Three more human-caused grizzly bear mortalities are under investigation in the Greater Yellowstone Grizzly Bear ecosystem. The Montana Fish, Wildlife and Parks Department reports that one mortality occurred Saturday afternoon in Eureka Basin in the south Gravelly Mountains southwest of Ennis, Montana when a hunter reportedly shot the bear in self-defense. Details of the incident are still under investigation. Three hunters were attacked in two separate incidents in the western Gravellies in September. The U.S. Forest Service shut down several trails in region due to a high number of grizzly bears in August. But later reopened them. Montana Fish, Wildlife and Parks also reports that they, along with the US Fish and Wildlife Service are also investigating two other human-caused grizzly bear mortalities that happened last week in the West Yellowstone area. Agencies throughout the ecosystem are cautioning that the bears are very active now as they prepare for the winter. Commuters on Teton Pass recently posted video of a grizzly sow and a cub walking in the road there.