A pack of wolves attempted to take down a bison calf earlier this spring — but the calf’s mother had different ideas. In an impressive display of “antipredator behavior,” the powerful female bison fought off four determined wolves while the circling canines snapped at her flanks and repeatedly lunged at the small calf that was glued to her side. After a lengthy effort, the mother walked away with her calf in tow, and the defeated wolves retreated into the sagebrush. Watch the wild scene unfold for yourself below.

Wildlife viewing guide Michael Sypniewski filmed the interaction while shuttling clients through the park in search of wolves. His series of short videos shows the bison shaking its horns violently and charging the wolves one by one. They work in tandem to draw the newborn away from its mother, but she thwarts the pack’s advances at every turn.

“Raising a kid in wolf country is no easy task,” wrote Sypniewski in the video’s caption. “For twenty minutes, these two icons of the West battled back and forth. The wolves snapping jaws, often getting within inches of the newborn.”

While countless videos of bison and wolves emerge from Yellowstone every year, Sypniewski’s footage is notable because it’s not all that common for wolves to prey on or attempt to prey on bison in the park. In a paper published in the Journal of Mammology in November 2000, researchers detected only 14 wolf-killed bison throughout the course of a three-year study.

Most of the recorded kills included cows or calves and occurred in late winter or early spring, when bison are weakened from the ravages of winter and their calves are still small and vulnerable. The study found that Yellowstone wolves prefer to prey on elk over bison because they’re more abundant and easier to take down.

“This was a masterclass on defending against predators,” Sypniewski noted. “Keeping her calf tucked close to her side, the mother—always aware of each wolf—was constantly using her body to shield the calf. The two eventually outlasted the persistent predators and the wolves were forced to watch as they safely returned to a distant herd.”

Related: Watch a Pack of Wolves Kill a Bull Elk in Brutally Slow Fashion

A fully-grown female bison can weigh up to 1,000 pounds and reach a height of four or five feet, according to the U.S. Department of the Interior, while bulls can exceed 2,000 pounds and often stand 6 feet tall at the shoulder. Wolves typically weigh between 60 and 145 pounds.

The National Park Service says that the bison population in Yellowstone fluctuates between 3,500 and 5,000 animals. There are seven distinct wolf packs in the park: the 8 Mile pack, the Junction Butte pack, the Wapiti Lake pack, the Rescue Creek pack, the Mollies, the Cougar Creek pack, and the Belcher pack. Like bison, wolf numbers tend to fluctuate, but survey counts haven’t exceeded 180 individuals since the canines were reintroduced on the park’s northern end 28 years ago.