The Northwest Native North American Cultural area has a confusing situation in regards to representing Sea monsters and Sea serpents, which are confusingly not internally discriminated and casually called by the names of each other. This is a depiction of a Sea Wolf feeding on small whales (evidently pilot whales) in the form of a Sea Wolf (Haida Wasco) but it is mislabeled as a Sisutl. The type of sea serpent that is being represented is otherwise a Marine Saurian and described as a "Sort of an Alligator" while the real Sea Wolf would seem to be a smaller furry animal otherwise called a Sea Dog and evidently a kind of a big otter. However in this case we are interested in this image as depicting a whale-eater. It would seem from the depiction of the whale above the creature's head that the head is fifteen feet long and possibly it has a kind of a fin at the back of the head. it has a basically lizard-shaped body and has an especially large, long and heavy tail, with which in this case it has captured a whale and is holding onto it prior to eating it. This is emphasized in tradition and so This could be true. This would be the larger sort of Marine Saurian and reliably stated to be a hundred feet long or more although a good stretch of that length is the long and powerful tail. Most likely it is a persisting Mosasaur adapted to feeding on small whales and so it was continually getting bigger as the whales it fed on likewise got bigger during the long periods of the Age of Mammals.