Wolf-dog hybrid

A wolf-dog hybrid (also called a wolf hybrid or wolfdog) is a canid hybrid resulting from the mating of a wolf (Canis lupus) and a dog (Canis lupus familiaris). The term "wolfdog" is preferred by most wolfdog proponents and breeders since the domestic dog was recently taxonomically recategorized as a subspecies of wolf. Professional organizations such as the American Veterinary Medical Association and government agencies such as the United States Department of Agriculture refer to the animals as wolf-dog hybrids.[1] Rescue organizations consider any animal with wolf heritage within the last five generations to be a wolfdog, including some established wolfdog breeds.[2]

In 1998, the USDA estimated an approximate population of 300,000 wolfdogs in the United States (the highest of any country world-wide), with some other sources giving a population possibly as high as 500,000.[1] In first generation hybrids, gray wolves are most often crossed with wolf-like dogs (such as German Shepherd Dogs, Siberian Huskies, and Alaskan Malamutes) for an appearance most appealing to owners desiring to own an exotic pet.[3] Since wolf hybrids are genetic mixtures of wolves and dogs, their physical and behaviorial characteristics cannot be predicted with any certainty.[1]

[edit] Origins Evidence for prehistoric domesticated wolfdogs in the Americas dates back at least 10,000 years[4] while fossil evidence in Europe points to their use in hunting mammoths.[5] Noted historic cases (such as the Cevennes, France wolf-attack incidents of 1764-1767) of large wolves that were abnormally aggressive toward humans, may be attributable to wolf-dog mating.[1] In terms of intentional breeding efforts, the first documented wolfdog breed, the Saarlooswolfhond, did not begin to be developed until the 1920's. Hybrids were used as experimental attack dogs in South Africa under apartheid.[6]

[edit] Breed-specific legislation The wolfdog hybrid has been the center of much controversy for much of its history, and most breed-specific legislation is either the result of the animal's perceived danger or a categorization as protected native wildlife.[7] The Humane Society of the United States, the RSPCA, local Canadian Humane Societies, the National Canine Defense League and the Wolf Specialist Group of the IUCN Species Survival Commission consider wolfdogs to be wild animals and therefore unsuitable as pets, and support an international ban on the private possession, breeding and sales of wolf-dog hybrids.[8] [9] [10] According to the National Wolfdog Alliance, 40 U.S. states effectively forbid the ownership, breeding and importation of wolfdogs, while others impose some form of regulation upon ownership.[11] Most European nations, as well as many U.S. states and municipalities, also either outlaw the animal entirely or put restrictions on ownership.[12][13].

[edit] Wolf-dog hybrids and threatened wolf populations Two captured hybrids from Germany (both born and raised in the wild) with clear German shepherd ancestryHybridization in the wild usually occurs near human habitations where wolf density is low and dogs are common.[14] However, there were several reported cases of wolf-dogs in areas with normal wolf densities in the former Soviet Union. [15] In Europe, unintentional matings of dogs and wild wolves has been confirmed in some populations through genetic testing. As the survival of some Continental European wolf packs is severely threatened, scientists fear that the creation of wolf-dog hybrid populations in the wild is a threat to the continued existence of European wolf populations.[16] However, extensive wolf-dog hybridization is not supported by morphological evidence, and analyses of mtDNA sequences have revealed that such matings are rare.[14] However, since mtDNA is mainly maternally inherited and most cases of hybridization in the wild seem to occur between a female wolf and a male domestic dog, these results may not be reliable.

[edit] Description The physical characteristics of an animal created by breeding a wolf to a dog are not predictable, similar to that of mixed-breed dogs. Genetic research shows that wolf and dog populations initially diverged approximately 10,000 years ago and have interbred only occasionally since; thus imbuing the dissimilarity between dogs and wolves in behavior and appearance.[17] In many cases the resulting adult wolfdog may be larger than either of its parents due to the genetic phenomenon of heterosis (known to laypersons as hybrid vigor).[1] Hybrids display a wide variety of appearances, ranging from a resemblance to dogs without wolf blood to animals that are often mistaken for full-blooded wolves. A lengthy study by DEFRA and the RSPCA found several examples of misrepresentation by breeders and indeterminate levels of actual wolf pedigree in many animals sold as wolfdogs. The report noted that uneducated citizens misidentify dogs with wolf-like appearance as wolfdogs.[18] In some cases, the presence of dewclaws is considered a useful, but not absolute indicator of dog gene contamination in wild wolves. Dewclaws are the vestigial fifth toes of the hind legs common in domestic dogs but thought absent from pure wolves, which only have four hind toes.[16] Observations on wild wolf hybrids in the former Soviet Union indicate that wolf hybrids in a wild state may form larger packs than pure wolves, and have greater endurance when chasing prey.[19] High content hybrids typically have longer canine teeth than dogs of comparable size, with some officers in the South African Defence Force commenting that the animals are capable of biting through the toughest padding "like a knife through butter".[6]

[edit] Health Wolf-dog hybrids are generally said to be naturally healthy animals, and are affected by less inherited diseases than most breeds of dog. Wolfdogs are usually healthier than either parent due to heterosis.[1] Some of the established breeds of wolfdog that exist today were bred specifically to improve the health and vigor of working dogs.

There is some controversy over the effectiveness of the standard dog/cat rabies vaccine on a wolfdog. The USDA has not to date approved any rabies vaccine for use in wolf-dog hybrids, though they do recommend an extra-label use of the vaccine.[20] Wolfdog owners and breeders purport that the lack of official approval is a political move to prevent condoning wolfdog ownership.[21]

[edit] Temperament and behaviour The SaarlooswolfhondWolf-dog hybrids are a mixture of genetic traits, which results in less predictable behavior patterns compared to either the wolf or dog.[1] This is not to say that the behavior of any specific hybrid is erratic. It would, however, be unlikely that someone unfamiliar with an individual animal would be able to predict that animal's behavior with reasonable certainty. The adult behavior of hybrid pups also cannot be predicted with comparable certainty to dog pups, even in third-generation pups produced by wolfdog matings with dogs or from the behavior of the parent animals.[1] Thus, though the behavior of an individual wolf hybrid may be predictable, the behavior of the type as a whole is not.[1]

According to the CDC and the Humane Society of the United States, the wolfdog ranks sixth in the number of dog attack fatalities in the U.S.; with 14 hybrid-related fatalities between 1979 and 1998 in the United States.[22] [23] In 2000, DEFRA and the Royal Society for the Prevention of Cruelty to Animals released a lengthy study that attributed much of the reported aggressiveness of wolfdogs to the characteristics of the breeds of dogs the wolves are bred with. With both wolves' and dog's social habits revolving around a pack structure, wolfdogs may not show the dog's natural acceptance of humans as the dominant pack members, possibly resulting in physical confrontations.[1] Some purport that attacks may not even be caused by typical behavior patterns of aggression and dominance present in either parent species, but instead may be related to predatory instincts, as the majority of attacks involve small children.[1] Between 1981 and 1999, there have been 38 severe attacks and 13 fatalities caused by wolf hybrids in North America, with all victims being children.[24] An officer in the South African Defence Force once commented that it was very difficult to dissuade wolf hybrids from pressing an assault once an attack was initiated.[6]

Most wolf and wolfdog rescue organizations maintain wolfdogs retain many of the traits and requirements of their wild relatives and therefore may be inappropriate as domestic pets.[25][26] The view that aggressive characteristics are inherently a part of wolfdog temperament has been contested in recent years by wolfdog breeders and other advocates of wolfdogs as pets.[27][28] Proponents of wolfdogs as pets say that the animals are naturally timid and fearful of humans, but that with proper training and responsible ownership wolfdogs can become good pets.[29] [30] Even in cases of wolfdogs displaying consistently dog-like behavior, they often retain the wolf's natural curiosity; driving them to dig ferociously, chew up household items such as furniture and display extreme difficulty in housebreaking.[1] [31]

[edit] Breeds Today, four breeds of dog exist that utilized a significant amount of recent wolf-dog hybridization in their creation. All of the breeds were the result of intentional crosses with German Shepherd Dogs, and have distinguishing characteristics of appearance that may reflect the varying subspecies of wolf that contributed to their foundation stock. The intention in creating the breeds was manifold; ranging from the desire for a recognizable companion wolfdog, to military working dogs. The eldest breed, the Saarlooswolfhond, traces its origins to the efforts of a Dutch breeder in 1921. This first attempt at sustained wolf-dog crossing was to improve Shepherd breeding stock and prevent canine distemper. Though this effort failed, today the FCI and the Dutch Kennel Club both recognize the breed. In the 1950's, the Kunming Wolf-dog was created, as a working military dog. In the 1950's the Czechoslovakian Vlcak was also created to work on border patrol in the countries now known as Slovakia and the Czech Republic. It is recognized by the Foundation Stock Service of the American Kennel Club AKC, the United Kennel Club UKC, and the FCI, and today is used in agility, obedience, search and rescue, police work, therapy work, and herding in Europe and the United States.