The main direction of the evolution of the bear family is omnivorous, common to all its members. However, in the history of bears are known cases of evasion of the total evolutionary line that created unique animals. One of these branches is Amphicynodontinae subfamily, early separated from the general bearish tree, evasion which in food preferences to feeding marine invertebrates gave rise to the world Kolponomos - one of the most unusual of the Ursidae family , whose lifestyle made it a very similar to otters.
Kolponomos are known finds of skulls and skeletal elements from the Early Miocene deposits of the west coast of North America. Now distinguish two species - K. klallamensis and K. newportensis. Initially Kolponomos was questionably added to Procyonidae. However, these animals has long remained enigmatic genus, them found it difficult to firmly identify in any of the families of the Carnivora order. But further findings and their detailed analysis allowed to define a Kolponomos to Amphicynodontinae, which belongs to the bear family was defined common with other bears in the basicranial structure and the strong development of the mastoid area of the skull.
Skulls of Kolponomos an average of about a quarter of a meter, they were big animals, at least not inferior in size Amazonian giant otters. The whole cranial morphology shows the commitment of animals to an semi-aquatic life. Broad nasal opening is located quite high - probably nostrils of Kolponomos open up like in seals. Infraorbital and mental foramens, in which to lips outlet tufts of blood vessels and nerves, is a very broad - they probably indicate increased tactile sensitivity of lips and muzzle. Kolponomos could also have a big upper lip, as in modern walrus, which were developed brush densely planted sensory vibrissae, helping to find food on the bottom. He ate, according to a broad, flattened and heavily worn chewing tooth, shellfish and crustaceans whose hard shells had to bite. Eye sockets facing forward, not to the sides, like in modern bears - Kolponomos, probably, could consider objects that lie directly in front of his face. This would have the benefit to the animal, which selectively feeds demersal marine invertebrates. From the back of the skull are well developed large paroccipital and mastoid processes for securing the strong neck muscles. Upper canines and incisors are large, they clustered on the leading edge of high maxillary, rostrum noticeably bent down - probably so, like forceps jaws are adapted for better grip and tear clamshell that entrenched on the rocky bottom. In the course were strong neck muscles that could have provided strong downward movements of the skull.
Unfortunately, the skeletons kolponomosov found very little, but because of the proportions of their bodies can only guess. General anatomy of known skeletal remains combines traits of both pinnipeds with otters and terrestrial predators. Limb bones indicate that Kolponomos were not exclusively aquatic animals like pinnipeds, but to move freely in the water and on land. Only found phalanx has large side wings to the flexor tendons, implying active movement strong fingers when handling the prey. At least from Amphicynodon, one of Amphicynodontinae, restored skeleton - this animal had a long tail and an elongated body. Probably kolponomos had more or less similar proportion, which made him look like an otter.
In general Kolponomos is adaptive analog of sea otter, despite some differences in the way of getting food, because sea otters do not use their teeth to capture prey from the bottom. Obviously, kolponomos lived on the coast, occasionally diving into shallow water for prey. All known specimens are found in shallow coastal sediments that contain abundant fossilized shellfish, including large mussels and giant pectinids, ensured these "otter-bear" food.