The Steller's Sea Ape is a marine cryptid described only from a single sighting by explorer George Wilhelm Steller, on August 10, 1741, in waters off the Shumagin Islands, Alaska.
Steller described the animal as about 5 ft (~1.5 m) long, with a head similar to that of a dog. It had large eyes, pointed and erect ears, and long whiskers. Its tail resembled that of a shark, but it had no forefeet nor forefins. Its body was covered with thick grayish hair, but its abdomen was reddish-white. Steller recalled that it resembled an animal illustrated by Gesner which had been called Simia marina, Latin for "sea ape".
ExplanationAccording to biographer Dean Littlepage, a young Northern fur seal (Callorhinus ursinus) appears to be the most likely explanation for the sighting. Their forelimbs are set far enough behind on their torso so that they could have been obscured below the waterline, and the "shark-like" tail of the creature may have been the animal's hind flippers. Steller had already been familiar with fur seals, but Littlepage suggests that the poor lighting conditions during the lengthiest encounter of a probable juvenile fur seal could account for the misidentification.
Another explanation that the sea ape might be a congenitally malformed fur seal.