[PL] Brutal selection on the front lines. Study: War rapidly changing Ukraine's dog population

Translated using deepl.com.

Researchers—thanks to data collected by Ukrainian soldiers on the front lines and volunteers in other parts of Ukraine—have examined how the population of wild dogs in frontline areas has changed. The scale of the changes is enormous. Mainly small, healthy dogs with “wild” characteristics survive.

“Our study clearly shows that war affects not only humans but also other species, primarily by accelerating and directing natural selection,” commented Prof. Marija Marciw from Ivan Franko National University of Lviv, the lead author of the study described in the journal Evolutionary Applications, to PAP.

In areas affected by warfare, animals face not only explosions during shelling, bomb and mine blasts, noise, and constant stress. They also face the challenge of rapid changes in the population of such areas: there are fewer people feeding the animals, there is a lack of food scraps, agriculture is disappearing, and with it, additional sources of food.

“In terms of its impact on animal populations, war is a man-made disaster that has very long-term effects on the entire natural world,” said Dr. Małgorzata Pilot from the University of Gdańsk in an interview with PAP.

The research was conducted between March 2023 and January 2024. The data was obtained thanks to the involvement of volunteers – soldiers stationed on the front line. The initiative was launched by Dr. Ihor Dykyj from the University of Lviv, who, after the outbreak of the war, spent over a year on the front line as a soldier and organized a data collection campaign among soldiers there.

In regions far from the front line, information about wild dogs was also collected by civilians, including people working in shelters. If the dogs approached people, volunteers recorded their size, weight, and health, photographed them, and collected hair samples. The project collected information on more than 760 dogs. Obtaining data from dogs did not require specialist knowledge or equipment, making it possible to conduct research using the opportunities offered by citizen science and without exposing people or animals to additional danger.

“We wanted to see if dogs on the front lines differed from those in safer parts of the country. The results are striking—we observed a drastic decline in morphological diversity,” explains Dr. Pilot.

Most of the dogs registered are medium and small in size. Scientists believe this is related to the dense mining of the area – smaller animals are less likely to activate mine detonators, which are designed for humans or vehicles.

• We did not encounter any dogs with flat snouts on the front lines, which is probably due to their lower respiratory capacity. There were also no dogs with short legs, which are unable to move efficiently in difficult terrain. Most of the dogs on the front had straight, medium-length coats. The characteristics typical of decorative breeds disappeared, and the population became more like wild canines, concluded Dr. Pilot. Prof. Marciw added that dogs of the so-called wild type, which are genetically better adapted to harsh environments, cope best in extreme conditions. The researcher also noted that the average life expectancy of animals on the front lines has shortened – old or sick individuals are almost non-existent there.

Dr. Małgorzata Pilot pointed out that the duration of the war – compared to the scale of evolution – is short, but it forces a “brutal form of selection.” “This is not a gradual process where better-adapted individuals simply have slightly more offspring. Here, weaker individuals die immediately. This is evidenced by the fact that we encountered almost exclusively healthy animals on the front line, except that many of them show signs of malnutrition,” she commented.

The team managed to examine mainly those dogs that rely on human help. However, recordings from military drones prove the existence of groups of completely independent dogs, living in packs and hunting or feeding on carrion.

• Reports of dogs eating the bodies of fallen soldiers whose corpses are not removed from the battlefield have been confirmed. Although it sounds drastic, dogs, like wolves, are physiologically adapted to feeding on dead animals and can also feed on dead humans when no other food is available, Dr. Pilot pointed out. Research has not yet determined whether dogs eating human remains is extreme behavior or rather typical in such difficult conditions.

The researchers also analyzed the diet of dogs approaching humans by studying stable isotopes in their fur. It turned out that animals throughout Ukraine currently consume a lot of plant-based food. "This is a result of the crisis. People are throwing away less meat and feeding it to dogs less often, replacing it with other products: groats, bread, or potatoes," says Dr. Pilot.

Until now, the impact of wars on ecosystems has usually been studied post factum or in laboratory conditions. This time, science is documenting the changes live. Prof. Marciw emphasizes that dogs, as a species accompanying humans, are a good indicator of the scale of environmental degradation. “The data collected will help to document the drastic environmental changes caused by the war and, in the future, to restore the unique natural habitats that have been destroyed by the Russian occupiers,” concluded Prof. Marciw.

Ludwika Tomala (PAP)