A husband and wife who study brown bears from a tree stand in the Alaska wilderness believe the huge carnivores are among a small group of intelligent animals that are playful all their lives.

Brown bears, or grizzlies, play games with each other and appear captivated by tree limbs, stumps, stones and tall grass. Their hijinks don't stop as they grow from cubs into adults, says Bob Fagen, an animal behavior specialist and associate professor of biometry at the University of Alaska."It looks like the brown bears of Pack Creek may be one of the rare species that play the same amount through all of their lives," Fagen said.

That puts them in the company of chimpanzees, lions, wolves and several domestic animals, those Fagen calls "a small select group of intelligent, social, cultural species."

Mrs. Fagen has watched cubs playing chasing games, and she saw an older bear lie on its back and roll a huge, rotted stump atop its upended paws. The Fagens saw an adult male and female sliding down a patch of snow, apparently in fun, during the mating season.

Mrs. Fagen also suspects that bears indulge in pleasures humans might not recognize: rolling in dead fish, for instance.

The Fagens hope their study of play will add to broader research into how bear behavior is molded. "We want to look at the little ways and big ways that behavior is passed between generations, other than genetically," Fagen said.

The Fagens know that cubs tend to use their mothers' fishing territory even after they leave her side at 2 to 3 years of age. By tracking play and foraging patterns, they hope to find out if cubs also adopt their mother's fishing techniques and personality traits.