'Monkey See, Monkey Do?': Chimps Keep Up with Social Trends

Just like humans, chimpanzees, too, like to spruce up their style. A recent study published in the journal Animal Cognition found that chimpanzees also like to keep up with the latest fashion trends going around. 

After many fellow chimps saw female Julie place a piece of grass in her hair--for no apparent reason--many of the animals jumped in on the fashion trend.

"This reflects chimpanzees' proclivity to actively investigate and learn from group members' behaviors in order to obtain biologically relevant information," said lead study author Edwin van Leeuwen, of the Max Planck Institute for Psycholinguistics in The Netherlands, in a news release.

Over 700 hours of video footage documented the trend. Prior to that, van Leeuwen had first noticed that Julie would repeatedly put a stiff, straw-like blade of grass in one or both of her ears back in 2010. Even while grooming, Julie left the objects in place. Over time, other chimps starting mimicking a similar look to Julies'. 

In order to find out why this was happening, van Leeuwen conducted a year-long study that examined 94 chimpanzees living in four different social groups in a sanctuary. The findings revealed that one of the four groups regularly performed Julie's grass trick, which convinced eight of the 12 chimps in the group to also go for the same look. Even after Julie died, the trend is still going strong, according to researchers.

"The fact that these behaviors can be arbitrary and outlast the originator speaks to the cultural potential of chimpanzees," van Leeuwen concluded.

"Monkey see, monkey do?"