 the steller's sea cow (hydrodamalis gigas) was a large, herbivorous marine mammal. it was the largest member of the order sirenia, which includes its closest living relative, the dugong (dugong dugon), and the manatees (trichechus spp.), and "other than the great whales, likely the largest mammal to exist in historic times". although the sea cow had formerly been abundant throughout the north pacific, by 1741, when it was first described by georg wilhelm steller, chief naturalist on an expedition led by explorer vitus bering, its range had been limited to a single, isolated population surrounding the uninhabited commander islands. within 27 years of discovery by europeans, the slow-moving and easily captured steller's sea cow was hunted to extinction. ==description== thumb|left|skeleton in finland the sea cow grew to at least  in length as an adult, much larger than the manatee or dugong; however, concerning their weight, steller's work contains two contradictory estimates: 4 and 24.3 metric tons. the true value is estimated to lie between these figures, at around 8 to 10&nbsp;t.{{cite journal |last=scheffer |first=victor b. |title=the weight of the steller sea cow |journal=journal of mammalogy |volume=53 |issue=4
Extinct_animals_of_the_United_States Extinct_mammals Extinct_mammals_of_Asia IUCN_Red_List_extinct_species Mammal_extinctions_since_1500 Megafauna Sirenians Species_made_extinct_by_human_activities