The incident occurred approximately 2.5 miles from the Pelican Valley Trailhead in the Pelican Valley Bear Management Area. The national park says he began to deploy bear spray before the bear made contact, injuring his chest and left arm. The hiker thought the bear was a black bear; however, the location, size, and behavior of the described bear suggest it might have been a grizzly bear. Bear management staff will attempt to confirm the species through DNA analysis, if possible. Yellowstone National Park Officials Caution -- Be bear aware to help avoid surprise bear encounters:Carry bear spray and know how to use it.