Dark energy is thought to comprise 72 percent of the universe
Dark matter makes up another 24 percent
Which means that the matter making up you and me accounts for only 4 % of the universe.
Yawning is a social behavior and could be contagious in human. Certain fishes, animals do yawn to scare their enemies.
When a lioness in a group yawns, it might be signaling to move on to the other lioness in the group.