An iconic American animal tromps and chomps its way across the prairie. But this Wild West behemoth doesn’t decimate the grassy landscape. Instead, new research reveals that bison actually stimulate plant growth.
Bison are North America’s largest living land animal. A bison bull may stand nearly seven feet tall and weigh as much as 2,200 pounds! Despite their size, these giants run fast and swim well. They are nomadic (traveling) grazers, moving in large herds across the U.S. and Canadian West.
In November, an article in the Proceedings of the National Academy of Sciences journal revealed another fact: How bison graze improves the quality—and quantity—of their food.
From 2012 to 2017, scientists studied migration in Yellowstone National Park. They found that most hoofed mammals keep moving to find newer, fresher plant growth. Chomp, chomp, chomp. Walk, walk, walk. Scientists call this search for greener pastures “following the green wave.”
God cares about His created beings. That includes birds, lilies, people, and bison. He shows His care by giving each tools for adapting and flourishing. (Matthew 6:26-30)
Researchers noticed that bison in the park migrate differently. Jerod Merkle, a professor in migration ecology and conservation, says that bison “graze in groups of hundreds or more than a thousand.” Other animals groups, such as sheep, deer, and elk, don’t move in such large herds.
When bison graze, they don’t uproot grasses. Instead, hundreds or thousands of sets of chomping teeth shear plants off over large swaths of land. That makes plants shorter, denser, and more nutritious. In fact, the more bison eat, the faster an area greens up.
Intense bison grazing also produces large volumes of dung and urine—natural fertilizers. “[The bison] drop nutrients back on the landscape, which are then available to plants,” Yellowstone scientist Chris Geremia says.
This creates a second green wave, giving bison a steady supply of fresh, healthful grass—and allows bison to graze the same areas over and over.
Researchers used NASA space satellites to detect which areas of the park bison grazed lightly or heavily. Images show that repeated bison grazing “keeps [plants] growing, like a mower clipping a golf course,” says Geremia. He and Merkle were both part of the migration study team.
“Bison don’t just move to find food, kind of the classic way that we think of animal migration,” Geremia observes. “They create good food by how they move and how they graze.”