The 100-Yard Rule (and the Selfies That Break It)
Why park biologists keep begging visitors to back up — and what actually happens when they don't.
Park rules are blunt for a reason: 100 yards from bears and wolves, 25 yards from everything else. That's the length of a football field for predators, and a tennis-court diagonal for bison, elk, and moose. The rule isn't about etiquette. It's about the distance at which a 2,000-pound animal can no longer reach you before you can react.
Bison gore more people in Yellowstone every year than bears do. They look slow. They are not — a sprinting bison clocks 35 mph, faster than any human who has ever lived. The classic injury pattern is a tourist who approached for a photo, turned to walk away, and was hooked from behind.
The good news: 400mm is cheap. A used 100-400 zoom on any modern mirrorless body will get you National Geographic-grade frames from a respectful distance. The animal stays calm, your photos get better, and nobody ends up on the evening news.
If an animal changes its behavior because of you — head up, ears back, stopped eating — you are too close. Back up slowly. Don't run. Don't turn your back on a predator. And put the phone down.