For young men from the Maasai tribe of Kenya, spearing an elephant is part of the transition to manhood. The farmers of the Kamba tribe pose no threat to elephants, however. New research shows that wary pachyderms in Kenya's Amboseli National Park have learned to distinguish between the two groups based on odors and colors. The findings demonstrate the animals' ability to accurately classify threats from indirect cues.
The Maasai are a cattle-herding Kenyan tribe who habitually wear red or other deep, rich colors. Although the practice is now illegal, young Maasai continue to spear elephants as a rite of passage. Other ethnic groups in the area do not harass elephants, and researchers working in the park noticed that the local herds reacted differently to Maasai than to these groups.
To determine how the elephants discern a Maasai from a Kamba, evolutionary psychologists Lucy Bates and Richard Byrne, both of the University of St. Andrews in Fife, U.K., and colleagues recruited male volunteers from both tribes and gave them red clothes to wear for 5 days. The team then placed the fragrant garments upwind and out of sight of 18 different elephant family groups. Both types of clothing elicited more of a response--tensing, sniffing the air, and moving away--than did unworn duds of the same color, but the reaction to Maasai smells was much stronger. In a paper published online 18 October in Current Biology, the team reports that the animals moved away 27% faster and 65% farther from the Maasai scents than from Kamba odors. "If they got a whiff of the Maasai, they would just be running away," says Byrne.
The team also tested the effect of color alone, draping unworn red and white clothes over bushes along elephant travel routes. Rather than running away from the clothes, the elephants behaved aggressively--particularly toward the red clothes. Byrne explains the contradictory response by noting that the relatively weak-eyed animals didn't see the clothes until they were within about 4.5 meters; their finely honed noses would have picked up the scent of a real Maasai long before they got this close. Without smell acting as a fear stimulus, says Byrne, the elephants react angrily toward a color they had learned not to like.
"It's really interesting to see how sophisticated and appropriate the elephants' responses were to the smells and garments associated with people who presented different levels of predator threat," says animal communication expert Karen McComb of the University of Sussex, U.K. According to McComb, anecdotal evidence has hinted that elephants are discerning about humans, but this study is the first to tackle the question in a controlled way.