Steller’s sea cow was a large herbivorous marine mammal. In historical times, it was the largest member of the order Sirenia, which includes its closest living relative, the Dugong and the Manatees. Formerly abundant throughout the North Pacific, its range was limited to a single, isolated population on the uninhabited Commander Islands. Steller’s Sea Cow was first described by George Wilhelm Steller, chief naturalist on an expedition led by explorer Vitus Bering in the year 1741.
Steller’s Sea Cow could grow up to 28 feet long, and weigh as much as 7-8 tons. Drifting just below the surface, they were often mistaken for overturned boats. With a heavy bone structure, they had huge midsections, a disproportionately small head, and a large, flat, twin-lobed tail. The wrinkly black hide was about an inch thick and very tough, covering a fat layer between 4 and 9 inches thick – the combination provided protection from the cold, pounding by surf, and rubbing against ice and rocks. It did not provide sufficient protection from weapons. Only one out of five sea cows hit by harpoon or rifle fire was retrieved and the majority escaped only to die at sea from their injuries. Within 27 years of discovery by Europeans, the slow moving and easily captured Steller’s sea cow was hunted to extinction.