When we started the 2 o'clock tour at the Colorado Wolf & Wildlife Center in the mountains above Colorado Springs, the wolves were napping, just as wild wolves do in the middle of the day. A woman in jeans and cowboy boots served as guide for our group — eight random travelers, most of whom simply had seen the road sign, pulled in and paid the $10 fee. She led us from one enclosure to the next to see animals with names like Princess and Wakanda — tossing them treats from a Ziploc bag, so we could hear their jaws snap shut. Then she led us in a group howl, hoping that some of the wolves would join in. "Ready?" she said. "One, two, three. ..."

Our first collective howl sounded more like the bawl of a dying cow, and a couple of the wolves flicked their ears as if irritated. "You guys are pathetic," the guide said. "Let's try it again." Finally a wolf stood up, shook the dust from his coat and gave a half-hearted howl. As the guide directed us toward the gift shop, where a bottle of wolf fur cost four bucks, she tossed a biscuit over the fence. The next tour would be in an hour. The Wolf & Wildlife Center hosts thousands of visitors each year in its mission to "educate the public ... about the importance of wolves, coyote and (foxes) to our ecosystem." It even takes wolves as "ambassadors" into classrooms and other public settings ranging from Colorado's ski towns to inner-city Denver.

Each captive wolf has its own story, as does every captive-wolf operation. It was almost feeding time when I arrived at Mission: Wolf, a remote 200-acre sanctuary nestled at the southern end of Colorado's San Isabel National Forest. Wearing blue rubber gloves, two knife-wielding volunteers sawed through frozen meat. They'd cook the meat, which had been donated, in a giant pot mixed with vitamins and kibble, and then serve it to the 29 resident wolves, using white five-gallon buckets with each animal's name printed on the side: Nyati, Ned, Merlin, Orion, Lily ... and Soleil, a female rescued from an owner who wanted a fighting wolf and kept her chained to a tree for five months.

"Get Face to Face with Wolves" is the catchy slogan of the Wolf Education and Research Center (WERC) in northern Idaho, which keeps about seven wolves on 300 acres. During my visit, I heard the epic story of a female wolf named Chemukh (the Nez Perce word for "black"). She'd been attacked and wounded several times by other wolves in her 20-acre pen and was desperate to escape. Most of the enclosure was double-fenced, but there was one single-fenced section, 13 feet tall, where staff entered during feeding times. As a safeguard, that section was electrified; it was also reinforced at the top with a lean-in of taut wires no more than three inches apart. Somehow, during October 2000, Chemukh clambered up that fence, even though it pulsed with 5,000 volts, resisting a caretaker's efforts to pull her off. She made it to the top, squeezed between the taut wires and leaped to freedom. WERC's resident biologist, Jeremy Heft, described Chemukh's escape: "It was sheer will." But Heft also said that, because Chemukh was a captive-bred, human-socialized wolf, she was doomed in the wild. She didn't know how to hunt large game, and even if she didn't starve to death, she would probably be killed by wild wolves or by people.

Heft came from Pennsylvania to be an intern at the center 14 years ago and fell in love with its wolves — "my new brothers and sisters," as he calls them on WERC's website. "The brutal extermination of wolves for unjustified reasons was a major rebellion platform for me and therefore I directed all my energy to fight for species that cannot defend themselves. ... My job remains far from ideal — strenuous labor ... on-call for problems all day, every day of the year; very few breaks away from camp; very little, if any, pay; no human social interaction outside of interns; no electricity or running water; living alone in a deep forest ... and the most difficult aspect: deciding when a brother must be euthanized and following through with the action. I have many scars (physical and emotional) ... Still, through it all I remain proud that I have provided the best life possible for the Sawtooth Pack," a group of wolves inside the WERC fences.

In five years of exploring the obscure world of captive wolves, I visited more than two dozen operations, driving on dusty back roads and interviewing biologists, geneticists and other experts. My quest was inspired by my own sad experience as the owner of a wolf-dog hybrid, because I realized that many of the issues with hybrids extend to captive wolves as well. Captive wolves don't get a lot of attention, as the public tends to focus on the more than 60,000 wild wolves in North America. But the number of wolves and wolf-dog hybrids in captivity is much greater: about 1,500 pure wolves whose captivity is federally regulated, plus untold wolves kept by unlicensed individuals, and an estimated 300,000 wolf-dog hybrids.

People who keep or work with captive wolves are often earnestly trying to help the species. Motivated by a desire to ensure the long-term survival of wolves, they use science to educate the public about this elusive and intelligent creature — an icon of the wilderness, especially in the West. Many make enormous personal sacrifices, running their facilities with a lot of love and very little money. But not all captive-wolf owners have conservation foremost in mind. Some are motivated by commerce, or by a difficult-to-pin-down yearning to possess "wildness." It raises uncomfortable questions: At what point does kindness to animals morph into exploitation? What are the appropriate boundaries between humans and wolves? And why do we insist on testing the limits of those boundaries?

Prior to the passage of the 1973 federal Endangered Species Act, which protected wild wolves beginning that year, people openly stole wolf pups from dens to supply the fur industry and zoos. Over the years, captive breeding has produced gray wolves and wolf-dog hybrids for the fur and pet trades, Hollywood, wildlife parks, and research and public education centers. There are even established genetic lines prized by private wolf and wolf-dog breeders.