Chimpanzees form new traditions by copying each other; researchers found a new trend in the chimpanzee community is a piece of grass hanging out of the ear.
Researchers watched 700 hours of video to see how it came about; they noticed one chimp stuck a piece of grass in her ear and the others followed suit, a Springer news release reported.
The study was published in Springer's journal Animal Cognition.
In 2010 researcher Edwin van Leeuwen of the Max Planck Institute for Psycholinguistics in The Netherlands noticed a female chimp named Julie repeatedly put a stiff straw like blade of grass in one or both of her ears and left it there.
The researchers collected 740 hours of footage and monitored 94 chimpanzees to see if the trend caught on. The chimps lived in four different social groups, only two of which could see each other.
The researchers found only one of these four groups regularly performed the "grass-in-the-ear" behavior; one chimp in a different group performed the action once. Eight of the 12 chimpanzees in Julie's group repeatedly placed grass in their ears. The first one to copy her was her own son, Jack, followed by other individuals she regularly interacted with. Generally at least two of the chimps performed the action.
The observations show the grass-i-ear action is not random but rather comes from a tendency to elarn from one another. The study gives a literal demonstration of "monkey see, monkey do." And the researchers suggests chimps find this type of behavior rewarding.
"This reflects chimpanzees' proclivity to actively investigate and learn from group members' behaviors in order to obtain biologically relevant information," van Leeuwen said. "The fact that these behaviors can be arbitrary and outlast the originator speaks to the cultural potential of chimpanzees."
