|Other names||Wolf–dog hybrid
|Domestic dog (Canis lupus familiaris)|
A wolfdog (also called a wolf–dog hybrid or wolf hybrid) is a canid hybrid resulting from the hybridization of a domestic dog (Canis lupus familiaris) to one of four other Canis sub-species, the gray (Canis lupus), eastern timber (Canis lycaon), red (Canis rufus), and Ethiopian wolves (Canis simensis).
- 1 Description
- 2 Varieties
- 3 History
- 3.1 Prehistoric wolfdogs
- 3.2 Teotihuacan wolfdogs
- 3.3 North American gray wolf-domestic dog hybrids
- 3.4 British wolfdogs
- 3.5 Documented breeding
- 3.6 Livestock guardian dogs
- 3.7 New World black wolves
- 3.8 Random-bred wolfdogs
- 3.9 Breed-specific legislation
- 3.10 Wolfdogs in the wild
- 4 Description
- 5 Health
- 6 Temperament and behavior
- 7 Further reading
- 8 See also
- 9 References
- 10 External links
Intra-hybridization between dogs and other subspecies of gray wolves are the most common wolfdogs since dogs and gray wolves are considered the same species, are genetically very close, and have shared vast portions of their ranges for millennia. Such hybridization in the wild have been detected in many populations scattered throughout Europe and North America, usually occurring in areas where wolf populations have declined from human impacts and persecutions. At the same time, hybrids are also often bred in captivity for various purposes. Inter-hybridization of dogs and two other North American wolf species have also occurred historically in the wild, although it is often difficult for biologists to discriminate the dog genes in the eastern timber and red wolves from the gray wolf genes also present in these wolf species due to their historical overlaps with North American gray wolves as well as with coyotes, both of which have introgressed into the eastern timber and red wolf gene pools. At the same time, because many isolated populations of the three wolf species in North America have also mixed with coyotes in the wild, it has been speculated by some biologists that some of the coywolf hybrids in the northeastern third of the continent may also have both coydogs and wolfdogs in their gene pool. Hybrids between dogs and Ethiopian wolves discovered in the Ethiopian Highlands likely originated from past interactions between free-roaming feral dogs and Ethiopian wolves living in isolated areas.
The term "wolfdog" is preferred by most of the animals' proponents and breeders because the domestic dog was taxonomically recategorized in 1993 as a subspecies of Canis lupus. The American Veterinary Medical Association and the United States Department of Agriculture refer to the animals as wolf–dog hybrids.
One of the issues that many researchers and wolfdog communities are faced with is identifying wolfdogs from pure dogs and any of the wolf species mixed into the hybrid. The most common method used by various wolfdog communities is phenotyping, a method that involves observing the animal's physical features. This method is often favoured for many in determining the degree of wolf and northern spitz-type dog that is in a hybrid. However, a lot of criticisms have been made by opponents within some communities who tend to point out that phenotyping cannot always determine the wolf-contents accurately. Another challenge involves determining exactly the domestic breeds and wolf subspecies involved in the admixture due to the fact that dogs are known to come in various breeds while gray wolves in turn come in various subspecies with many different regional ecotypes hence have different physical features depending on the subspecies used in the breeding. Although wolves are often mixed with spitz types such as Siberian Huskies, Alaskan Malamutes, and German Shepherds, hybrids between wolves to non-Spitz type dogs such as Poodles, Pitbulls, and Great Pyrenees also exist, the latter hybrids often having less lupine features.
In 2010, experts announced that they had found the remains of many wolf-dogs that had been kept by the warrior class of the Teotihuacan civilization in Mexico's central valley about two thousand years ago, and that, in light of this evidence, certain animals commonly depicted in the art of that culture, which had been thought to be strange dogs or coyotes, were likely instead wolf-dogs.[clarification needed]
North American gray wolf-domestic dog hybrids
In 1998, the USDA estimated an approximate population of 300,000 wolfdogs in the United States (the highest of any country worldwide), with some other sources giving a population possibly as high as 500,000. In first-generation hybrids, gray wolves are most often crossed with wolf-like dogs (such as German Shepherds, Siberian Huskies, and Alaskan Malamutes) for an appearance most appealing to owners desiring an exotic pet.
The first record of wolfdog breeding in Great Britain comes from the year 1766 when what is thought was a male wolf mated with a dog identified in the language of the day as a "Pomeranian", although it may have differed from the modern Pomeranian breed. The union resulted in a litter of nine pups. Wolfdogs were occasionally purchased by English noblemen, who viewed them as a scientific curiosity. Wolfdogs were popular exhibits in British menageries and zoos.
Currently, at least seven breeds of dog exist that acknowledge a significant amount of recent wolf-dog hybridization in their creation. One breed is the "wolamute", aka "malawolf", a cross between an Alaskan Malamute and a timber wolf. Four breeds were the result of intentional crosses with German Shepherds (one of the original intentionally bred wolf-dog crossbreeds), and have distinguishing characteristics of appearance that may reflect the varying subspecies of wolf that contributed to their foundation stock. Other, more unusual crosses have occurred; recent experiments in Germany were conducted in the crossing of wolves and Poodles. The intent behind creating the breeds has ranged widely from simply the desire for a recognizable companion high-content wolfdog to professional military working dogs. Typical examples include:
Among the dogs used in the development of the German Shepherd, at least four were either wolfdogs or partly descended from wolfdogs. In 1899, Max von Stephanitz, an ex-cavalry captain and former student of the Berlin Veterinary College, was attending a dog show when he was shown a dog named Hektor Linksrhein, who was allegedly one-quarter wolf. Renamed Horand von Grafrath, the dog and his progeny were used to create the German Shepherd. Horand became the centre-point of the breeding programs and was bred with dogs belonging to other society members that displayed desirable traits. Although fathering many pups, Horand's most successful was Hektor von Schwaben. Hektor was line bred with another of Horand's offspring and produced Beowulf, who later fathered a total of eighty-four pups, mostly through being line bred with Hektor's other offspring. In the original German Shepherd studbook, Zuchtbuch für Deutsche Schäferhunde (SZ), within the two pages of entries from SZ No. 41 to SZ No. 76, there are four wolf crosses. This is the first documented use of pure wolf genes to create a domestic dog breed, the German Shepherd, which is historically thought to be the first documented intentionally-bred wolfdog.
The Saarloos wolfdog
The Saarloos wolfdog traces its origins to the efforts of a Dutch breeder in 1935. Leendert Saarloos who crossbred a German Shepherd male to a female Mackenzie Valley wolf (Canis lupus occidentalis). He aimed for an improved version of the German Shepherd that would be immune to canine distemper. He succeeded insofar as the Saarloos Wolfdog known today is a strong, imposing breed that has kept its wolf-like characteristics; it is cautious, reserved, and lacks the ferocity to attack. It is not, however, the dog that Leendert Saarloos hoped to get, as nearly all the first-generation hybrids succumbed to distemper. Until Leendert Saarloos died in 1969, he was in full control over the breeding of his "European wolfdog". The Dutch Kennel Club recognized the breed in 1975. To honor its creator they changed the name to "Saarloos Wolfdog". In 1981 the breed was recognized by the Fédération Cynologique Internationale (FCI). Some Saarloos Wolfdogs have been trained as guide dogs for the blind and as rescue dogs.
The Czechoslovakian Wolfdog
In the 1950s, the Czechoslovakian Wolfdog 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, the United Kennel Club, and the Fédération Cynologique Internationale, and today is used in agility, obedience, search and rescue, police work, therapy work, and herding in Europe and the United States.
The Lupo Italiano
Currently, the breed is protected by presidential decree stipulating that this 'State' dog can not be commercialized nor bred outside the officially recognized agency, the Etli, Ente Tutela del Lupo Italiano (Agency for the protection of the Lupo Italiano).
The Hierran Wolfdog
The Hierran Wolfdog originated in the Island of El Hierro, in the Canary Islands (Spain). Although its origin is still uncertain, in the 15th century dogs similar to wolves already existed in the Canary Islands, called cancha by Aboriginals. At the arrival of the Spanish conquest, the chaplains accompanying the Conquistadors wrote about the presence of "wild dogs like wolves, but they are small". It is known that the Hierran Wolfdog has been present in the last two centuries and could have probably come up with the first settlers of the island. This species of dog has achieved its preference among the shepherds of the island.
The Kunming wolfdog
The Kunming wolfdog (Chinese: 昆明狼狗; pinyin: Kūnmíng lánggǒu), also commonly known as the Kunming dog (Chinese: 昆明犬; pinyin: Kūnmíng quǎn) is an established breed of wolfdog originated in China. Unlike most other wolfdog crosses, Kunming dogs are suitable as guard dogs and working dogs due to their German Shepherd ancestry. They have been trained as military assistant dogs to perform a variety of tasks such as detecting mines. Some are also trained to be fire dogs and rescue dogs. Today they are commonly kept as family companions by many pet owners in China.
Livestock guardian dogs
A 2014 study found that 20% of wolves and 37% of dogs shared the same mitochondrial haplotypes in Georgia. More than 13% of the studied wolves had detectable dog ancestry and more than 10% of the dogs had detectable wolf ancestry. The results of the study suggest that wolf-dog hybridization is a common event in the areas where large livestock guardian dogs are held in a traditional way, and that gene flow between dogs and gray wolves was an important force influencing gene pool of dogs for millennia since early domestication events.
New World black wolves
Genetic research from the Stanford University School of Medicine and the University of California, Los Angeles revealed that wolves with black pelts owe their distinctive coloration to a mutation that entered the wolf population through wolf-dog hybridisation. Adolph Murie was among the first wolf biologists to speculate that the wide color variation in wolves was due to interbreeding with dogs;
"I suppose that some of the variability exhibited in these wolves could have resulted from crossings in the wild with dogs. Such crosses in the wild have been reported and the wolf in captivity crosses readily with dogs. Some years ago at Circle, Alaska, a wolf hung around the settlement for some time and some of the dogs were seen with it. The people thought that the wolf was a female attracted to the dogs during the breeding period. However, considerable variability is probably inherent in the species, enough perhaps to account for the variations noted in the park and in skins examined. The amount of crossing with dogs has probably not been sufficient to alter much the genetic composition of the wolf population."— The Wolves of Mount McKinley by Adolph Murie, 1944, ISBN 0-295-96203-8, 978-0-295-96203-0, 238 pages
In 2008, Dr. Gregory S. Barsh, a professor of genetics and pediatrics at the Stanford University School of Medicine used molecular genetic techniques to analyze DNA sequences from 150 wolves, half of them black, in Yellowstone National Park, which covers parts of Wyoming, Montana and Idaho. It was discovered that a gene mutation responsible for the protein beta-defensin 3, known as the K locus, is responsible for the black coat color in dogs. After finding that the same mutation was responsible for black wolves in North America and the Italian Apennines, he set out to discover the origin of the mutation. Barsh and his colleagues concluded that the mutation arose in dogs 13,000 to 120,000 years ago, with a preferred date of 47,000 years ago after comparing large sections of wolf, dog, and coyote genomes. At the University of California, Los Angeles, Robert K. Wayne, a canine evolutionary biologist, stated that he believed that dogs were the first to have the mutation. He further stated that even if it originally arose in Eurasian wolves, it was passed on to dogs who, soon after their arrival, brought it to the New World and then passed it to wolves and coyotes. Black wolves with recent dog ancestry tend to retain black pigment longer as they age.
Cases of accidental breeding of wolfdogs are known (though this is very rare), where a domestic dog female in oestrus strays and is mated by a male wild wolf.
The wolfdog hybrid has been the center of controversy for much of its history, and most breed-specific legislation is either the result of the animal's perceived danger or its categorization as protected native wildlife. The Humane Society of the United States, the RSPCA, Ottawa Humane Society, the Dogs Trust 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 sale of wolfdogs.
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. In Canada, the provinces of Alberta, Manitoba, Newfoundland, and Prince Edward Island prohibit wolfdogs as pets. Most European nations have either outlawed the animal entirely or put restrictions on ownership. Wolfdogs were among the breeds banned from the U.S. Marine Corps base at Camp Pendleton and elsewhere after a fatal dog attack by a Pitbull on a child.
Wolfdogs in the wild
Hybridization in the wild usually occurs near human habitations where wolf density is low and dogs are common. However, there were several reported cases of wolfdogs in areas with normal wolf densities in the former Soviet Union. Wild wolfdogs were occasionally hunted by European aristocracy, and were termed lycisca to distinguish them from common wolves. Noted historic cases (such as the Beast of Gévaudan) of large wolves that were abnormally aggressive toward humans, may be attributable to wolf-dog mating. In Europe, unintentional mating of dogs and wild wolves have 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 wolfdog populations in the wild is a threat to the continued existence of European wolf populations. However, extensive wolf–dog hybridization is not supported by morphological evidence, and analyses of mtDNA sequences have revealed that such mating are rare. In 1997, during the Mexican Wolf Arizona Reintroduction, controversy arose when a captive pack at Carlsbad designated for release was found to be largely composed of wolfdogs by Roy McBride, who had captured many wolves for the recovery programme in the 1970s. Though staff initially argued that the animals' odd appearance was due to captivity and diet, it was later decided to euthanise them.
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 14,000 years ago and have interbred only occasionally since, accounting for the dissimilarity between dogs and wolves in behavior and appearance. In many cases the resulting adult wolfdog may be larger than either of its parents due to the genetic phenomenon of heterosis (commonly known as hybrid vigor). Breeding experiments in Germany with Poodles and wolves, and later on with the resulting wolfdogs showed unrestricted fertility, mating via free choice and no significant problems of communication (even after a few generations). The offspring of poodles with either coyotes and jackals however all showed a decrease in fertility, significant communication problems, and an increase of genetic diseases after three generations of interbreeding between the hybrids. The researchers therefore concluded that domestic dogs and wolves are the same species.
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. Wolfdogs tend to have somewhat smaller heads than pure wolves, with larger, pointier ears that lack the dense fur commonly seen in those of wolves. Fur markings also tend to be very distinctive and not well blended. Black coloured hybrids tend to retain black pigment longer as they age, compared to black wolves. In some cases, the presence of dewclaws on the hind feet is considered a useful, but not absolute indicator of dog gene contamination in wild wolves. Dewclaws are the vestigial first toes, which are common on the hind legs of domestic dogs but thought absent from pure wolves, which only have four hind toes. 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. High wolf-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". Their sense of smell apparently rivals that of most established scenthounds. Tests undertaken in the Perm Institute of Interior Forces in Russia demonstrated that high wolf-content hybrids took 15–20 seconds to track down a target in training sessions, whereas ordinary police dogs took three to four minutes.
Wolf-dog hybrids are generally said to be naturally healthy animals, and are affected by fewer inherited diseases than most breeds of dog. Wolfdogs are usually healthier than either parent due to heterosis. 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 off-label use of the vaccine. Wolfdog owners and breeders purport that the lack of official approval is a political move to prevent condoning wolfdog ownership.
Temperament and behavior
Wolf-dog hybrids are a mixture of genetic traits, which results in less predictable behavior patterns compared to either the wolf or dog. The adult behavior of hybrid pups also cannot be predicted with comparable certainty to dog pups, even in third-generation pups produced by wolfdog mating with dogs or from the behavior of the parent animals. Thus, though the behavior of a single individual wolf hybrid may be predictable, the behavior of the type as a whole is not. The majority of high wolf-content hybrids are very curious and are generally no more destructive than any other curious or active dogs.
This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)(Learn how and when to remove this template message)
A wolf’s behavior is typically more socially shy and timid toward humans than that of a dog. Due to the variability inherent to their hybridization, whether a wolf–dog cross should be considered more dangerous than a dog depends on behavior specific to the individual alone rather than to wolfdogs as a group.
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. Proponents of wolfdogs as pets say that the higher wolf-content animals are naturally timid and fearful of humans, but that with proper human association, training, and responsible ownership nearly all wolfdogs can become good companions, especially if their association and training begins at an early age. Even in cases of wolfdogs displaying consistently dog-like behavior, they may occasionally retain some wolf-like behavior such as digging dens, chewing up household items, climbing fences, and, to varying degrees, displaying some difficulty in housebreaking in relation to how high their wolf genetic content is. Low wolf-content wolfdogs rarely have these problems any more strongly or significantly than any other large-breed dog.
- Living with Wolfdogs by Nicole Wilde
- Wolfdogs A-Z: Behavior, Training & More by Nicole Wilde
- The Wolf Hybrid by Dorothy Prendergast
- Above Reproach: A Guide for Wolf Hybrid Owners by Dorothy Prendergast
- Between Dog and Wolf: Understanding the Connection and Confusion by Jessica Addams and Andrew Miller
|Wikimedia Commons has media related to Wolf-dog hybrid.|
- Black wolf
- Domesticated silver fox
- Domestication of the dog
- Interbreeding of dingoes with other domestic dogs
- Jackal-Dog Hybrid
- Wolves as pets and working animals
- "Multilocus Detection of Wolf x Dog Hybridization in Italy, and Guidelines for Marker Selection". PLoS ONE. 9: e86409. doi:10.1371/journal.pone.0086409. Retrieved 2016-04-06.
- "Hybridization between Wolves and Dogs". Conservation Biology. 13: 195–198. 2001-12-24. doi:10.1046/j.1523-1739.1999.97425.x. Retrieved 2016-04-06.
- "Great Lakes-Boreal Wolf". Wolf.nrdpfc.ca. Retrieved 2016-04-06.
- "Hybridization among Three Native North American Canis Species in a Region of Natural Sympatry". Plos One. 2008-10-08. Retrieved 2016-04-06.
- "Mysteries That Howl and Hunt". The New York Times. Retrieved 2016-04-06.
- Gottelli, D; Sillero-Zubiri, C; Applebaum, GD; et al. (2015-09-28). "Molecular genetics of the most endangered canid: the Ethiopian wolf Canis simensis.". Mol. Ecol. 3: 301–12. PMID 7921357. doi:10.1111/j.1365-294X.1994.tb00070.x.
- "The Wolf-Dog Hybrid: An Overview of a Controversial Animal". Animal Welfare Information Center Newsletter. 2000. Retrieved 2008-05-17.
- "Content and Phenotyping - Wolf-dog Education". Texx-wolf-tails.com. Retrieved 2016-04-06.
- "Comparison Study Between Wolves and Poodles". Dogpsychology.dog-articles.net. Retrieved 2016-04-06.
- "Oreo | Mission: Wolf". Missionwolf.org. 2009-04-19. Retrieved 2016-04-06.
- Walker, D. N.; Frison, G. C. (1982). "Studies on Amerindian Dogs 3: Prehistoric Wolf/Dog Hybrids from the Northwestern Plains". Journal of Archaeological Science. 9 (2): 125–172. doi:10.1016/0305-4403(82)90047-4.
- Schwartz, M. (1997). A History of Dogs in the Early Americas. Yale U. Pr. ISBN 0-300-07519-7.
- "Chap 1" (PDF). Retrieved 2014-02-14.
- "The Keeping of Wolf-Hybrids in Great Britain" (PDF). RSPCA. Retrieved 2008-06-11.
- Doris Feddersen-Petersen, Hundepsychologie, 4. Auflage, 2004, Franck-Kosmos-Verlag 2004
- Stevens, p.11
- "Progency list for V Beowulf". Pedigree Database. Retrieved 2008-08-14.
- "United Kennel Club: Saarloosewolfdog". Ukcdogs.com. 2006-07-01. Retrieved 2016-04-06.
- "Photos and characteristics of the "Lupo italiano"". Menandpets.com. Retrieved 2013-12-16.
- "Lupo italiano". Italia-online.co.uk. Retrieved 2014-03-04.
- "Lupo Italiano (Italian Lupo)".
- "BC Museum: Herding Dogs of Western Europe: Spain". Bordercolliemuseum.org. 2014-01-03. Retrieved 2016-04-06.
- "昆明犬 - 动物百科". Chinabaike.com. 2007-10-29. Retrieved 2014-03-04.
- "Wolfdogs - Snowdog". Snowdog-northerninuit.webs.com. Retrieved 2012-02-21.
- "昆明犬（图片）保留了早期工作德国牧羊犬基因但退化已令人担忧-军犬网—军犬德国牧羊犬". Armydog.com.cn. 2009-02-01. Retrieved 2014-03-04.
- Kopaliani, Natia; Shakarashvili, Maia; Gurielidze, Zurab; Qurkhuli, Tamar; Tarkhnishvili, David (12 March 2014). "Gene Flow between Wolf and Shepherd Dog Populations in Georgia (Caucasus)". Heredity. PMID 24622972. doi:10.1093/jhered/esu014.
- "New World Wolves and Coyotes Owe Debt to Dogs". The New York Times. Retrieved 2014-03-04.
- "Adolph Murie speculated on dog-wolf hybridization as the source of unusual color". Retrieverman.wordpress.com. 2013-08-27. Retrieved 2013-12-16.
- "Black Wolf Mystery Solved". Redorbit.com. 2009-02-06. Retrieved 2013-12-16.
- Thomas H. Maugh II (2009-02-07). "The big black wolf is a legacy from dogs, study finds". Latimes.com. Retrieved 2013-12-16.
- "The Wolf Hybrid: Identification". Monty Sloan. Wolf Park. Archived from the original on 2007-03-03. Retrieved 2007-05-11.
-  Archived December 15, 2006, at the Wayback Machine.
- "Ottawa Humane". Ottawahumane.ca. Retrieved 2013-12-16.
-  Archived September 30, 2007, at the Wayback Machine.
- "NWA". Wolfdogalliance.org. Retrieved 2013-12-16.
- Bruch, Robert H. (2007). The Wolf Almanac. The Lyons Press. p. 185. ISBN 978-1-59921-069-8.
- "National Wolf Dog Alliance". Wolfdogalliance.org. Retrieved 2013-12-16.
- "Marine Corps bans pit bulls, Rottweilers at Camp Pendleton, other bases". L.A. Now. The Los Angeles Times. October 9, 2009.
- L. David Mech; Luigi Boitani (2001). Wolves: Behaviour, Ecology and Conservation. p. 448. ISBN 0-226-51696-2.
- Der Wolf; Prof. Dr. Dmitrij Iwanowitsch Bibikow, Moskau, 2. Auflage; A. Ziemsen Verlag, Wittenberg Lutherstadt, 1990, ISBN 3-7403-0155-4
- Rousseau, Élise (2006). Anthologie du Loup (in French). p. 319. ISBN 2-603-01335-1.
- "Claws reveal wolf survival threat". Paul Rincon. London: BBC online. 2004-04-08. Retrieved 2007-05-11.
-  Archived June 17, 2009, at the Wayback Machine.
- "Vila, C., Savolainen, P., Maldonado, J. E., Amorim, I. R., Rice, J. E., Honeycutt, R. L., et al. (1997). Multiple and ancient origins of the domestic dog. ''Science 276''(5319), 1687-1689. Retrieved December 21, 2006". Science. Sciencemag.org. 276: 1687–1689. 1997-06-13. doi:10.1126/science.276.5319.1687. Retrieved 2013-12-16.
- Graves, Will (2007). Wolves in Russia: Anxiety throughout the ages. p. 222. ISBN 1-55059-332-3.
- Alex MacCormick, ed. (2003), "The Wolf Inside Every Dog", The mammoth book of maneaters, Carroll & Graf Publishers, ISBN 978-0-7867-1170-3
- "Russian police employ wolves for service". English.pravda.ru. 2006-04-25. Retrieved 2013-12-16.
- "RSPCA report on wolfdogs" (PDF). DEFRA. 2013-01-23. Retrieved 2013-12-16.
- "The WolfDog Project QandA". Web.archive.org. 2009-10-27. Archived from the original on October 27, 2009. Retrieved 2013-12-16.
- Derr, Mark (2013-05-21). "Why the Transformation of Wolves to Dogs Remains a Puzzle". Psychology Today. Retrieved 2013-12-16.
- Rick Bohning. "Dog Aggression: A Few Suggestions Of What To Do - Training the Wolf". Chicagonow.com. Retrieved 2013-12-16.
- Goldman, Jason G. "Dogs, But Not Wolves, Use Humans As Tools | The Thoughtful Animal, Scientific American Blog Network". Blogs.scientificamerican.com. Retrieved 2013-12-16.
- "We Didn’t Domesticate Dogs. They Domesticated Us". News.nationalgeographic.co.uk. 2013-03-03. Retrieved 2013-12-16.
- "The Wolf Dunn's Wolfdog FAQ - Question #1". Inetdesign.com. Retrieved 2013-12-16.
- "The Wolf Is At The Door, Inc". Wolf-to-wolfdog.org. Retrieved 2014-03-04.