An adult male polar bear (Ursus maritimus) on melting summer sea ice with the body of a young bear (a yearling cub, about 19 months old) he killed for food, in Olgastretet in the Barents Sea (Arctic Ocean), within the Svalbard Archipelago. I first observed the adult male bear on an ice floe from a considerable distance away. I could see that he had a fresh kill, and eventually I realized his prey was a yearling cub. The blood on the dead bear was very fresh and still flowing, the body was limp, and the young animal appeared to have just died. The cub had been severely bitten in the head, in the same manner of attack that a polar bear would use to kill a seal. As my boat began to approach, the adult male bear initially continued feeding on the cub and looked up at the boat occasionally. When I got closer, he straddled the young bear's body and stood stiffly over it, adopting a possessive posture that strongly communicated his control of the kill. He stared directly and continuously at my boat, as if to assert the warning "this is MY food." Then he grabbed the back of the cub's body in his teeth, and moved away quickly – transporting the carcass with him using only the power of his jaws and neck while running across the ice, climbing over pressure ridges, and swimming from floe to floe in an impressive display of strength. Ultimately, when he was again a considerable distance away, he resumed feeding on the cub's body. Based on my observations and all the surrounding circumstances involved, it was clear the adult male had killed the young bear specifically in order to eat it. Such incidents are rare; however, as the Arctic sea ice polar bears depend upon for hunting seals continues to disappear due to climate change, scientists believe that intraspecific predation such as this may become more common.