18 October 2007
NewScientist.com news service
Elephants can sniff out human friends from foe, suggests a new study which shows the big mammals can recognise the smells and clothing of different ethnic groups.
African bush elephants (Loxodonta africana) in Kenya’s Amboseli National Park flee from the scents and colours of clothing worn by Masai warriors, but are not bothered nearly as much by the scent or sight of garments worn by local farmers.
The findings may be the best evidence yet that animals apart from humans can differentiate groups of individuals within other species.
"They are defining groups that pose different levels of risk within the human species," says Lucy Bates at the University of St Andrews, UK. "This is the most sophisticated level of group identification within species for any animal other than people."
Bates and colleagues placed three samples of red clothing near the elephants. One of the pieces of fabric was clean, the other two had been worn for five days, either by a Masai or Kamba man.
Traditionally, young Masai men spear the elephants to demonstrate their virility, and despite a longstanding ban on the practice, this occasionally still happens. The Kamba however, are an agrarian group that pose little threat to the animals.
Clothing worn by the Masai caused the elephants to run faster and further from the test site than either clean or Kamba-scented clothing. The elephants also reacted more aggressively towards clean red clothing, a colour typically worn by the Masai, than to clean white clothing often worn by the Kamba.
Learning by association
Bates says similar group detection has been observed in seals in western Canada that can recognise different pods of their whale predators by each group’s unique song. She feels the elephants’ ability is more advanced, however, as individual human smells are more nuanced than shared whale songs.
"The mechanism of learning by association is not that unusual," notes Marc Hauser, an animal behaviour specialist at Harvard University in Cambridge, Massachusetts.
He points out that previous research on vervet monkeys within the same national park shows that they flee at the sound of mooing cows – noise associated with the cattle-raising Masai – but not at wildebeest sounds – wild animals not associated with the Masai.
Journal reference: Current Biology (DOI: 10.1016/j.cub.2007.09.060)