Although Kodiak and Polar bears are both bear species, they are different in many aspects. The Kodiak bear is a subspecies of the Brown Bear. In fact, it is the largest subspecies of them. Typically, they get much bigger than other Grizzlies, because they have an abundance of Pacific Salmon to consume. They are only found on Kodiak Island, which is off the southern coast of Alaska. They try to avoid any and all contact with humans.
The Polar Bear, on the other hand, is even larger than the Kodiak Bear. They are a direct descendant of the Brown Bear and are now classified as the largest bear on the entire planet. Although they are usually more slender, they are definitely longer and therefore, stand taller. Not only that, but they are now classified as a marine mammal because of the large amount of time that they spend in the water. In fact, they spend months and months of the year out at sea.
Polar bears are social animals. However, whenever they are hungry they will kill almost anything to have something to eat. The most common thing they attack and consume are seals. They have also been known to hunt walrus and beluga whales. They are mostly concentrated within the Arctic circle which encompasses the Arctic Ocean. They can also be found around surrounding land masses.
Kodiak bears are generally solitary animals and are more aggressive than Polar bears are. However, Polar bears are more experienced when it comes to killing extremely large prey. If you were ever to pit these massive species against each other, it could be a toss up as to who would win. They come from very distinct backgrounds, and therefore, they each have different advantages.
If they ever attacked each other, the polar bears would get the first hit. They have longer arms and a longer neck, so it would give them the first benefit. The Kodiaks are likely to avoid fatal injury, though, because they have many layers of fat. The Kodiak would then retaliate. They have a lot of experience in territorial fights with other big bears. They also have lots of strength and weight to use to their advantage. More than likely, the Kodiak's would charge the Polar Bears and knock them down. It would not be likely that the Polar bear would ever be able to get back up. So, in the end, they would probably lose the fight.