Despite deaths, grizzly population grows The number of grizzly bear deaths in the greater Yellowstone ecosystem increased markedly this year, but the population still continued to grow. According to the Interagency Grizzly Bear Study Team, an estimated 80 grizzlies died in the Yellowstone area in 2008. In 2007, 49 grizzlies died. The numbers of grizzly deaths are estimated from known, probable, estimated unknown and unreported deaths from a variety of causes, according to Interagency Grizzly Bear Study Team figures. Despite the deaths, the grizzly population in the ecosystem increased an estimated 4 percent this year. In 2007, there were an estimated 571 grizzlies. In 2008, the number increased to an estimated 596 grizzlies. Based on those figures, the population will double in 20 years, said Chuck Schwartz, Interagency Grizzly Bear Study Team leader in Bozeman, Mont....