Man’s best friend, the wolf’s worst enemy? How domestic dogs can threaten Europe’s wolf comeback
Once driven to the brink of extinction in many countries, wolves can now be found in more than 30 European countries. Thanks to legal – though recently reduced – protection under the Bern Convention and the EU’s Habitats Directive, populations are growing in countries such as Italy, Poland and Spain. But conservation success has brought new challenges – most notably interactions with Europe’s exploding dog population.
Dogs, wolves’ genetic cousins, pose two major threats: disease transmission and hybridisation.
Wolves and dogs share over 350 known pathogens – micro-organisms such as viruses, bacteria, fungi and parasites that can cause disease in animals and humans. These include rabies (RABV), canine distemper virus (CDV) and canine parvovirus (CPV), all of which can be spread by direct contact or contaminated environments. Dogs often act as a reservoir for these diseases. Even vaccinated populations can reintroduce infections through illegal animal movements, free-roaming pets or weak enforcement of veterinary laws.
Mass dog vaccination campaigns in the 1990s significantly reduced rabies outbreaks across Europe. However, a recent increase in the unregulated dog trade – often involving falsified documents and unvaccinated animals – has raised concerns again. Although cases of rabid wolves are extremely rare, an infected wolf can travel long distances, potentially spreading the virus and posing a serious risk to both public health and wildlife.
Distemper and parvovirus – highly contagious viral diseases – are a more insidious threat. While often not fatal in dogs, these viruses can have a devastating effect on small, recovering wolf populations. In countries such as Italy and Portugal, genetic analysis has identified domestic dogs as the most likely source of canine distemper virus (CDV) outbreaks in wolves.
When wolves and dogs mate
Hybridisation is a major challenge for wolf conservation. Interbreeding is more likely to occur in areas with large numbers of dogs, particularly where wolf populations are small or stressed. These dogs, often feral or loosely owned in rural areas, remain a persistent management problem in much of Europe. The resulting wolf-dog hybrids are fertile and can breed with wolves, weakening genetic integrity and potentially introducing traits that reduce wolf fitness and survival in the wild.
Unlike many conservation challenges, hybridisation is politically controversial. Definitions vary from country to country, and there is little consensus on how – or even whether – to intervene. Although EU nature legislation allows for the removal of hybrids, enforcement remains uneven. This legal ambiguity undermines coordinated cross-border efforts to protect wolves. In addition to threatening the genetic integrity of the species, hybridisation can also be used by opponents of wolf recovery as a loophole to justify lethal control.
What needs to happen
Experts are calling for a coordinated Europe-wide strategy to reduce the threat dogs pose to wolves.
Main recommendations
|
Conservation can’t stop at protecting wolves. We also need to manage the human dimension – and that includes our relationship with domestic dogs. As Europe navigates this delicate balance between rewilding and human presence, the fate of wolves may depend not only on reduced protection and hunting guns, but also on how we manage our oldest animal companion.
References
Bailey, T. N. et al. (1995) ‘Exposure of wolves to canine parvovirus and distemper on the Kenai National Wildlife Refuge, Kenai Peninsula, Alaska, 1976-1988’, Ecology and conservation of wolves in a changing world, 35, pp. 441-46.
Battilani, M. et al. (2001) ‘Analysis of canine parvovirus sequences from wolves and dogs isolated in Italy’, Journal of General Virology, 82(7), pp. 1555-1560.
Beineke, A. et al. (2015) ‘Cross-species transmission of canine distemper virus—an update’, One health, 1, pp. 49-59.
Bern Convention (1979) Convention on the Conservation of European Wildlife and Natural Habitats. Council of Europe.
Boitani L. (2000) Action plan for the conservation of wolves in Europe (Canis lupus). Brussels: Council of Europe Publishing.
Boitani, L. and Linnell, J. D. (2015) ‘Bringing large mammals back: large carnivores in Europe’, Rewilding European Landscapes, pp. 67-84.
Boitani, L. et al. (2022) ‘Assessment of the conservation status of the Wolf (Canis lupus) in Europe’, Council of Europe Publishing. Available at: https://rm.coe.int/inf45e-2022-wolf-assessment-bern-convention-2791-5979-4182-1-2/1680a7fa47 (Accessed: 1 December 2024).
Cleaveland, S. et al. (2001) ‘Diseases of humans and their domestic mammals: pathogen characteristics, host range and the risk of emergence’, Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 356(1411), pp. 991-999.
Daszak, P. et al. (2000) ‘Emerging infectious diseases of wildlife–threats to biodiversity and human health’, Science, 287(5452), pp. 443-449.
Decaro, N. et al. (2006) ‘First detection of canine parvovirus type 2c in pups with haemorrhagic enteritis in Spain’, Journal of Veterinary Medicine, Series B, 53(10), pp. 468-472.
Di Sabatino, D. et al. (2014) ‘Arctic lineage-canine distemper virus as a cause of death in Apennine wolves (Canis lupus) in Italy’, PLoS One, 9(1), e82356.
Donfrancesco, V. et al. (2019) ‘Unravelling the scientific debate on how to address wolf-dog hybridization in Europe’, Frontiers in Ecology and Evolution, 7, 175.
EU Habitats Directive (1992) Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora. European Union.
Hindrikson, M. et al. (2012) ‘Bucking the trend in wolf-dog hybridization: first evidence from Europe of hybridization between female dogs and male wolves’, PLoS ONE, 7(10), e46465.
Holmala, K. and Kauhala, K. (2006) ‘Ecology of wildlife rabies in Europe’, Mammal Review, 36(1), pp. 17-36.
Iacolina, L. et al. (2010) ‘Y-chromosome microsatellite variation in Italian wolves: a contribution to the study of wolf-dog hybridization patterns’, Mammalian Biology, 75, pp. 341-347.
IUCN/LCIE (2020) 4Genetic Guidelines for the Management of Hybridisation in European Wolves’. Gland, Switzerland: International Union for Conservation of Nature.
Johnson, M. R. et al. (1994) ‘Serologic investigations of canine parvovirus and canine distemper in relation to wolf (Canis lupus) pup mortalities’, Journal of Wildlife Diseases, 30(2), pp. 270-273.
Knobel, D. L. et al. (2014) ‘Dogs, disease, and wildlife’, in Gompper, M.E. (ed.) Free-ranging dogs and wildlife conservation. Oxford: Oxford University Press.
Leonard, J. A. et al. (2014) ‘Impact of hybridization with domestic dogs on the conservation of wild canids’, , in Gompper, M.E. (ed.) Free-ranging dogs and wildlife conservation. Oxford: Oxford University Press.
Lescureux, N. and Linnell, J. D. (2014) ‘Warring brothers: The complex interactions between wolves (Canis lupus) and dogs (Canis familiaris) in a conservation context’, Biological conservation, 171, pp. 232-245.
Lescureux, N. (2018) ‘Beyond wild and domestic: human complex relationships with dogs, wolves, and wolf-dog hybrids’, Hybrid Communities, pp. 65-79.
Linnell, J. et al. (2002) ‘The fear of wolves: A review of wolf attacks on humans’, NINA: Norsk institutt for naturforskning. Available at: https://www.nina.no/archive/nina/pppbasepdf/oppdragsmelding/731.pdf (Accessed: 1 December 2024).
Lojkić, I. et al. (2009) ‘Bites of a rabid wolf in 67-old man in north-eastern part of Croatia’, Rabies Bulletin Europe, 33(3), pp. 5-7.
Mech, L. D. and Goyal, S. M. (1993) ‘Canine parvovirus effect on wolf population change and pup survival’, Journal of Wildlife Diseases, 29(2), pp. 330-333.
Martinello, F. et al. (1997) ‘Detection of canine parvovirus in wolves from Italy’, Journal of wildlife diseases, 33(3), pp. 628-631.
Molnar, B. et al. (2014) ‘Comparative survey of canine parvovirus, canine distemper virus and canine enteric coronavirus infection in free-ranging wolves of central Italy and south-eastern France’, European journal of wildlife research, 60, pp. 613-624.
Moriceau, J. M. (2007) Histoire du méchant loup: 3 000 attaques sur l’homme en France (XVe-XXe siècle). Paris: Fayard.
Müller, A. et al. (2011) ‘Domestic dog origin of canine distemper virus in free-ranging wolves in Portugal as revealed by hemagglutinin gene characterization’, Journal of wildlife diseases, 47(3), pp. 725-729.
Müller, T. et al. (2012) ‘Rabies elimination in Europe: a success story’, In: Rabies control: towards sustainable prevention at the source, Compendium of the OIE Global Conference. on Rabies Control, Incheon-Seoul. 7–9 September 2011. Available at: https://www.openagrar.de/servlets/MCRFileNodeServlet/Document_derivate_00003745/SD2012477B.pdf (Accessed: 4 December 2024)
Pilot, M. et al. (2015) ‘On the origin of mongrels: evolutionary history of free-breeding dogs in Eurasia’, Proceedings of the Royal Society B: Biological Sciences, 282(1820), 20152189.
Randi, E. (2008) ‘Detecting hybridization between wild species and their domesticated relatives’, Molecular ecology, 17(1), pp. 285-293.
Randi, E. (2011) ‘Genetics and conservation of wolves Canis lupus in Europe’, Mammal Review, 41(2), pp. 99-111.
Rupprecht, C. E. et al. (2008) ‘Can rabies be eradicated?’ Developments in biologicals, 131, pp. 95-121.
Salvatori, V. et al. (2020) ‘European agreements for nature conservation need to explicitly address wolf-dog hybridisation’, Biological Conservation, 248, 108525.
Sobrino, R. et al. (2008) ‘Prevalence of antibodies against canine distemper virus and canine parvovirus among foxes and wolves from Spain’, Veterinary Microbiology, 126(1-3), pp. 251-256.
Tietjen, S. et al. (2011) Case report: illegal puppy trade and transport, Germany.
Williams, E. S. and Barker, I. K. (2008) Infectious diseases of wild mammals. Hoboken (NY): John Wiley & Sons.
World Health Organization (2024) Rabies. Available at: https://www.who.int/news-room/fact-sheets/detail/rabies (Accessed: 1 December 2024).