Monday, July 10, 2006; A16
Animal play is certainly adaptive ["Kids' Game or Animal Instinct? For Humans, Birds, Even Tai Shan, Frolicking Is a Tool for Survival," Metro, July 2]. But animals don't study evolution; they play for fun. As with food, sex or comfort, the anticipation of good feelings is a key motivator for play.
Besides mammals and birds, there is also evidence for play in reptiles, fish and even invertebrates. Captive octopuses given a Lego block were more likely to play with it -- pulling, pushing or towing it and passing it from one arm to another -- if they were recently fed, suggesting that it was recreational.
Animals' capacity for pleasure should inform our treatment of them. When we crowd pigs and chickens on factory farms or keep rats and mice in barren laboratory cages, we deprive them of opportunities to enjoy life.
for Responsible Medicine