Chimpanzees in Zambia insert sticks into their ears and anuses, mimicking human caretakers, researchers find.

Chimpanzees at a wildlife orphanage in Zambia have been observed inserting grass and sticks into their ears and anuses, a behavior that started 15 years ago and has resurfaced. Researchers suggest chimps may have learned this from caretakers cleaning their ears. This trend, published in the journal Behaviour, shows how social-cultural practices spread among primates, similar to human fashion trends like earrings.