Genetic research tells us there are two forms of brown bear in North America, the Kodiak bear (U.a.middendorffi) and the grizzly bear (U.a.horribilis) replacing the older geographical taxonomy classification of brown bears. Bear enthusiast will be familiar with the popular Yakutat geographical taxon Ursus arctos dalli.
Mature Alaska Peninsula male brown bears will average 1000 lbs. Later in the year this forum will examine relating morphological data. FWIW, their brown bear cousins from the Kodiak archipelago (i.e., mature males) get pretty big too (ditto for Kodiak brown bear data).