A team of researchers spent weeks playing human-vs-rodent hide-and-seek, which was so much fun that the rats giggled and jumped for joy. The researchers filled a room with hiding places made from different boxes, and the rats learned that if they began the game inside a closed box, they were the seeker, while being in an open box meant they needed to hide. Over time, the rats became stealthier, working out that opaque boxes make the best hiding places, and learning to check spots where their two-legged rival had hidden before when seeking. While learning to play the game, the rats were rewarded for success through tickles, strokes, and a bit of rough-and-tumble play. The rats would often leap away to hide in a new location once they'd been rumbled. Like excitable children, they wanted to keep playing again and again. While research like this can tell us more about learning in the mammalian brain, it can also help us better understand the importance of play.
But the tooth fairy does exist, right?
Historically hardcore
1. The story of Khutulun, who was Genghis Khan's great-great-granddaughter. She said she would marry whomever could beat her in a wrestling contest. If she won though, they had to give her 100 horses. She died unmarried, with 10,000 horses.
