The victim, Lance Crosby, was found mauled to death Friday.
DNA evidence confirmed that the bear was the one responsible for the attack, the park said.
The park said a part of the decision to euthanize the bear "was that a significant portion of the body was consumed and cached with the intent to return for further feeding," the park said in a release today.
"Normal defensive attacks by female bears defending their young do not involve consumption of the victim’s body."
The park also said that they were considering "the long term viability of the grizzly bear population as a whole, rather than an individual bear,” the statement said.
Crosby worked for a company that runs urgent care clinics in the park, Yellowstone said. The park confirmed today his death was a result of traumatic injuries from a bear attack.