In the winter of 2011, a remote Russian town was besieged by a pack of more than 400 wolves.

Verkhoyansk is located in one of the coldest and most remote regions in the world. (It also sits within “Stalin’s Death Ring,” where the Russian dictator once exiled his enemies.) These days, the weather during the winter months is no less harsh. It’s so cold that houses literally snap in two under the weight of ice on their roofs. Nevertheless, about 1,300 people call Verkhoyansk home.

In February 2011, it got worse, when 400 wolves began attacking homesteads. Within four days, the hoard had killed 40 horses and paralyzed the residents of Verkhoyansk with fear. A state of emergency was quickly declared and a bounty of $300 was put on each wolf’s head. More than two dozen teams of hunters came to the town, patrolling the streets on snowmobiles while throwing down as many traps as they could find. Helicopters were supplied by government officials shortly thereafter and the hunters began picking off the wolves from the air.

Fortunately, no human casualties were reported. After it was all over, wildlife experts admitted that they weren’t entirely surprised by the super pack. They theorized that it must have formed from the desperate survivors of over 100 smaller wolf packs. The winter of 2011 was harsh in the region, even by Siberian standards, meaning that their usual prey was likely killed off by the extreme weather conditions. With nowhere else to turn for food, the wolves banded together and began tearing into Verkhoyansk’s livestock. Further contributing to the problem: a population boom. In 2011, an estimated 3,500 of the animals were believed to be living in the region. According to experts, the area could sustain only about 500.