During a visit to the National Zoo in Washington, DC, biopsychologist Gordon Burghardt decided to peek in on a Nile soft-shelled turtle its keepers affectionately called “Pigface.” Pigface had been a zoo resident for more than 50 years, and Burghardt had seen him before, but this time, he noticed something a bit curious—Pigface was playing basketball.
“It was by itself,” recalls Burghardt, currently at the University of Tennessee in Knoxville, and “it had started to knock around” a basketball provided by its keepers. The year was 1994, and play had only rarely and anecdotally been reported in animals other than mammals, but he thought that might be what Pigface was doing. The 1-meter-long turtle exuberantly pushed the ball around its aquatic enclosure, swimming through the water with ease as it batted the ball in front of it with its nose. “If you saw a dog or an otter going around ...