At the sight of human visitors, the adult lion rises from his slumber and prowls to the front of a wooded enclosure on the grounds of the fifty-acre International Exotic Animal Sanctuary, about forty minutes north of Fort Worth. He makes a chuffing noise, poised somewhere between a growl and an exhalation. He bares just a hint of teeth.

This is the moment when most visitors, even if separated from the lion by a fence, take a big step back.

Yet Louis Dorfman, the self-trained animal behaviorist who is the chairman of this nonprofit organization, opens the enclosure’s entry gate and steps inside. The lion calmly sidles up next to him.

“That sound he’s making is just him saying: ‘It’s okay. I recognize you. I respect you. I’m glad to see you,” he said.

Dorfman, 75, took a leadership role at the International Exotic Animal Sanctuary seventeen years ago, after a previous owner operated the facility inappropriately. Although he  has a law degree and currently serves as the chairman of the Dallas-based Dorfman Production Company, he has managed to devote countless hours to promulgating a personal philosophy of animal care that he calls “emotional enrichment.”

The idea is for keepers to develop a mutually respectful relationship with the animals and provide companionship that the animals might otherwise miss in a captive setting. Dorfman personally interacts with many of the 78 animals at the sanctuary, touching noses with the bears and sometimes taking naps with the big cats. He also encourages staff members to pay careful attention to the moods and individual personalities of the animals.

“I don’t try to discipline them. I don’t give them treats. I don’t give them any incentive other than an emotional relationship,” Dorfman said. “The animals choose to modify their behavior because they want me with them.”

Dorfman’s efforts to promote his ideas and to see them become commonplace practice seem to be gaining traction. Last month, the sanctuary enjoyed a considerable publicity boost when it welcomed eleven bears that had been grossly mistreated at the Chief Saunooke Bear Park in North Carolina.

Meanwhile the Association of Zoos and Aquariums is overseeing a series of experimental studies on emotional enrichment, partly financed by Dorfman. Some of the studies explore the neuroscience of calmative behavior.

Many zookeepers around the country already employ their own variations on these techniques. But emotional enrichment is not yet being practiced or taught on an institutional level at zoos or in animal sciences university programs—something that Dorfman would like to see change. The first round of studies is expected to be completed next year.

“People in the zoological community began to think about animal enrichment twenty years ago,” said Paul Boyle of the Association of Zoos & Aquariums, citing practices, now widespread, like offering zoo animals toys to play with or hiding their food to replicate the experience of foraging in the wild.

According to Boyle, the association’s senior vice president for conservation and education, Dorfman’s theories represent “a natural evolution, and many institutions are thinking about this.”

Nonetheless, the sight of Dorfman crouching beside a brown bear and patting its head as it eats a lunch of raw meat, melon, and avocado can be jarring.

Indeed, there are countless stories of human-animal relationships gone bad. They include the death of the naturalist Timothy Treadwell, who spent thirteen summers in Alaska living with grizzly bears before they killed him,and mauling by the Las Vegas illusionist Roy Horn in 2006 by one of the white Bengal tigers that performed in the Siegfried and Roy stage show.

Dorfman argues that tragedies like those occur when humans stop paying heed to the signals animals are sending or when they romanticize their relationships with the creatures. Not all animal professionals have the temperament required to get as close to the animals as he does, Dorfman acknowledged, but he believes that emotional enrichment can be practiced without direct contact.

“I wouldn’t say there’s resistance to what we’re doing, but I would say there is some people not understanding,” said Richard Gilbreth, the sanctuary’s executive director. “The problem is that when someone is afraid of something, they usually just don’t understand it.”

On a recent morning, the animals seemed to be responding favorably to Dorfman’s methods. After just a month in their new home, Dorfman said, the North Carolina bears were more social and relaxed.

As for the big cats, Dorfman escorted a visitor—along with Gilbreth and the sanctuary’s lead keeper, Nissa Marione—to a large enclosure and instructed the group to wait outside the fence. A few minutes later, he emerged in the distance, walking alongside a 500-pound white Bengal tiger. Species differences notwithstanding, they looked like two longtime acquaintances taking a leisurely afternoon stroll through the park.

“I know when the big cats are feeling irritated. I know when they are feeling perfectly content and want to say hi,” Marione said as she stood behind a fence and watched Dorfman. “But in terms of being able to do what he’s doing right now, I don’t ever foresee myself being able to do that.”