The Steller’s sea cow (Hydrodamalis gigas) was an extinct sirenian first described in 1741. Its closest living relatives are the dugong and the manatee, though it far surpassed them in size. The species was wiped out by humans less than 30 years after its discovery. | Colossal Biosciences

Steller's sea cow (Hydrodamalis gigas) is an extinct sirenian described by Georg Wilhelm Steller in 1741. | Ron Aldo

The Dugong, or “Sea Cow”, is a herbivorous marine mammal that is the last representative of the once-diverse family Dugongidae. The closest modern relative, Steller’s sea cow (Hydrodamalis gigas), was hunted to extinction in the 18th century. | Science Channel