Kids' Game or Animal Instinct?

For Humans, Birds, Even Tai Shan, Frolicking Is a Tool for Survival

Five million years of human evolution and it has come to this: Alyssa Christian climbing on a rock. After a cranky, cross-country flight from Los Angeles to see the rare baby panda at the National Zoo, the 5-year-old is not even looking at the intolerably cute little creature sitting in a tree busily tugging on the branches until they wave.

"We come to see one of the most unusual things in the world . . ." her exasperated father starts.

I'm being a panda, Alyssa explains, giggling. A mama panda.

Child's play, right? Silly. Pointless. A bit aggravating at times for adults, but harmless. Tai Shan does it, too, aimlessly scampering up a tree while his real mother snoozes below in her cave.

It's summer in Washington, and a playful spirit is in the air. School's out, Congress will soon go on recess, and worker bees who may feel like slacking off are transforming large swaths of Washington into a summer playground. At the National Zoo, if you are there at the right time -- morning and dusk are best -- all sorts of creatures are cavorting, including young Homo sapiens . The zoo gets 3 million visitors a year, about half of them from the greater Washington area. And most come now, during the warmer months.

But all humans, most other mammals and even ants play -- even politicians and K Street lawyers play -- and for important reasons. Play is so important, in fact, that there are scientists who dedicate their lives to studying it. They say two things: Play has a purpose -- although they're not entirely sure what it is -- and play is inextricably linked to why humans and some animals have large brains, extended childhoods and relatively long lives.

In other words, a number of species can't live without play.

At the National Zoo on a recent hot summer day, the western lowland gorillas swung laconically from branch to branch in their glassed-in habitat. In a pool down the way, the year-old sea lions, Summer and Calli, blew bubbles at each other. And three enormous pelicans flapped their enormous wings and chased one another. Some days they lunge at butterflies with no intention of catching them, seemingly for the heck of it.

Scientists have found that cats, dogs, otters, dolphins and wolves play. Ravens throw sticks. Rats like to wrestle. Penguins play king of the hill. And there's evidence that ants chase one another for fun. Parrots and badgers are among animals known to turn somersaults.

A few years ago at the zoo, a soft-shelled African turtle named Pigface was mauling himself. So zookeepers gave him balls, sticks and hoses to distract him. He started to play.

Then there was Kraken, the zoo's Komodo dragon, who often shook shoes around, just like puppies do.

And on this day at the zoo, there was, as well, the shrieking, swirling free-for-all at the Pizza Garden, a giant plastic playground, the perfect habitat for juvenile human play.