, a subspecies of the brown bear, once roamed the Great Plains and across much of western North America. After Europeans began colonizing the New World, though, human expansion gradually pushed lower 48 grizzlies into ever more remote wilderness regions, where perhaps 1,400 survive today.
Most of the grizzly populations in the lower 48 are listed as threatened under the U.S. Endangered Species Act, but they remain numerous in Canada and Alaska.
Global warming may cause human-bear conflicts--which often end badly for the bears--to rise, the December 2009 report says. As shifting temperatures shorten hibernation seasons and make natural food sources, such as pine seeds, scarce, the bears may spend more time looking for meals in human territory.
Photograph by Karen Kasmauski, National Geographic Stock