Humans aren't alone when it comes to yawning — all vertebrates do it too, including fish, amphibians, reptiles, birds and mammals. But why? The "evolutionarily ancient" act of yawning likely serves a ...

Researchers believe the yawning robot may have triggered some biological mechanism in the chimps that they associated with sleep. Image: Popular Science composite, Getty Images/ RMJM, Aline ...

Why do we yawn? Yawning is a universal gesture. Everyone yawns, from babies still in their mother's womb to the elderly. However, the exact reasons for this reflex are not well understood. Is it just ...

Yawning isn’t the only bodily function that’s contagious. Japanese scientists have discovered that chimpanzees are more likely to urinate when they see other primates going No. 1 as well, as detailed ...

Is it true that we yawn when our brains are deprived of oxygen? Most of us can feel a yawn coming on. The muscles in our jaw ...