Bison run three times faster than you and hurt more Yellowstone visitors than anything else

A 12-year-old visitor was injured in a bison encounter near Mud Volcano, just north of Fishing Bridge, on the morning of June 26, 2026. Emergency crews transported the visitor to a nearby hospital after the roughly 9:15 a.m. encounter, and the case remains under investigation. In its release announcing the injury, Yellowstone National Park states a fact that has held for nearly half a century: “Bison have injured more people in Yellowstone than any other animal.”

Bison “are unpredictable, can run three times faster than humans and will defend their space when threatened,” the park’s statement continues, a combination of speed and short temper that turns an animal many visitors treat as a slow-moving lawn ornament into the single most dangerous wildlife encounter in the park.

A Mud Volcano Encounter Follows a Pattern Federal Researchers Already Mapped

The June 26 case is not the first close look federal scientists have taken at how these injuries happen, and the park’s own announcement of the incident confirms it remains under active investigation. Cara Cherry, a veterinarian with the CDC’s Epidemic Intelligence Service, led a 2016 review published in the CDC’s Morbidity and Mortality Weekly Report with three National Park Service co-authors, Kirsten Leong, Rick Wallen and Danielle Buttke, examining five bison-related injuries that occurred in Yellowstone during a single stretch of the 2015 season.

Every one of those five injuries, the researchers found, traced back to the same root cause: a failure to keep the required distance from the animal. Two victims were gored and three were tossed into the air; four needed hospitalization, three of them flown out by helicopter ambulance. The victims ranged from a 16-year-old to a 68-year-old, and four of the five were visitors rather than park staff.

Since 1980, No Other Animal in the Park Has Hurt More People

Cherry and her co-authors trace the record back further than any single season: since 1980, bison have injured more pedestrian visitors to Yellowstone than any other animal, they wrote, a distinction that predates the modern era of smartphone photography and viral wildlife videos. Injuries spiked at 33 during 1983 through 1985, prompting outreach campaigns that cut the average to just 0.8 injuries a year between 2010 and 2014, before the 2015 cluster the researchers studied pushed the number back up.

Yellowstone is home to the largest bison population on public land in the country, an estimated 4,900 animals as of July 2015, sharing trails, boardwalks and roadside pullouts with millions of visitors during the park’s peak summer travel months. That scale is part of why the injury count never reaches zero even after decades of signage and outreach: a park with thousands of bison moving freely through developed areas guarantees a steady stream of close encounters, and it only takes one visitor misjudging the distance to produce a case like the one at Mud Volcano.

That pattern makes the June 2026 injury look less like an isolated accident and more like a recurrence of a decades-old problem park managers have never fully solved, despite the signage, education campaigns and printed safety flyers the park distributes at every entrance.

The Park’s 25-Yard Rule Exists Because Bison Outrun Human Reaction Time

Yellowstone requires visitors to stay at least 25 yards, or 75 feet, from bison and other large animals, including elk, bighorn sheep, deer, moose and coyotes, and at least 100 yards from bears, wolves and cougars, according to the park’s current safety guidance. Bison, weighing up to a ton and capable of outrunning a sprinting human by a factor of three, can close a 25-yard gap in the time it takes most visitors to lower a phone and step backward.

The speed advantage explains why the rule is written as an unconditional distance requirement rather than a judgment call based on how calm an animal looks. Cherry’s research team also flagged a seasonal factor: a docile-looking bison can turn aggressive without warning once mating season begins in July, a window that overlaps directly with Yellowstone’s peak tourist season and puts more people near more agitated bulls at the same time.

Close-Range Photography Keeps Driving Visitors Into the Danger Zone

Three of the five people injured in the 2015 cases the CDC reviewed were taking photographs at a distance of roughly three to six feet from the bison when they were hurt, including two who had turned their backs on the animal to frame a shot and one who was taking a selfie. The researchers linked that pattern directly to smartphone adoption, noting that phones with limited zoom range push people physically closer to wildlife than the telephoto lenses many visitors carried in earlier decades.

Two decades earlier, photography played a much smaller role in the injury pattern the same research team tracked. Between 1980 and 1999, only 10 of 35 documented bison encounters, or 29%, involved someone taking a photograph, and most of those photographers stood at least 10 feet away, more than double the 3-to-6-foot distance common in the 2015 cases. Researchers pointed to smart phone ownership, which had reached roughly two-thirds of American adults by 2015, as a likely driver of that shift: a phone’s limited zoom effectively forces a photographer to trade distance for a usable shot in a way a telephoto lens never did.

Park officials have not announced any change to the required-distance rule or the entrance-gate education campaign since the June 26 injury, and the investigation into that specific encounter remains open. What has not changed since 1980 is the underlying math: an animal that can close ground three times faster than the humans watching it leaves almost no room for a visitor to misjudge the gap.

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This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.