisitive elephants approached and examined the items, smelling and touching them with their trunks and turning and manipulating them with their trunks and feet.
In the experiment, the pachyderms paid little attention to the wood. Instead, they preferred to investigate the elephant remains, especially the ivory. On average each elephant spent six times as much time examining tusks as wood.
Researchers also found that the wild elephants spent twice as much time examining the elephant skull than the buffalo and rhino skulls.
However, few animals showed a strong preference for any particular elephant skull over another. This suggests that they were unable to discern the bones of their own relatives.
McComb argues that the elephants' keen interest in ivory may derive from their experience with living elephants, which use their tusks to forage and fight.
McComb is unable to explain how elephants are able to recognize the skulls of their own species with the tusks removed.
"It's possible that they learn these skulls belong to elephants from encountering them in the context of a decaying carcass," McComb said. "But we just don't know."
Bekoff, the University of Colorado behavioral ecologist, said, "We knew that elephants paid a lot of attention to carcasses. But we didn't know they were able to discriminate between the bones of different species. "
"Elephants are very social animals, which form extremely close bonds with group members. And it's not surprising that they would show keen interests in all elephant remains, not only kin," he added.
McComb, of the University of Sussex, argues that her study is consistent with many others that have hinted at altruism and empathy in elephantsfor example, documented cases of the animals assisting other injured elephants.
She says that elephants might show strong interest in the bones of their dead, because they are most likely to chance upon and investigate the remains of relatives who have died within a group's home range.
As for the erroneous suggestion that elephants congregate to die in so-called "elephants graveyards," McComb said, "collections of bones can easily be explained away by mass die-offs, due to drought or hunting."
Elephants' interest in their dead may be related to their strong social bonds. McCombs says the only other nonhuman animal known to show keen interest in their dead are chimpanzees. Both chimps and elephants are long-lived, social animals with big brains, she notes.
"Animals that are intensely social in life may be most likely to display an interest in their dead," she said. "But what goes on in their minds while they are doing this is a total mystery."
Earlier this month, the Kenyan government announced plans to delist Amboseli National Park, raising questions about the future of the elephants in the study and other wildlife protected in the 151-square-mile (392-square-kilometer) park.
Under the controversial plan, the park will be decommissioned to a game reserve run by the Maasai local authority, rather than the federal Kenya Wildlife Service.
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