This Is Why We Yawn [VIDEO]

Did you just yawn by reading the title? Almost all animals with a spine yawn. Some species yawn as a social ritual, others to realign their jaw. But why do humans yawn? Check out this cool video on why we yawn.
Did you just yawn by reading the title? Almost all animals with a spine yawn. Some species yawn as a social ritual, others to realign their jaw. But why do humans yawn? Check out this cool video on why we yawn.