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Is it true that "hybrids" are more dangerous than "pure" wolves?

da

Wednesday 18 December 2019

da

Wednesday 18 December 2019

To answer this question it is first necessary to make some clarifications and explain the meaning of the hybrid term referring to the animal world, because there is a lot of confusion and exploitation in this regard.

Hybrid it is that individual generated by the union of two animals belonging to different species or subspecies that has genetic and often also morphological characteristics intermediate to the parent species.
A first generation hybrid individual is also referred to as F1.
Here is an example of two first generation hybrid animals: the hinny, generated by the mating between a male horse and a female donkey, and the Mule, hybrid born from the cross between male donkey and female horse.

09.Moriles Mula.JPG
Hybrid F1 Mule
Di Juan R. Lascorz - Own work, CC BY-SA 4.0, connection

Old hinny in Oklahoma.jpg
Hybrid F1 Bardotto
Di Don't be angry - Own work, CC BY-SA 4.0, connection

When the union occurs between two individuals of different species (Interspecific) like the horse and the donkey, it usually generates sterile offspring and the hybridization process immediately stops at the F1 hybrid which cannot transfer characteristics to other individuals because it is unable to reproduce.
When the union occurs between individuals belonging to the same species but different subspecies (Intraspecific) Generally the first generation F1 hybrids are fertile and can in turn reproduce with one or both parent species of origin, becoming the means for the passage of genes: this phenomenon is defined introgression e individuals are defined introgress hybrids or simply introgressed.
The introgression has a powerful evolutionary force because it can introduce new characteristics to the species of origin.
When it occurs in the absence of anthropogenic conditioning, or rather caused by man, it is a completely natural process that has always existed and that has most likely played a fundamental role in the evolution of many species.
Hybridization is anthropogenic, that is, caused by man, when the cross occurs between domestic and wild species, such as for example between pig (Sus scrofa domesticus L.) and wild boar (Sus scrofa scrofa) and when it consequently intervenes in modifying the natural reproductive isolation between species or subspecies. 
Introductions, especially for hunting purposes, animal escapes from farms, more or less accidental releases, are typical situations that introduce into the environment some species or subspecies not present originally, therefore possibly the cause of numerous problems, including that of hybridization with native species or rather evolved in those places and present in the wild.
Several wild subspecies belong to the wolf species: in Eurasia there are three of them: the canis lupus lupus (grey Wolf) present in most of Europe, Norway and Asia, Il The dog Wolf (Apennine wolf) present in Italy and expanding in Europe and the Canis lupus signatus (Iberian wolf) present in northern Portugal and northwest of Spain.

CANIS LUPUS ITALICUS - Photo by Stefano Manfredini

CANIS LUPUS LUPUS  - Photo by Stefano Manfredini

CANIS LUPUS SIGNATUS - Photo by Stefano Manfredini

Thanks to the dispersion capacity of the wolf, capable of moving even thousands of kilometers, we are witnessing a phenomenon of natural hybridization between wolves of different subspecies: the The dog Wolf and Canis lupus lupus.
In the Eastern Alps individuals of canis lupus lupus, coming from Eastern Europe, they joined individuals from The dog Wolf, giving rise to new herds and to F1 hybrid individuals who re-crossing with wolves of one or the other subspecies will contribute to the spread of new genes in the population.
The natural encounter between these two wild subspecies is an important evolutionary path that will allow to improve the genetic variability of the population, with many positive consequences that go beyond the present article.
We want to make yet another consideration, in our important opinion, on the communicative meaning and unscientific of the term hybrid which is very often used and perceived with a negative meaning, leading people to think of the hybrid as something monstrous and completely unnatural, when on the contrary it is a process already present and frequent in biological dynamics.

We now come to face the wolf x dog hybridization, the union between domestic animal and wild animal, a phenomenon determined and conditioned by man.

The dog (Canis lupus familiaris) which belongs to the same species as the wild wolf, is a subspecies domestic obtained through the process of domestication of the wolf by man which took place between 15.000 and 30.000 years ago.
The union between wolf and dog generates fertile first generation F1 hybrids.
All breeds of dogs, from Great Dane to Chiwawa, have wolves as ancestors.
It was the man who, through innumerable crossings and re-crossings, gave birth to the dog, to make it suitable for his needs by selecting many breeds different from each other in size, colors, but also for attitudes and characteristics.

The wolf, on the other hand, is the result of millions of years of evolution, during which natural selection has made it exactly what it is, fixing in its genetic heritage the best adaptive characteristics to life in nature. The great concern of the entire scientific community regarding the phenomenon of wolf x dog hybridization (wild with domestic) is that of compromising the genetic integrity of the wolf, with the risk of transferring to the wild animal characteristics of the domestic animal that are not very adaptive to the species. wild, with consequences that could be disadvantageous for the wolf: greater vulnerability to diseases to which it is resistant, greater fertility (the wolf has one estrus per year and the dog two) and, potentially, also less efficiency as a predator, assuming more conflicts with human activities. Well-founded hypotheses, even if currently without evidence.
Currently in Italy the data on the presence of hybrid individuals are fragmented and uneven: on the Alpine arc, only one hybrid individual was found in Piedmont, while in the Tuscan province of Grosseto 52% of the lupine population is made up of hybrid or introgress individuals.  

 

It is important to understand the causes of dog x wolf hybridization.

In our country, hybridization peaked in the 90s of the last century, a period of great expansion of the wolf, and most likely occurred due to the high number of wandering *, stray * or feral * dogs present throughout the territory. , in conjunction with the low density of wolves. Some female wolves, instead of encountering male wolves, encountered dogs (wandering, stray or feral) with which they reproduced, giving rise to first generation F1 hybrids born and raised in the wild. The natural dispersion of individuals then contributed to the spread of hybrid specimens far from their territories of origin and the subsequent multiple unions between F1 hybrids and wolves gave rise to introgress hybrids.

  • Stray dog: animal with owner but not guarded and free to roam
  • Stray dog: animal without owner who lives autonomously but accustomed and fed mainly by man
  • Feral dog: animal that lives in nature in the wild, feeds on its own and has no contact with humans.

Currently wolves are widespread in almost the whole country and the chances of two individuals of opposite sex not meeting are remote; however, other reasons may arise to cause new cases of hybridization. The first is always the same, ie the presence of stray, stray or feral dogs; the second is linked to the deconstruction of the flocks generated by anthropogenic causes: poaching and road accidents. For example, if in a pack of wolves the dominant male is killed in the female's estrus period, this could be covered by a dog, raise newborns in nature and give rise to the problem that will drag on for many other generations; or, in case of death of the dominant pair, other females of the herd could go in estrus and reproduce with dogs.
We want to underline how even canine vagantism affects the dog x wolf hybridization. Stray dogs are those animals that have an owner and a house but are not kept. And there are really a lot of these dogs. There are many owners who leave their dogs full freedom, who can thus leave their home independently at any time of day or night, profoundly interfering with natural dynamics, disturbing the fauna, meeting wolves and also putting their own at risk. safety.

 

When is a wolf considered hybrid?

Traditional genetic analyzes are currently able to detect the degree of introgression up to a maximum of 5 generations. This means that if a wolf and a dog have mated and their children, grandchildren and great-grandchildren have subsequently mated only with other wolves, the genetic traces of the dog will be detectable only up to five generations later; subsequently the dilution of the canine genes will be so high within the lupine genes that only the latter emerge, and therefore the genetics will turn out to be a pure wolf.

Put simply: an F1 hybrid will have, on average, 50% dog DNA and 50% wolf DNA. If the F1 hybrid mates with a wolf, their offspring (also called "first backcross 1", or "BC1") will have about 75% wolf DNA and 25% wolf DNA. dog. If an individual of BC1 offspring mates with a wolf, it will give birth to individuals (BC2) with 87.5% wolf DNA, then (BC3) about 94% wolf DNA, then (BC4) about 97%, wolf DNA. wolf finally (BC5) almost 99% of wolf DNA.

Considering the natural genetic variability of pure wolves (no one is the same as the other), it makes hybrids introgressed beyond 5 generations virtually indistinguishable from pure wolves, except for the use of expensive and complex genomic analyzes. 

 

How are dog x wolf hybrids different from pure wolves?

Hybrid wolves can sometimes have anomalies in appearance (phenotypic anomalies) inherited from the dog, sometimes instead they have an identical appearance to wolves that are pure in genetics (called wild type, or "wild phenotype"). 

On: The dog Wolf - lupo pure (wild type) Photo by Stefano Manfredini

On: Hybrid - With anomalous phenotypic characteristics - Photo Oasi Lipu Castel Guido
On: Hybrid with wild phenotypic characteristics (wild type) Photo Oasi Lipu Castel Guido

And when are wolves black?

Melanism (black coat) is caused by a single mutation in a single gene locus that appears to have been inherited from the dog. This mutation may have been established in Italian wolves centuries ago (as for the wolves of Alaska, Canada and the western United States), but also more recently, so only a genetic examination can give a certain response and indicate whether a black wolf is still to be consider itself hybrid or now completely pure.

In truth, an answer on which animals should be considered hybrids should be given by the legislator. Do we consider hybrids only those wolves that are not pure in genetic analysis? Or do we also consider those wolves with phenotypic anomalies as hybrids, regardless of the genetic result? And in this second case, what are the anomalies to consider?
There is an appendix attached to the Wolf Management and Conservation Plan in Italy, still NOT approved, which defines how to identify hybrid animals with respect to their phenotype (appearance). In particular, some characters (for example the white nails or the fifth toe - the so-called spur - on the hind legs, have only been observed in dogs or hybrids, but never in pure wolves. Unfortunately without an approved plan, this important document is not applicable.  

 

But let's get to the initial question: is it true that hybrids are more dangerous than pure wolves?

The perception of the term hybrid, the exploitation, the bad information on the subject leads to believe and / or to make many people say that dog x wolf hybrids are more dangerous, they are less afraid of people, they get closer to homes than pure wolves, just because they are hybrids.

We are talking about animals born and raised in nature for which studies, research and observations to date do NOT show any behavioral difference compared to pure wolves.
The wolf is a cultural animal: the behavioral characteristics of puppies are learned and acquired thanks to the teachings and examples given by adults.
Even the distrust and fear of humans, as well as hunting strategies, the preference of prey species, the recognition of possible dangers, safe paths and places in which to move and rest are aspects largely learned through cultural transmission. . The possible presence of wolves close to the villages, if dictated by natural reasons (eg presence of prey species) is not in itself an atypical behavior.
It is instead the habituation to man that can decrease in wolves, pure or hybrid that they are, the natural diffidence towards man: behavior consequent to some human practices (for example the incorrect management of slaughterhouse waste or breeding) which have the effect of attracting animals in anthropized contexts with food resources.
The phenomenon of wolf x dog hybridization is to be kept under careful observation because of the evolutionary scope that it could have at the expense of the wolf; for this reason also our association considers it necessary to stem the phenomenon by acting mainly and urgently on three fronts:

 

  • Act on the management of dogs, the origin of the problem.
    If the dogs are handled correctly, the encounters with the wolf will be greatly reduced;
  • Take action on hybrid wolves: capturing, sterilizing and releasing hybrid individuals in nature is a non-bloody intervention that does not impact on the structures of existing herds and which favors the phenomenon of dilution of canine genes;
  • Stop poaching: very high on the species, which, causing the disintegration of families, indirectly favors the phenomenon.

But in order to act concretely, a clear political decision based on scientific data is needed, which responsibly approves finally the Wolf Management and Conservation Plan in Italy, prepared by the best scientists and technicians, which proposes targeted and punctual interventions and actions also for management of hybrids. Unfortunately, the Plan continues to remain closed in some drawer and is cyclically exploited by the same policy, immobile in its non-decisions, at the expense of dogs, men and wolves.

 

Insights 

Specific projects on hybridization
http://www.lifemircolupo.it/
http://www.ibriwolf.it/ 

melanism
http://italianwildwolf.com/2011/03/25/neri-come-la-notte/

Studies on wolf x dog hybridization:
https://academic.oup.com/mbe/article/34/9/2324/3855352
http://italianwildwolf.com/2017/07/28/siamo-sicuri-che-sono-proprio-ibridi/ 

Wolf management and conservation plan March 2019:
https://www.iononhopauradellupo.it/il-testo-integrale-de-il-piano-di-conservazione-e-gestione-lupo-in-italia-marzo-2019-depositato-in-conferenza-stato-regioni/

Cover photo by Stefano Manfredini
A special thanks to the Scientific Committee I'm not afraid of the wolf.