If someone around you yawns, the chances are that you too will soon yawn. In orangutans it has now been found that scratching is very contagious. This is what cognitive psychologists from Leiden discovered at Apenheul Primate Park. Publication in American Journal of Primatology.
Click here for original story, Scratching is contagious when solitary orangutans are in groups
Source: Phys.org