They say elephants never forget, but their brainpower does not stop there. A new study suggests that pachyderms can distinguish threatening groups of people from those who mean them no harm.
Researchers working in Kenya presented the animals with identical red garments worn for five days either by Maasai tribesmen, who slay elephants to prove their strength and daring, or by farmers of the Kamba tribe, who leave the pachyderms in peace.
The beasts turned tail and ran after sniffing the clothing worn by the Maasai but had much less reaction to the odor of the Kamba, according to a report published in Current Biology. The same elephants responded aggressively toward unworn red robes—the traditional color of the Maasai—but not toward odorless white clothing.
"It tells us a bit about how elephants classify the world," says evolutionary psychologist Richard Byrne of the University of St. Andrews in Scotland. "Instead of treating humans as all one set, they're able to discriminate within one set."
Human minds effortlessly extract key characteristics common to groups of objects, he says, such as the redness of apples. But researchers are less sure whether animals can form similar categories.
Byrne says he, St. Andrews colleague Lucy Bates and the other team members began their experiment after talking to members of the Amboseli Elephant Research Project in Nairobi, Kenya, who told tales of odd elephant behavior.
"There were a number of reports of very inquisitive and sometimes aggressive reactions of elephants toward signs of Maasai, but not towards people brandishing spears," he says.
Researchers have found that individual elephants can identify one another as strangers or old friends. Byrne says the fact that elephants seem to pick out particular cues from their environment that mark Maasai warriors suggests that the animals can actually classify whole subsets of a species based on the threat they pose.
The elephants' different reactions to smell and color make sense, he adds, because the odor of a Maasai hunter implies that he is nearby, triggering fear that sends the pachyderm packing.
"It's an innovative way of getting at the problem" of what animals know about their environments, says Karen McComb, an expert in mammal communication and cognition at the University of Sussex in Brighton, England. "The response is very appropriate to knowing what the threat was. It's suggesting they have some sort of reasonably advanced understanding of the sorts of cues that are going to be dangers."
As for what goes on in their heads and whether it resembles human consciousness, she adds, "we can only guess."