Chimps Start Their Own Fashion Trend

A group of Zambian chimpanzees have been sticking a blade of grass in their ears. Is this the new stylish craze within the chimpanzee community? “This could be the equivalent of people wearing earrings or certain kinds of hats,” says researcher Edwin van Leeuwen.

Edwin van Leeuwen, a primate expert at the Max Planck Institute, in The Netherlands, first noticed the behavior in 2010. Julie, one of the chimps in Zambia’s Chimfunshi Wildlife Orphanage Trust sanctuary, repeatedly put a stiff, straw-like blade of grass in one or both of her ears for no apparent reason.

A chimpanzee donning the "grass in the ear" look in the
Zambia Chimfunshi Wildlife Orphanage.
 (Photo by Liz Simon/National Geographic) 

The Study:

Over the course of several visits, Leeuwen noticed that other chimps began to follow suit. Eight of the 12 chimpanzees in her group mimicked Julie’s behavior. “They spontaneously copied the arbitrary behavior from a group member. Chimpanzees have a tendency to learn from one another – clearly a case of “monkey see, monkey do” in fact,” van Leeuwen said.

Van Leeuwen’s team studied 700 hours of video footage to understand how the ‘grass-in-ear’ trend developed in four groups of chimps. The “grass-in-ear behavior,” as scientists have termed it serves no apparent purpose. The blades of grass appear to be ornamental like jewelry or fashion similar to a human fad.

A chimp puts a blade of grass in their ear.
(Photo by Liz Simon/National Geographic)

But Why?

Scientists concluded that there are no genetic or ecological factors that influenced this behavior. Instead culture seems to be the only thing to account for it. “The fact that these behaviors can be arbitrary and outlast the originator speaks to the cultural potential of chimpanzees,” van Leeuwen said.

The grass shows artistic conceptualization, pre-planning, and tool-use. It is as if the grass identifies chimps as members of a team or a social club. This behavior may prove that the primates are capable of creating their own culture. “The observations show that there’s nothing random about individual chimpanzees sticking grass into their ears,” van Leeuwen said.

Van Leeuwen suggests that those animals that find a specific behavior somehow rewarding will continue to do so on their own. When Julie, the chimp who originated the behavior, died, other chimps continued the custom. Which means this fad could be hot for a while.

Video: 

Two chimps put grass in each other's ears (Video courtesy of the London Times)