Onlookers watch as large bison dies in scalding Yellowstone hot spring

USA Today

3 days ago

Onlookers at one of Yellowstone National Park's most popular sites watched a large bison take its final steps into a scalding hot spring and die in a horrifying reminder of what can happen away from the safety of marked paths.
The bison wandered into the Grand Prismatic Spring, located in the part of the park within Wyoming's borders, the morning of June 21, officials said. Photos and video posted by onlookers to social media show the bison appear to thrash around before slipping into the spring's waters, behind a curtain of steam.
Katie Hirtzel, an Amazon driver from the Salt Lake City, Utah, area, saw the bison's remains resting in the spring hours later.
"It's quiet, it's eerie, I couldn't really tell what it was at first," Hirtzel told USA TODAY. "I honestly found the whole experience so beautiful and inspiring to be able to see that raw power right in front of my face."
Hirtzel, her husband and their 13-year-old son were visiting the park and spent four days camping in the area. She said when they went back to the Grand Prismatic Spring the next morning, the bison's remains were still there and didn't look at all changed. She hopes park rangers will leave the bison in its final resting place, as part of the "circle of life."
Over time, the scalding hot water of the springs will take its toll on the bison's remains, said Mike Poland, the scientist-in-charge of the Yellowstone Volcano Observatory with the U.S. Geological Survey. Poland said it's likely that the National Park Service rangers will leave the bison to decay naturally, but will keep an eye out just in case scavenging animals get too close to the busy tourist attraction and pose a risk to visitors.
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It's not unheard of for animals to fall victim to Yellowstone's dangerous natural landscape, Poland said, but it is rare for so many to witness it at a popular sightseeing spot. It's also an important reminder to visitors, he said: Stay safely on the boardwalks and marked trails to avoid serious injury or death.
How hot does the Grand Prismatic Spring get?
The Grand Prismatic Spring is Yellowstone's largest hot spring and one of the largest in the world, at between 200 and 300 feet in diameter and more than 121 feet deep.
Its waters are really, really hot. Poland said the spring is shallow around its edges, where its water appears bright red in color due to bacteria and water is relatively cooler. Toward the center, the water gets deeper and hotter and colors change from red to a deep blue, he said.
At the surface, temperatures have been recorded at about 192 degrees Fahrenheit, which is just under the boiling temperature of 200 degrees at that altitude, Poland said. Deeper down, water likely reaches boiling temperatures, he said. The temperatures in the spring are not survivable for long, he said. People who have strayed from designated paths around Yellowstone's thermal features have suffered second- and third-degree burns, or even died.
Though it's morbid to think about, the bison's remains are essentially being "poached," Poland said. Over time, the boiling water will break down the flesh and tissue of the bison and only its skeleton will remain, he said. It's a common misconception that Yellowstone's springs will eat away at flesh because they are acidic; in fact, Poland said the majority of the springs in the park are neutral, not acidic.
See photos of the bison at Grand Prismatic Spring
Do animals at Yellowstone have special instincts to avoid hot springs?
Hirtzel said she was shocked to see the animal dead in the hot spring, and she and her family and just been discussing how the animals that live in Yellowstone must know to avoid the springs.
Wildlife at the park don't have any special instincts to stay away from the hot springs, Poland said. Like humans, they can sense increased temperatures as they walk near the springs and can probably tell there is danger. Still, there is plenty of evidence that animals dying in hot springs is not terribly uncommon, Poland said.
In fact, there is a spot a few miles away from the Grand Prismatic Spring in the Lower Geyser basin known unofficially as "Skeleton Pool" because of how many animal skeletons have been spotted there. Animals can even be drawn toward the park's hot springs during freezing winters as a source of warmth, sometimes ending in a deadly misstep.
"We know animals aren't immune to making mistakes," Poland said. "This probably happens more often than we would know because a lot of times this won't be observed... that this happened at Grand Prismatic right during the summer when people are watching is a unique event."
The bison that died appeared to get itself into a tough spot while walking around the hot spring's crust and started to get burned by the water, then thrashed around and got itself into deeper, deadlier water and couldn't recover, Poland said.
That's why it's so important for people not to leave the boardwalks around the hot springs, he said. Even if it looks like you are stepping on solid ground, the ground can be thin enough to give way to scalding waters when you step on them.
"This is why the boardwalks and trails are where they are," Poland said. "It prevents damage to the thermal areas and it also prevents people from getting into bad situations."