Manatees and dugongs – same difference, right? And no quick Google image search is going to change that perspective – after all, they look alike. But in fact, the two living mammal species that belong to the sirenian animal order are oceans apart in terms of location, biology and behaviour.
They’re classic chalk and cheese: both slow-moving herbivores that operate in similar ecosystems with similar looks and similar builds, but to the trained eyes of those who know, they have many different characteristics. There are four living species of Sirenia – the West Indian manatee, the Amazonian manatee, the West African manatee and the dugong – all referred to as “sea cows” and each found in a different area.
To understand their differences deeper, we take a look at the main, but subtle, points that separate these creatures:
Tails
Both creatures are related to the elephant, but evolution has played a part in redefining their tails to be more efficient underwater. One of the main physical differences between the dugong and manatee is the tail: Manatees have a horizontal, paddle-shaped tail with only one lobe to move up and down when the animal swims; it’s similar in appearance to that of a beaver tail. Dugongs have tail flukes with pointed projections, like dolphin or whale tails but with a slightly concave trailing edge.
Socialising
With different characteristics, it appears that manatees are the more outgoing out of the two. Both are solitary creatures, but manatees are devout polygamists – having up to several female partners. Dugongs, however, stick to just the one, which they live with for life.
Dugongs
Scientific name: Dugong dugon
Diet: Herbivore
Average lifespan: 70 years
Size: 2.4 – 3 metres
Weight: 230 – 500 kilograms
Dugongs are large marine mammals that are found near coasts around the Pacific and Africa. They spend most of their lives grazing on underwater grasses, rooting for them with their bristled, sensitive snout which acts as a sub-aqua hoover. Unfortunately, due to their docile behaviour, they are easy prey to illegal hunters, and their population has been heavily reduced.
Offspring
Female manatees usually give birth at three years and continue to do so every two to three years. Their gestation period is 12 months. Female dugongs differ in that they usually give birth at 10 years and only every three to five years after that. This is mainly due to their long lifespan and slow rate of reproduction.
Mouth
Dugongs have short, broad, downward facing trunk-like snouts that are horseshoe-shaped with a slit-like mouth. The snout ends with a cleft, a muscular lip that aids the dugong in its foraging for seagrass – because of this it is a strictly bottom-dwelling feeder. Manatees have a divided upper lip and a shorter snout, which means that they are able to gather food to eat and also able to feed on plants growing at or near the surface of the water.
Manatees
Scientific name: Genus Trichechus
Diet: Herbivore
Average lifespan: 40 years
Size: 2.4 to 4 metres
Weight: 200 to 600 kilograms
Manatees are voracious herbivores found throughout the Caribbean, the Gulf of Mexico and Africa. Their diet consists mostly of plants like mangroves, turtle grass and some algae. Despite their massive bulk, they are graceful swimmers in coastal waters and rivers.
Habitat
Manatees inhabit the marshy areas of the Caribbean and the Gulf of Mexico (West Indian manatee, Trichechus manatus), the Amazon Basin (Amazonian manatee, Trichechus inunguis) and West Africa (West African manatee, Trichechus senegalensis). Dugongs spend their entire life in shallow, protected areas such as bays and mangrove swamps as well as the waters off northern Australia. Manatees generally live in fresh water, whereas dugongs can usually be found in marine environments.
Nails
West Indian and West African manatees have fingernails – albeit very basic ones – on their forelimbs. But Amazonian manatees and dugongs do not have any nails.
Teeth
Mature male dugongs have a pair of tusk-like incisors and manatees do not. In fact manatees have no incisors, only molars which are continuously replaced. The teeth of manatees move forward like a conveyor belt: As the tooth comes forward from the back, another tooth then takes its place.
Nostrils
A dugong’s nostrils are further back on its head than they are on a manatee. Both are specially designed for being submerged in water. For the dugongs their nostrils act like valve openings on top of their heads, which open when they breach for air, and close when underwater.
Find out more about manatees HERE.
Alan Lo is a commercial photographer based in Hong Kong. He expresses his passion for the underwater world through his multifaceted approach to photography, which is grounded in his innovative and artistic interpretation of life, people and Nature. Alan’s work has evolved and progressed significantly over the last 20 years, from his early creative print work and exhibitions, through a range of architectural commissions, commercial projects and personal photographic explorations. 
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Amos is a master of photographing big animals worldwide. For 35 years, he has explored every body of water from the North Pole to Antarctica. Amos’s photographic vision is to raise awareness of ocean giants in their habitats. His images reflect respect and compassion for animals and wilderness and strive to dispel the myth of “dangerous” wildlife and show harmonious interactions between man and animal.
Gary Sun is a long time diver who has been taking underwater photography for many years, whose works has won many awards and published in numerous magazines and newspapers. He is the Director of Guangdong Photographers Association Underwater Photography Committee and the Standing Director of Guangdong River Ocean Ecological Environment Protection. He is also China’s first RAID closed circulatory and respiratory systems instructor trainer officer, as well as a NAUI Diving Instructor.
Michael Aw is an author, explorer and conservation photographer. His accolades include winning more than 63 international photographic awards including being named as one of the world’s most influential Nature photographers by Outdoor Photography, and in 2013 he was the first Asian to be awarded a NOGI by the American Academy of Underwater Arts and Science.
Yorko Summer is a Taiwanese certified dive instructor and travel journalist who has visited many countries and exotic islands. Being an underwater photographer, he loves to spend time taking photographs from the unique and amazing underwater world, as well as the vast culture around the world. He has lived in the exotic island of Palau for six years, where he fell in love with the mysterious, yet elegant, oceanic world and its inhabitants.
Zhou Qinan is a video culture media founder, senior director and an underwater videographer. Being an expert in image narration, he emphasises strongly on content, rhythm and music, thus his works are affluent and powerful. For eight years, the Scorpio director’s “obsessive-compulsive disorder” and perfectionist personality have reflected most vividly in his lens insights. Most of his works create a connection with people, using “love” as his directing style in filmography.
