Elephants Use Smell of Fear to Sort Friend from Foe
Scientific American, October 18, 2007
http://www.sciam.com/print_version.cfm?articleID=B4F19421-0EA5-62AE-89758AC94F723D17
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 robesthe traditional color of the
Maasaibut 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."
