By that definition, the jungle is full of horseplay. Recreation is well documented in big-brained birds, such as crows and hawks, which chase each other and drop and catch objects seemingly for the hell of it. For other animals, the data is sketchier, often relying on just one case, but does suggest that play beyond birds and mammals is indeed possible. A Komodo dragon at the National Zoo in Washington, D.C., plays tug-of-war with its keepers, and soft-shelled turtles at other zoos push balls with their snouts and swim through hoops. Wild-reared octopi entertain themselves in the lab by towing toys or passing them between tentacles. Another study documents what seems to be wasps play-fighting.