The Dugong (Dugongidae) is the only strictly herbivorous marine mammal. It is one of four living species of the order Sirenia, which also includes three species of manatees. The Dugong is the only living mammal of the once-diverse family Dugongidae. Its closest relative, the Steller’s sea cow (Hydrodamalis gigas), was hunted to extinction in the 18th century. Dugongs and other…