Turns out that humans aren’t the only animals that contagiously yawn, reports NPR.
There’s still no consensus on the purpose of a yawn, says Robert Provine, professor of psychology and neuroscience at the University of Maryland, Baltimore County. Provine has studied what he calls “yawn science” since the early 1980s, and he’s published dozens of research articles on it. He says the simple yawn is not so simple.
“Yawning may have the dubious distinction of being the least understood common human behavior,” Provine says.