Jef Akst | Oct 1, 2010 | 10+ min read
By Jef Akst Recess Fish, reptiles, and even some invertebrates appear to play. But when is it play, and not something else? And why do animals do it? Illustrations by Kaitlin Beckett 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