Kodiak bear is the largest subspecies of brown bear in the world, and rivals the polar bear as the largest terrestrial carnivore. It can reach a height standing on its hind legs of 2.5–3.2 m. Scientists counted about 3,000 kodiak bears, excluding the population in the Kodiak Archipelago.
The weight varies considerably: in the spring period when they come out of hibernation they have a dry muscle mass, while in view of autumn they increase their weight by up to 50% by accumulating fat reserves which are essential during hibernation.
Females have an average weight of 270-360 kg, mature males reach 450-550 kg, the largest specimens and close to hibernation can weigh 640 kg, or even more. The body is particularly robust, with a massive head, often emphasized by a crown of long hair which makes it even more imposing, and small ears.
The fur is long and generally of a uniform dark brown color, more similar to that of the European brown bear than to that of the grizzly, often tending towards reddish, however it can vary considerably from individual to individual.
The current classification tends to consider most of the population of brown bears of the coastal regions of Alaska as belonging to the species Ursus arctos middendorffi, distinguishing them from the grizzlies, widespread on the continent.
However, the common name Kodiak is often used in a more restricted sense to indicate the bears of the Aleutian Islands while the brown bears of the forests further east are often defined as grizzlies like their southern relatives.
The affinity between the two subspecies, which often occupy the same territories and have similar habits, actually makes a precise classification difficult. If the bears living in the Aleutian archipelago can undoubtedly be defined as kodiak, those of the mainland are less clearly definable, often presenting intermediate characters between the bears of the islands and the Canadian grizzlies.
Generally the kodiaks are identifiable by the less pronounced hump, the uniform coat and the thick and long fur around the head. Like all bears, it has an omnivorous diet, but with a greater tendency to feed on meat, thanks also to the high number of preys available, revealing itself as a rather skilled hunter, capable of attacking even large animals such as moose and deer.
A skilled fisherman, in the autumn he usually feeds on the salmon that swim up the rivers, the presence of which is the basis of the great diffusion of bears in the region. Aside from feeding attacks, it appears to have a quieter and less aggressive temperament than Rocky Mountain grizzlies.