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Manatee Relatives

Manatees on Land?
Manatees seem so perfectly designed for their slow, gentle life in the water. But can you believe they weren't always that way? Can you believe that once, long ago, the manatee's ancestors were land animals?

It's true. Manatees and their closest relative, the dugongs, are in the Order Sirenia. The term "Sirenia" is derived from the word "siren" which refers to mermaid-like creatures that stories say the sailors of long ago saw at sea (including Christopher Columbus.)

Despite their name, and despite having some similarities to the general body shape and habitat of other marine mammals (like sea lions, walruses or dolphins), manatees are not related to other marine mammals at all. Scientists say there is no "evolutionary relationship" between manatees/dugongs and marine mammals.

Don't Forget the Ungulate
So what other species did manatees evolve from? It is believed that manatees and dugongs evolved from four-footed land mammals over 60 million years ago, and some scientists believe Manatees evolved from a wading, plant-eating animal. Believe it or not, but the manatee's closest living relatives are actually three land animals which include the elephant,the hyrax (a small, gopher-sized mammal), and the aardvark!.


Credit: Credit: FWC

Credit: University of New Mexico

These four species--manatees, elephants, hyraxes and aardvarks--are referred to as "subungulates", meaning they all evolved from a primitive "ungulate" ancestor. An "ungulate" refers to a hoofed mammal, and includes the species in the former order ungulata, such as horses, cattle, deer, swine and elephants. Their common evolutionary background has been studied using biochemical analysis of proteins.

The earliest animal that had a manatee-like appearance is thought to be the Potamosiren, which dates from about 15 million years ago. At that time, that animal did not have the continual tooth replacement adaptation.

Try This! Journaling Questions:
  • Although the manatee is related to the elephant and hyrax and the aardvark, they are quite different animals. Think about all the parts and functions of each species' body, and then compare and contrast them. What similarities are there? What differences are there?
  • Who are your family relatives? Do you look like them? How? In what ways are you different? In what ways are you similar?