This incidence reminds me of Timothy Treadwell who was avid grizzly enthusiast, living closely to bear habitat in Alaska more than 10years. Unfortunately, he and his wife ended up being killed by one of the grizzly bears that might consider Treadwell as prey. I remember watching him on the Discovery channel approaching bears and teasing them with bushes or stones. It might be that this Wyoming incidence is human's fault while we are invading their area and do not leave them alone. We are still planning to hike trails in the beautiful Wyoming, of course with bear sprays and poles, hoping that we never have to use any.