A team of scientists discovered a wolf that swam 1.5 kilometers through icy waters to avoid roads and villages.
The wolf, called M637arrived at the lake shore through a shortcut.
In Switzerland in February the water temperature is only about 5°Ccold enough to kill a human being in a few minutes.
Instead of following the shore around villages and roads, the wolf went straight into the water and swam across.
During about 90 minutesmale wolf M637’s GPS collar recorded a route across the lake. One location even placed it in the middle of the water. When he emerged on the other side, he had crossed about 1.5 kilometers of an icy alpine lake.
“At first, I looked for scenarios in which the animal had actually gone around the lake. A complete return to the lake would not have been possible in that period of time,” said the biologist Flurin Kunz.
According to , at the end of October 2025researchers from KORA, the Swiss foundation that monitors carnivores, captured him and fitted him with a GPS collar.
M637 was a young adult male, with three to four years old. Young adults often leave the pack where they were born and begin long journeys in search of free territory.
This movement, called dispersalis one of the main ways wolves spread into new regions and keep distant populations genetically linked.
At first, the M637 explored the Canton of Juraclose to the French-Swiss border. He spent some time in the French mountains, then returned to Swiss territory. In January, his movements became much bolder.
The wolf covered almost 240 kilometers in just 11 dias.
During its movement, the wolf crossed farms, towns, roads and highways. The animal later arrived at Lake of the Four Cantonsan extensive body of water surrounded by mountains. Faced with the obstacle, instead of going around it, M637 chose to swim across it.
Although wolves are not specialized aquatic animals, they can swim effectively. To the paws help with propulsiona coat offers some thermal insulation e buoyancyand so on physical resistance of the species allows you to tackle difficult routes.
According to the researchers, there is already evidence that these animals can move through water in different contexts. On the coast of British Columbia, Canadathere are wolves that regularly move between islands, explore coastal areas and even fish. They are sometimes called “sea wolves” and can travel long distances in cold waters.
The Swiss case is, however, relevant because it occurred in a densely populated region, with locations close to the lake, agricultural areas and tourism. The movement of M637 demonstrates that wolves can find routes even in very humanized landscapes.
Researchers assume that a lake, a highway or the edge of a densely populated area will reliably contain a wolf, M637’s trip demonstrates otherwise. Wolves use bridges, underpasses, forests, the dark of night, and sometimes water.
After the crossing, M637 continued into the alpine interior, crossing mountains and villages. Between the end of January and the beginning of March, it covered around 739 kilometers on an uncertain path, typical of a young male in dispersion.
Finally, until it finds territory and a partner, its trajectory continues to offer clues about the resilience and mobility of the species.
