A new study published Thursday in Science finds that bringing North America's largest land mammals back to their ancient stomping grounds is breathing new life into grassland ecosystems, with benefits cascading across the food web.
By munching through grasses, bison speed up the nitrogen cycle, supercharging plants with nutrients.
The result: forage that is more than 150% richer in protein—a gift to every creature that feeds on the prairie, from elk and deer to pronghorn and bighorn sheep.