Structure and Distribution of a Kodiak Bear Population

Population characteristics of the Kodiak bear (Ursus middendorffi) were investigated in the Karluk Lake drainage, a 96-square-mile area within the Kodiak National Wildlife Refuge. The drainage contained 160 bears, for a density of 1 bear per 0.6 square mile, although some areas attained concentrations of 10 bears per square mile. The mean litter size for cubs was 2.36 and 2.17 for yearlings. Age-class percentages were: cubs, 26; yearlings, 22; 2 years, 17; 3 years, 10; and bears 4 years old and over, 25 percent. The sex ratio was relatively even in the younger age-groups, but in adults, females constituted 78 percent. This was attributed to selective hunting for larger males.