Yawning isn’t the only bodily function that ... periods and certain “nonhuman animals” have long been believed to ape each other’s peeing times, the theory had not yet been battle ...

You know the feeling. It’s getting close to bedtime, you get sleepy, and you start yawning automatically. You may even find yourself yawning in the middle of the day in a mid-day lull.

However, unlike yawning, social proximity was not the determining ... including studying other ape species such as bonobos. Matthew Campbell, a psychologist at California State University Channel ...