This deer in Montana is chowing down on a bloody meal: flesh from its own antlers! The scene may look gruesome, but it’s a normal and painless part of a male deer’s life.

Male deer, or bucks, use their antlers to impress females and to fight with males over potential mates. Deer lose their antlers each winter and grow a new set each spring. Soft, fuzzy velvet covers a deer’s developing antlers. This tissue is chock-full of nutrients that help with antler growth.

As fall approaches and bucks get ready to spar, their velvet starts to fall off. That exposes the hard, bony antlers underneath. Deer often scrape their antlers against trees and bushes to get rid of the velvet. Then the animals use their teeth to pull off any strips of tissue dangling from their antlers.

“This deer just kept chewing on the velvet and swinging his head, trying to get it back in his mouth,” says wildlife photographer Donald Jones, who captured the image shown. Because velvet contains loads of blood vessels, shedding the tissue can be a gory process. But, says Jones, “it’s a natural and important one.”

As deer remove their antlers’ velvet, they often eat the pieces. “When the tissue is still fresh and moist, it’s full of minerals and vitamins,” says Kurt VerCauteren, a biologist at the National Wildlife Research Center in Colorado. Deer just can’t resist the nutritious snack, he adds.