Nearly Half of Italy’s Wolves Are Part Dog Now, Thanks to Hybridization. Is That a Threat to the Species?

Between 15,000 and 30,000 years ago, a now-extinct population of wolves evolved into dogs, with a little help from humans. Today, at least in Italy, home to one of Europe’s largest wolf populations, the genes flow in the opposite direction. Recent genetic testing suggests that, particularly in the central and southern regions of the country, almost half of wild wolves (Canine lupus) are actually wolf-dog hybrids.

This represents a sea change from the 1970s, when Luigi Boitani, now president of the International Union for Conservation of Nature’s Large Carnivore Initiative in Europe, discovered the country’s first known wolf-dog hybrid.

The 1970s were a period of transition for Italian Wolves. At the time, the population was coming out of a downward spiral. New laws and conservation efforts were designed to encourage wolves to recolonize habitat from which they had disappeared. But the landscape and its inhabitants have changed. The wild countryside had given way to rampant urbanization, and areas of central and southern Italy, where wolves began to recover, were home to large numbers of free-roaming dogs. It didn’t take long for wolves to start rubbing shoulders (and more so) with local canines.

Decades later, Rita Lorenzini, a biologist and director of Italy’s Experimental Zooprophylactic Institute of Lazio and Tuscany, worked with her team to analyze hundreds of DNA samples collected from a region stretching from Bologna to the tip of Italy’s boot. Their analysis, published in January in the journal Biological conservationreveals how close the two canid species have become.

Lorenzini’s research focused on genetic material collected from 748 wolves found dead between 2020 and 2024, and another 26 collected between 1993 and 2003. The team found that 47% were wolf-dog hybrids. And while some of these animals are descendants of hybridizations that took place generations ago, others are more recent crosses, showing that hybridization is still occurring.

Hybrids are not easy to spot. While some people suggest that wolf-dog hybrids have distinctive physical characteristics, such as darker fur than non-hybrid wolves, Paolo Ciucci, a biologist at the Sapienza University of Rome who worked with Lorenzini on the recent study, says that scientific evidence for these visual differences is lacking and that genetic analysis remains the most reliable way to identify a hybrid.

But the extremely high presence of wolf-dog hybrids in central and southern Italy, Ciucci says, poses a threat to the future of the country’s wolves.

A wolf living in a healthy, stable pack in the wild is unlikely to breed with a free-ranging dog, Ciucci says. These wolves are more likely to view a dog as competition, or even prey. But when the pack structure breaks down and the female wolves find themselves alone in an area full of free-roaming dogs, the dynamic can change.

While Italy is home to nearly 3,300 of Europe’s approximately 21,500 wolves, the fact that so many of them are actually dog ​​hybrids poses a silent danger, Ciucci says. Italian wolves may be near a point of no return that experts call ‘genetic flooding’“, in which the original wolf gene pool is irreversibly replaced by that of hybrids. In simple terms, this means that the wolf, genetically speaking, could become extinct.

In northern Italy, where there are fewer free-ranging dogs, wolfdog hybrids are much rarer than in the central and southern regions of the country. But that, Lorenzini says, is probably temporary. Wolves can travel vast distances, and hybrids could eventually mix with wolves in northern Italy, or even throughout Europe.

Of course, wolves and domestic dogs have been breeding – and therefore hybridizing – since they first diverged thousands of years ago. In North America, for example, gray wolves with black coloration are thought to be distant descendants of wolf-dog mixes. Research suggests that these dogs even gained some benefits from their interspecies mixing. Black wolves are in fact more resistant than their peers to certain diseases, such as distemper, and they can also be more successful in hunting in the forest.

But what’s happening in Italy is totally different, Lorenzini says, because of the scale and speed at which it’s happening.

Astrid Vik Stronen, a geneticist at the University of Ljubljana in Slovenia who was not involved in the research, agrees that the possible downsides of hybridization outweigh the potential benefits. “Overall,” she said, “I think the main concern is that it would be a risk. »

The abundance of wolf-dog hybrids in Italy, Ciucci adds, threatens to disrupt the key role wolves play in the ecosystem. Although researchers know little about how hybridization affects how wolves function because it’s difficult to study the animals in the wild, Ciucci says it’s possible that hybridization could lead to changes in their physiology and behavior, such as how they hunt, how they find and defend their territory, and how they interact socially.

For Ciucci, widespread hybridization also jeopardizes the uniqueness of the species. “The authenticity of the wolf species [is going] missing, with all its cultural, ecological and evolutionary value.

It’s something that Boitani has worried about – and warned against – ever since he discovered that first hybrid decades ago. “Perhaps because I am a little old-fashioned,” says Boitani, “and because I am attached to the idea of ​​the wolf as I have always known, dreamed and lived it… [but] I oppose the idea that tomorrow all Italian wolves will be naturally hybrids.

This story was originally published in biographicalan independent nature and reclamation magazine powered by the California Academy of Sciences.