Huge bison sheds a single tear in wildlife photographer's beautiful video

 Bison at Yellowstone National Park.
Bison at Yellowstone National Park.

A wildlife photographer has shared a stunning video of a wild bison shedding a single tear on a frosty day and seeming to gulp – a quiet, intimate moment with one of North America's largest land mammals. Philadelphia-based Chris Henry shot the clip in Utah last winter and shared it on his Instagram account recently, prompting a moment of reflection for many of his followers.

"There is always something mythic with these creatures," commented Khalil Hosein.

"The tear with the swallow get me," wrote Mikala O'Brien. "In humans at least, that is classic signaling of stressful/sad nervous system activation… and nervous systems are remarkably similar across biological kingdoms."

It's a powerful video, though as Bryan Amaral, senior curator of the Smithsonian’s National Zoo, explains, humans are the only animals that cry to show emotion.

"Animals do create tears, but only to lubricate their eyes," says Amaral. "Animals do feel emotions, too, but in nature it’s often to their advantage to mask them. Usually, if a zookeeper notices tears in an animal’s eyes, a visit from the vet may be in order to check for an infection or scratched cornea."

The American Optometric Association explains that humidity is generally lower in winter, and which can take a toll on your eyes. A cold wind can cause the moisture on your eyes to evaporate, which then leads to increased production of tears.

If that's something that affects you, Amber Gatti Dunn, OD, suggests using artificial tears before going outside to create a small 'barrier' and protect your eyes,

"I especially recommend preservative-free artificial tears because then they can be used with contact lenses," she says.