Sirenia (Dugongs and manatees)

There is some discussion over how many groups of marine mammals there are. Some organizations say four; others say five. They all include the same mammals, so I wanted to research what these are. NOAA recognizes four different groups: cetaceans (whales, dolphins, and porpoises), pinnipeds (seals, sea lions, and walruses), sirenians (manatees and dugongs), and marine fissipeds (polar bears and sea otters). The Marine Mammal Center separates …

North American manatees are the same species as the West Indian manatee.   The manatee in North America is the largest member of the aquatic mammal order Sirenia. The North American manatee is a species distinct from the Amazonian manatee and the African manatee. Recent genetic research suggests that the West Indian manatee consists of three …