Wolves as pets and working animals
Some wildlife centers housing captive wolves prohibit handlers from entering wolf enclosures if they happen to have a cold or other vulnerability which the wolves can detect. Captive wolves are generally shy and avoid eye contact with humans other than their owner, as well as not listening to any commands made by any other humans. They usually vacate rooms or hide when a new person enters the establishment. Even seemingly friendly wolves need to be treated with caution, as captive wolves tend to view and treat people as other wolves, and will thus bite or dominate people in the same situation in which they would other wolves. Ordinary pet food is inadequate, as an adult wolf needs 1–2.5 kg (2–5 lbs) of meat daily along with bones, skin and fur to meet its nutritional requirements. Wolves may defend their food against people, and react violently to people trying to remove it. The exercise needs of a wolf exceed the average dog's demand. Because of this, captive wolves typically do not cope well in urban areas. Due to their talent at observational learning, adult captive wolves can quickly work out how to escape confinement, and require constant reinforcement by caretakers or owners, which makes raising wolves difficult for people who raise their pets in an even, rather than subordinate, environment.
Wolf
It was once thought that dogs and gray wolves did not voluntarily interbreed in the wild, though they can produce fertile wolf-dog offspring. In 2010, a study of 74 Italian wolf male lineages found that 5 of them originated from dog ancestry, indicating that female wolves will breed with stray male dogs in the wild. In North America, black colored wolves acquired their coloration from wolf-dog hybridization, which occurred 10,000–15,000 years ago. Like pure wolves, hybrids breed once annually, though their mating season occurs three months earlier, with pups mostly being born in the winter period, thus lessening their chances of survival. However, one genetic study undertaken in the Caucasus Mountains showed that as many as 10% of dogs in the area, including livestock guardian dogs, are first generation hybrids. The captive breeding of wolf-dog hybrids has proliferated in the United States, where there is an estimated population of 300,000.