In chimpanzee Val’s facial expression you can almost see a satisfied smile. What could be the reason for this? Perhaps the monkey is happy because it is just rocking the latest “fashion trend” of the chimpanzee world. Because the dry stalks, which protrudes from his left ear, is not an oversight, but an intentionally placed accessory, as biologists around Edwin van Leeuwen from the University of Utrecht found out. In a group of chimpanzees in the Chimfunshi Wildlife Orphanage in Sambia, they have observed several animals as to put them in their ears and their back.
A chimpanzee named Julie set the trend. In 2010 she started out of nowhere and apparently for no apparent reason to wear blades of grass in her ear. Shortly afterwards, seven fellow species from the sanctuary grazed this fashionable behavior and after July’s death, some of their group members continued the “tradition”. Regardless of this, another chimpanzee group in the Chimfunshi Wildlife Orphanage has started with body jewelry. Trendsetter this time: chimpanzees Juma. In August 2023 he was the first to put blades of grass in his ear. Within a week, four of his peers showed the same behavior. Eleven days after Juma had worn a blade of grass for the first time, he also started wearing the stalks in his butt. In the end, Van Leeuwen and his colleagues observed a total of eight out of eleven monkeys in his group as to how they wore grass on at least one or both parts of the body.
A statistical analysis by the research team shows that the chimpanzees have looked at the behavior from their conspecifics and not all came into the same idea independently. But how had Juma got on it in the second group? After all, he never got in touch with July’s group, who adorned himself with grass talle 13 years earlier than Juma. Their common example was apparently people: “Both groups in which the chimpanzees were in their ears had the same nurses. These nurses reported that they sometimes put a grass or match in their own ears to clean them,” explains Van Leeuwen. “The chimpanzees of one group then found that they could also put the grass in another place.”
Even if the apes are a kind of fashion trend without any purpose, the behavior of culturally is not pointless: “By copying the behavior of another person, you show that you perceive this person and may even like it,” explains van Leeuwen. “So it could help strengthen social bonds and create a feeling of belonging within the group, as is the case with humans.” Who knows, maybe even more chimpanzees will wear this natural fashion jewelry or even develop new trends.
