The star trotted toward a small pad in the middle of the 80-foot stage and stopped on his mark.

"Look at the camera!" veteran animal trainer Steve Martin commanded.

Like a true pro, Shadow, a gray wolf who has made appearances on HBO's "True Blood" series, turned his head and fixed his piercing yellow eyes at the camera operator.

"Good boy," another trainer said, tossing him a morsel of meat.

The shot was among several animal scenes filmed on the giant green-screen stage at Hollywood Center Studios last week, where a leopard, a lion, a monkey, an elephant and even two grizzly bears performed simple tasks on the empty stage as a film crew captured their movements, snarls, roars and grunts.

The entire GreenScreen Animals production cost nearly $100,000. The Santa Monica company specializes in selling hard-to-get stock footage of animals against the backdrop of green screens that can represent any background desired - a forest, a mountain, a parking lot or a school crosswalk.

"The vampire genre is huge right now, so that's why we're shooting wolves," Mark Shockley, co-owner of GreenScreen Animals, said in a break between filming last week.

His company has created a library of some 3,000 animal clips for television shows, commercials, movie trailers, talk shows and video games. GreenScreen Animals retains the rights to the clips, which it sells for between $500 and $4,000 each, depending on the type of production.

Although the growing use of digital effects has reduced demand for animals on sets, many producers around the world who can't afford to film animal scenes or hire a visual effects firm to create one on a computer use GreenScreen Animals' stock footage to digitally insert an animal into a commercial, a sitcom or a movie trailer.

The privately owned company does not disclose its financials but said sales have jumped nearly 300 percent over the last five years.

"Animals never go out of fashion," Shockley says. "Our footage is only going to grow in value."

Green Screen Animals' diverse clients have included "The Tonight Show" with Jay Leno, an A&E nature documentary, the Disney Channel shows "Austin & Ally" and "Good Luck Charlie," the interactive book series JibJab.com, and various movie trailers, including one for 20th Century Fox's "We Bought a Zoo."

Commercials also are a big source of business for GreenScreen. Last year the business filmed a commercial for Sprint that featured a cat driving a car. The cat was actually filmed while perched on an apple cart and pawing a steering wheel prop. Another spot for Free Credit Report.com showed a monkey popping out of a shopping bag.

Half of the company's business comes from customers in Britain, Australia, Japan and Eastern Europe. Foreign producers and advertising agencies have an especially strong appetite for images of large North American animals, particularly grizzly bears.

Shockley, who has a background in commercial production and movie marketing, hatched the idea for his business while helping his wife, Laura, an animal trainer, care for animals.

"I love animals and I love production," he said. "I thought, how can I combine these two passions? I researched it and realized nobody was doing this."

He launched the company in 2007 with Westley Koenen, a senior vice president at MasterCard Worldwide. The partners lined up financial backing from three primary investors: Southern California entrepreneur Rob Goldberg, founder of GMG Entertainment and a former executive at Launch Media, later sold to Yahoo; Laura Conrad, former chief financial officer at Experian; and Kip Knight, president international of H&R Block.

The use of animals in film and television productions has become increasingly controversial. HBO shut down its drama "Luck" last year after three horses died during production.

But Shockley works closely with a group of veteran trainers to ensure that animals are not harmed during shoots, which are monitored by the American Humane Assn., the group charged with overseeing the welfare of animals on film and TV sets.

"So often, even stock footage cannot guarantee that the original animals used were treated humanely," said Karen Rosa, senior advisor to the AHA's film and television unit.

"GreenScreen Animals has always been collaborative and has wanted us there to ensure the animal's safety and award our certification, 'No Animals Were Harmed.'"

Shockley added: "If an animal doesn't want to do a scene, it's OK. I haven't got the pressure of a $30-million movie where if I don't get the shot, I'm done."