Grizzly Bears and Bison Carcasses Yellowstone National Park 2014

During May 2014, two winter-killed partially submerged adult bison carcasses attracted up to ten different grizzly bears on the Yellowstone River in Yellowstone National Park, Wyoming. Several massive boars were in control of the carcasses but many younger and smaller bears shared this windfall of nutrition. The bears took turns eating and rarely visited the carcasses together. Once the largest males were done feeding, the less dominant bears would seize the opportunity and wander down to the river. I observed the bears tearing at the carcasses as they eagerly consumed the bison; these bears were able to lift the massive soaking carcasses out of the water and several of the bears stood feeding in the frigid water for hours at a time. When bears emerge from hibernation, they seek out readily available nutrient dense food sources such as winter-killed ungulates. In Yellowstone National Park, elk, bison, and deer carcasses remain frozen and preserved offering life saving sustenance. These are the fast easy frozen dinners that these massive land carnivores crave following hibernation.

Grizzled
One of the largest, oldest, and dominant bears takes his turn at the carcasses. This boar was unchallenged and when he approached the river, all of the other bears would abandon their feeding binge. Winter killed, carrion is an important food source for bears that are recently out of hibernation and in need of protein and nutrition. Note the two carcasses and the size and white color of his claws.
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A young and relatively small competitor
This is one of the youngest and smallest bears that I witnessed during the several days of photographing the carcasses. The large dominant males tolerated this smaller bear; he was never attacked or harassed. He did however make way when the dominant males came to feed. This young bear was able to partially hoist the soaking monstrous carcass from the river in order to access the most nutritious parts. These carnivores are incredibly powerful.
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A dominant male grizzly bear (Ursus arctos horribilis)
This dominant boar was also unchallenged. He enjoyed free reign over the carrion and would stand feasting in the frigid river for hours on end.
Ursus is Latin for bear, arctos is Greek for bear, and horribilis is from the Latin meaning gruesome and dreadful. Note the size and brown color of his claws.
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Bald Eagles had opportunities as well
Dominated by bears, bald eagles (Haliaeetus leucocephalus) greedily feasted on the bison carcass while the bruins were resting. They would flap their massive wings to generate the force necessary to separate flesh from the carcasses. Haliaeetus leucocephalus has it’s origin in Greek as follows; hali = sea, aiētos = eagle, leuco- = white, cephalos = head. Very simply translated to (white headed sea eagle).
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Two bears disagree
On one occasion, two bears that I observed peacefully sharing the carrion had a brief and seemingly inconsequential disagreement. Once the argument was settled, they quietly resumed feeding.
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Each bear had unique feeding and scavenging techniques
This bear would stand on the carcasses and rock them to and fro in an effort to expose choice parts. Each bear had it's own methods for manipulating and accessing the carrion.
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Most bears preferred eating the head
During the initial feeding period while the carcasses were mostly in tact, every bear that I observed feeding consumed head flesh first. I presume that the bears were instinctively seeking out the most nutritional part of the carcass. I would assume that the head flesh was tender and delicious as well. Note his exposed monumental canine teeth.
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My favorite bear
This old grizzled boar with white claws and light patch on his neck was my favorite bear. His every move was deliberate, he was dignified, and he seemed to be totally fearless.
grizzly bear yellowstone national park wyoming mammal wildlife