The Tweet: “Chimpanzees can develop their own fashion trends.”

It seems our closest relatives in the animal kingdom share even more with us than we might believe. We don’t just have complex emotional behaviours and tools in common, now chimpanzees have been observed to use grass as a body decoration.

According to research published in Animal Cognition by Edwin van Leeuwen, a primate expert, the chimpanzees engaged in an ‘arbitrary tradition’ with no observable purpose. The chimps were observed to stick long blades of grass in their ear, copying one another: “Our observation is quite unique in the sense that nothing seems to be communicated by it,” says author van Leeuwen.

Four groups of chimpanzees were studied for a year by van Leeuwen and his colleagues to see if the behaviour was more than just random chance. Of the four groups, all living in identical conditions, only one group performed the tradition, and the researchers concluded it had no genetic or ecological benefit, so must have some form of cultural origin.

“The chimps would pick a piece of grass, sometimes fiddle around with it as to make the piece more to their liking, and not until then try and stick it in their ear with one hand,” van Leeuwen says. “Most of the time, the chimps left the grass hanging out of their ear during subsequent behaviour like grooming and playing, sometimes for quite prolonged times. As you can imagine, this looks pretty funny.”

The researchers believe that this behaviour could have started like any other tradition or cult in human society – for no purpose other than to fit in or communicate that you are part of the group: “Any kind of subculture fad in human culture, I’d say, could be the parallel to this grass-in-ear behaviour,” van Leeuwen says. “Perhaps wearing earrings or certain kinds of hats… everybody can wear rings in their ears, but you just have to come to the idea to do it.”

Image: Benjamin Jakabek/ Flickr

This post was first published on The Untweetable Truth (04/03/2014)