It's all about the fingernails[l1] . Don't worry, we're not talking about getting a pre-dive manicure, we're talking about how to differentiate a dugong from a manatee. While both are commonly referred to as 'sea cows,' dugongs and manatees are different species, and if you happen across one without fingernails, chances are it's a dugong. Both manatees and dugongs belong to the taxonomic order Sirenia and, although different species, share many similarities. With links to mermaid myths and family ties with elephants, the Sirenia are an interesting biological order, and we're going to run through the top ten dugong/manatee facts to help you get to know these docile creatures...
1. Dugong and Manatee: Not the Same Species
There are four living species in the order Sirenia, with one species of dugong and three species of manatees. The three species of manatee are the West Indian manatee, the African manatee and the Amazonian manatee. Aside from their differing locations, one way to tell the species apart is to see if they have fingernails. Dugongs and Amazonian manatees do not have fingernails, while the West Indian and African manatees do.
You can also differentiate between dugongs and manatees by checking out their tails (or flukes). The fluke of a dugong is notched and similar to those of dolphins, while the tail flukes of manatees are a smoother paddle shape.
2. Are Dugongs Mermaids?
There have long been stories of dugongs and manatees being the inspiration behind the mermaid myth. This is in part fuelled by the popular misconception that the word dugong is derived from the Malay word duyung, which means 'lady of the sea.'
It has become accepted that the word dugong actually derives from a Visayan word, dugung, from the Philippine island of Cebu and also has links to the Proto-Malayo-Polynesian word duyuŋ.
3. Where Do Dugongs Live?
While they are similar creatures belonging to the same biological order, dugongs and manatees live in different areas of the world. Dugongs (Dugong dugon) prefer warm waters close to shore, and can be found along the eastern coast of Africa, including the Red Sea, across the western Pacific to the Philippines, Palau and Indonesia.
4. Where Do Manatees Live?
Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea and the Gulf of Mexico, with the three extant species having largely separate ranges. The clue is in their name, with the African manatee (Trichechus senegalensis) inhabiting much of western Africa, from Senegal to Angola.
The West Indian and Amazonian manatees have ranges that slightly overlap, but the Amazonian manatee (Trichechus inunguis) is more prevalent in the Amazonian basin's river network than the coastal waters of Brazil. The West Indian manatee (Trichechus manatus) lives in the shallow waters between Florida and the north-east coast of Brazil, including much of the Caribbean Sea.
5. Where to Dive with Manatees and Dugongs
If you would like to see either dugongs or manatees underwater, there are a few locations where the odds will be in your favour. For dugongs, African destinations like the Red Sea and Tanzania are good options, as well as Bunaken National Park in Northern Sulawesi, Indonesia, Coron in the Philippines and Palau.
For manatees, Florida is the place to go to see these buoyant beauties, as well as the Yucatan Peninsula in Mexico, stretching down the Caribbean coastline to Belize.
6. What Do Manatees and Dugongs Eat?
All four living species of dugong and manatee are herbivores, with a particular penchant for seagrass. Consequently, you will often see them on sandy seagrass beds, where, true to their 'sea cow' nickname, they spend much of their time grazing. An adult manatee will commonly eat a whopping 50 kilograms per day..
African manatees and dugongs are also known to supplement their vegetarian diets with fish, molluscs, and jellyfish.
7. How Big Are Manatees and Dugongs?
Of the four species of Sirenia, the African manatee is the largest, reaching up to four-and-a-half metres in length, while the Amazonian manatee is the smallest, reaching a little under two-and-a-half metres in length.
If you're diving in the Caribbean, you may spot a West Indian manatee, which can reach up to three-and-a-half metres, while visitors to Eastern Africa or Asia could meet a dugong measuring up to three metres from snout to fluke.
8. Dugongs and Manatees Are Related to Elephants
Dugongs and manatees are more similar to elephants than marine animals and are the only herbivorous mammals to have become completely aquatic. Aside from having skin similar to an elephant's, the top lips of the Sirenia also bear a resemblance to an elephant's trunk, albiet much shorter. Manatees in particular have large, flexible, prehensile upper lips, which they use to gather food in much the same way that an elephant does.
9. Their Predecessors Were Bigger!
The now-extinct Steller's sea cow (Hydrodamalis gigas), a member of the Sirenia order, once roamed the Bering Sea. First described by German explorer Georg Wilhelm Steller in 1741, Steller's sea cows reached lengths of up to nine metres and weighed up to ten tonnes! Unfortunately, they were hunted to extinction and disappeared in the second half of the 18th century.
10. Manatee and Dugong Conservation
Both manatees and dugongs are cited as being 'vulnerable' on the IUCN Red List of Threatened Species. Unfortunately, the main threats to their existence come from humans, with habitat loss and coastal development being chiefly to blame.
However, there is light to this dugong/manatee fact as both dugongs and manatees have been afforded protection by the US Marine Mammal Protection Act of 1972, the US Endangered Species Act of 1973, and the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES). There are also conservation groups, such as the Dugong and Seagrass Conservation Project and the Save the Manatee Club, working to help protect them and their environments.