Are animals happy in zoos?

That's a question more and more zoo visitors are asking, says Jeanette Beranger, a lead keeper at Roger Williams Park and Zoo in Providence, R.I. -and one that zookeepers make it their business to answer in the affirmative.

When animals develop negative behaviors, it can be a clue they are bored, unhappy, or unhealthy, says Joel Hamilton, one of two animal curators at the zoo.

Recently, he says, one of their kookaburras lost a mate. For five days he stopped eating and making the distinctive call those birds are known for. Keepers attributed his behavioral changes to his loss.

"The degree of change is what's at question," Mr. Hamilton says. "A lot of people associate human emotional attributes to whatever animal they are looking at. That animal may or may not have those attributes."

For instance, the world through the eyes of a lion is black-and-white, so to speak. "It's 'food or not?' or 'breeding or not?' " Hamilton says. "They don't sit there and think, 'The sky's kind of blue today. Isn't that nice?' "

Most animals spend their days foraging for food and evading predators.

"Those pressures are removed when they are in captivity. Hence, we have to deal with things like obesity. They don't have the impetus to move around like they would in the wild," Hamilton says.

The whole field of "environmental enrichment" is designed to make sure animals get the mental and physical stimulation they need every day.

Take birds, for instance. Instead of giving them rigid sticks for perches, zoo keepers devise flexible perches attached to bungy cords. That forces the birds to get their balance, use their leg muscles, and exercise.

Both Hamilton and Beranger say many zoo staff members would rather see those animals in the wild and not in zoos - but human destruction of natural habitat makes that very difficult.

"The world is a shrinking place. There are plenty of animals that wouldn't exist if it weren't for zoos," Hamilton says. "It would be wonderful if we could say we don't have to worry about elephants again, but that isn't reality."

(c) Copyright 1999. The Christian Science Publishing Society