Trainer Danielle Faucett rewards Brittany the elephant after making a painting at the Milwaukee County Zoo. The artwork gets professionally mounted and is sold at the zoo's gift shop.

Milwaukee ? Brittany wields her paintbrush with confidence, slapping it roughly against the canvas to produce streaks of green or smears of orange. With apparent pride, she steps back, inspects her work – and extends her trunk to receive a freshly loaded paintbrush.

Brittany, an African elephant, is doing her small part to pay her way at the Milwaukee County Zoo. Her artwork is sold at the zoo’s gift shop to raise funds.

This painting pachyderm is far from the only artistic animal in captivity. For years zoos and aquariums across the country have encouraged animals to paint as a way to keep the penned-up denizens mentally enriched. Typically, the paintings were discarded or set aside.

But officials have recently discovered that animal lovers are willing to pay hundreds – or even thousands – of dollars for the creatures’ creations, prompting zoos across the country to study whether their animal artists might be an untapped source of revenue.

The Milwaukee zoo’s gift shop sells about 36 of Brittany’s paintings each year for $30 each.

“She really seems to enjoy painting – she likes creating new things,” elephant trainer Danielle Faucett said. “But we only do it about once a month because we want to make sure the activity remains mentally stimulating.”

Brittany is an eager artist. Her ears flare out as she attacks the canvas, swiping at it almost like Zorro wielding a sword, and she finishes in a matter of minutes while Faucett coos words of encouragement.

The menagerie of animals that can brandish a brush is seemingly endless. At zoos nationwide, painters include chimpanzees, kangaroos, ocelots, red pandas and even a rhinoceros and Komodo dragon, said Jackie Marks, spokeswoman for the Association of Zoos & Aquariums in Silver Spring, Md.

One especially profitable painter is Towan, a 40-year-old orangutan at the Woodland Park Zoo in Seattle. For Valentine’s Day, the zoo auctioned a pair of his paintings on eBay for a total of more than $1,300.

As lucrative as Towan’s works have been, keepers can only get him to produce a limited number of paintings.

“If you try to get him to do it two days in a row, he won’t pick it up on the second day,” said zoo spokeswoman Gigi Allianic. “You can’t make it routine for the animal or they lose interest.”

That’s the challenge for most zookeepers, who say they won’t sacrifice an animal’s enrichment for the sake of making a quick buck. Also, some animal artists can be as temperamental as their human counterparts.

Sea lions ply the painting trade with their mouths – they hold a stick in their teeth from which a paintbrush juts out in a T shape. But when they don’t want to paint, no amount of cajoling can convince them otherwise, said Henry Kacprzyk, a curator with the Pittsburgh Zoo & PPG Aquarium.

“If they don’t want to participate, they’ll just ignore you, they’ll leave,” he said of his zoo’s three sea lions. “There’s not much you can do – they swim faster than we do.”

Artistic “talent” seems as diversely distributed among animals as among humans, zoo officials say. Just as some people are more artistically inclined than others, so, too, is the case for chimps, elephants and so on. Some animals are eager participants while others turn up their noses – or trunks – at the sight of a brush.

Of course, beauty – and artistic talent – are in the eyes of the beholder. People who buy animal paintings are rarely art aficionados. Instead, they’re typically animal lovers who know the money is going toward a good cause.

But some animal artwork can be surprisingly valuable, none more so than three paintings produced in the 1950s by a chimpanzee named Congo. The abstracts sold in 2005 for a total of $26,352 at a London auction where competing works by Renoir and Andy Warhol languished unsold.