Here’s a reindeer story you may not want to tell the kids: Golden eagles have been spotted attacking full-grown reindeer in Norway.

The golden eagle (Aquila chrysaetos) is a pretty tough bird. With a wingspan up to 7.5 feet and a diving speed of more than 150 miles per hour, A. chrysaetos is generally pretty good at getting what it wants. That usually means rabbits, hares, birds, and squirrels. But when the pickings are slim, golden eagles will get a little more ambitious, going after sheep, saiga antelope, and even wolves. Researchers even saw one brazen bird carrying off a bear cub.

So the idea that these birds are preying on reindeer is not quite as ridiculous as it sounds. It was a fact well known by the reindeer-herding Sami people of Finland, who had complained of the attacks for years. But scientists, being scientists, were still having a hard time believing it in the absence of evidence.

Then in 2009, researcher Harri Norberg of the Finnish Wildlife Agency took a closer look at the carcasses of reindeer calves. The forensic evidence showed that the majority of them had indeed fallen prey to golden eagles. Not too long after, a BBC film crew captured a handful of attacks on camera. The reality was not pretty.

An attacking eagle drops out of the sky above its prey, and then drives its talons into the reindeer’s body, puncturing large blood vessels.

"They are not killing anything instantly, so they have to ride like a rodeo cowboy on the back of the calf," film producer Ted Oakes told the BBC. After that, it’s just a matter of waiting for the reindeer to bleed out.

Norberg and Oakes suspected that the reindeer calves were not the eagles’ only victims, but, once again, they had no proof. 

Six years later, a Norwegian naturalist has seen it for himself. Olav Strand of the Norwegian Institute for Nature Research told New Scientist that he has seen golden eagles kill adult reindeer weighing more than 130 pounds.

Strand believes the attacks are an indirect consequence of human activity. Harsher winters—a result of climate change—are making small prey like hares harder to come by. At the same time, human settlements are shrinking available reindeer territory, driving the animals into a smaller area, where they can be more easily picked off. "It’s possible to expect some kind of interaction between the level of fragmentation and the coming climate change," he told New Scientist. "Through history, the only defense reindeers have had to climate and predators has been to move."