They can be long-legged and yellow-eyed like their wolf relatives or resemble affection-seeking domestic dogs.
Experts say looks can be deceiving when it comes to wolf dogs, hybrid canines that are part wolf and part dog.Two recent attacks by wolf dogs in Colorado, one fatal, has raised the question: Why would anyone want a pet that is part wild animal?
Many people do. On any given day, Denver-area newspapers advertise wolf hybrid pups for $150 to $500, with the cost tied to the amount of wild wolf a pup pos-sesses.
Kent Weber, director and founder of Mission Wolf, estimates there are more than half a million wolf dogs in the United States, although other estimates run as high as 1 million. In Colorado, there are about 50,000 wolf dog hybrids, he said.
"Some folks want unique pets. They want something that is different," said Bob Rohde, executive director of Denver Dumb Friends League, a private animal welfare organization that each year cares for and places for adoption 20,000 abandoned dogs, cats and other animals.
Each year, the league euthanizes about 10 wolf dogs, refusing to place them in homes because they are considered unpredictable, Rohde said.
Others are sent to Mission Wolf, a refuge for wild wolves and wolf hybrids about 22 miles southeast of Westcliffe. There they will spend their days in confinement without reproducing.
Kent Weber, director and founder of Mission Wolf, said people who buy hybrids never can be sure what they are getting. Their new pet could be anything from a full-blooded wolf to a wolfish-looking dog.
Hybrid opponents say owners are creating dangerous pets by crossbreeding wolves - which fear and avoid people - and companionship-loving dogs. The result can be a creature with the cunning and instincts of a wild animal that is unafraid of people.
"That's a dangerous combination," Rohde said.
Weber said most will end up dead before they are 2 years old because few people can offer wolf dogs the space and intensive care they need.
Nationally, a handful of deaths have been linked to wolf hybrids. Ten people, mostly children and toddlers, were killed between 1986 and 1994, according to the Humane Society.
Last month, a wolf dog mauled a 10-year-old Colorado Springs boy, who required 28 stitches in his scalp and suffered 30 puncture wounds in his right arm. The boy had unchained the wolf hybrid, which belonged to his uncle but was being kept by his father.
In December, two boys, ages 10 and 13, watched in horror as two wolf hybrids killed their mother. Debbie K. Edmonds, 39, of the Colorado Springs area was trying to return the animals to their pen.
Coroner David Bowerman said the woman suffered "massive blunt trauma" to her upper body - injuries far more severe than those inflicted by domestic dogs.
"These injuries are different than what I've seen from canines, such as Malamutes," Bowerman said. "There is actually some tearing of tissues. These wolves did ingest the tissue."
Wolves should never be crossbred with dogs, said Rob Edward, outreach coordinator for the Boulder-based Sinapu, an organization trying to reintroduce the grey wolf to Colorado.
"What you have is a tremendously powerful animal with wild instincts that does not fear humans because they are crossbred with more domesticated stock," Edward said. "That can translate into something as graphically horrifying as what happened to that woman in Colorado Springs."
Sinapu, Edward said, is "righting a huge biological wrong" by supporting the reintroduction of the grey wolf. Colorado's last wild wolf was killed in the South San Juan Wilderness in 1945, following a 70-year campaign by farmers and ranchers to eliminate them.
Those who support reintroduction of the wolf say bad publicity surrounding wolf-dog attacks has tarnished the wild wolf's image. Edward said fewer than one in 10,000 livestock deaths can be attributed to wolves in areas where wolves and livestock live together.
Wolf-dog owners who later realize they cannot care for the hybrids and cannot find anyone to take them often will turn them into the wild, mistakenly believing they can survive on their own.
"But they haven't been taught to hunt, so very few actually do survive," Edward said. "And that's cruel."
If wolf dogs are released into the wild and they do survive, they might again crossbreed with wild wolves that come into Colorado naturally or are reintroduced.
"Then what you have is a genetically unpure gene pool, and it's very important that we keep the wild wolf gene pool as pure as possible (to fend off disease)," Edward said. "We want them (wolves) to have the best chance of survival so they can flourish."
Dorm rooms, high-rise apartments and small cages are some of the unlikely places owners keep wolf hybrids.
"Sadly, people are making so much on (breeding) them there's not much we can do until they start regulating them," Weber said.
Mission Wolf offers sanctuary to 49 wolves and wolf hybrids on 73 acres.
Weber said his refuge has turned away 4,000 homeless wolves and hybrids for lack of space and funding. The animals come from many sources, including Hollywood film projects.
Weber believes the popularity of wolf dogs can be traced to society's need to reconnect with wildlife and the Wild West.
"The wolf is the symbol of the wilderness," he said.
Keeping wolves or wolf hybrids is illegal in Wyoming, and other states have laws based on the percentage of wolf in hybrids, said Suzanne Laverty, education director for the Wolf Education Research Center in Boise, whose policy is that wolves belong in the wild.
Colorado has no regulations on keeping or breeding wolf dogs. They are part wild animal, so the state Department of Health cannot regulate them. They are part domestic, ruling out state wildlife regulation.
They are considered illegal in Denver, said Dr. Eugene Pei, public health veterinarian for the city, who said he runs across two or three a year. It's not always easy to distinguish between a wolf hybrid and a dog with wolfish physical characteristics, he said.
"A wolf will stick his mouth around your head (in greeting). I don't know many dogs that do that," Pei said. "People who are unfamiliar with that will jerk away and get their face ripped off."