Both manatees and dugongs are classified in the order Sirenia. They are both slow-moving herbivores (mostly) that can be found in areas of shallow waters along warm coastlines.
There are four living species of Sirenia – the West Indian manatee, the Amazonian manatee, the West African manatee, the dugong and the extinct Stellar’s sea cow (hunted to extinction in the 18th Century). They are all found in different areas, so depending on where you are, you will know what you are looking at!
They’re NOT the same creature with a different name!
So what’s the difference between manatees and dugongs?
Habitat – where will you find them?
Manatees inhabit the marshy areas of the Caribbean and Gulf of Mexico (West Indian Manatee), the Amazon Basin (Amazonian Manatee) and West Africa (West African Manatee). Dugongs spend their entire life in shallow, protected areas such as bays and mangrove swamps (they can be found in places like Bazaruto / Vilanculos in Mozambique and Marsa Alam in Egypt) as well as the waters off northern Australia. We were so lucky to have seen one in Marsa Alam, Egypt recently – what an incredible creature, so serene.
Manatees have a large, horizontal, paddle-shaped tail with only one lobe, which moves up and down when the animal swims. Dugongs have tail flukes with pointed projections, like a whale with a slightly concave trailing edge.
West Indian and West African manatees have very basic nails on their forelimbs. Amazonian manatees and dugongs don’t have any nails.
The nostrils of a dugong are placed further back on its head than in the case of manatees.
The angle of the dugong’s mouth is more pronounced than that of the manatee. It has a short, broad, downward facing trunk-like snout that is horseshoe-shaped with a slit-like mouth with an undivided upper lip. Because of this they are bottom-dwelling. Manatees have a divided upper lip and a shorter snout which means they are able to gather food to eat and are also able to feed on plants growing at or near the surface of the water.
Mature male dugongs have a pair of tusk-like incisors and manatees do not. Manatees have no incisors, only cheek teeth (molars) which are continuously replaced – its molars move forward in the mouth, stimulated by the chewing motion, towards the front of its jaw until it falls out at the front. As the teeth move forward, they are replaced by new ones at the back – rather like a conveyer belt! They usually have no more than 6 teeth in either jaw at any one time. The two rear molars in dugongs are open rooted which means as they are worn away, they just continue to grow!
Manatees are generally solitary creatures and a male manatee may have several female partners; whilst dugongs are more solitary and tend to live in pairs and have only one mate. The Dugong we saw in Marsa Alam was one of a pair that visited the bay quite often. Apparently there was a baby living in the next bay along – one to look out for!
Female manatees usually give birth at 3 years and continue to do so every 2 – 3 years. Their gestation period is 12 months. Female dugongs usually only give birth at 10 years and usually only every 3 – 5 years after that. Because of their long lifespan (70 years) and slow rate of reproduction, and because dugongs continue to be hunted in Africa for their blubber and meat, they are IUCN’s list of being vulnerable to extinction.
Dugong with calf
Manatee with calf
Manatees are generally larger than dugongs and can weigh between 400 and 500 kg and grow to a length of 3.6 metres. Dugongs rarely grow larger than 3 metres and weight is, on average 420 kg.
So, now you know more about these beautiful creatures, let’s go and find them 😀
Manatee Photo http://en.wikipedia.org/wiki/File:FL_fig04.jpg
Dugong and mother: http://en.wikipedia.org/wiki/File:Dugong_mother_offspring.jpg
Manatee and mother: library.thinkquest.org