Imagine you’re a sailor aboard a merchant’s vessel in the late 1700s. One day during a voyage in the West Indies, you look down into the water and see a smooth-bodied animal glide under your boat. You blink and rub your eyes, not trusting your vision. You look again and catch a glimpse of a tail in the water before losing sight of the mysterious creature. Given this scenario, it’s easy to see why early sailors and explorers thought that they saw mermaids on long expeditions. Today, we know that the creatures these men saw were most likely manatees or dugongs. Also known as sea cows, these large aquatic marine mammals spend most of their days floating through brackish water in search of sea plants. They both belong to the order Sirenia and look similar to one another. However, several distinguishing features can help you identify a dugong vs manatee.
In this article, we’ll compare the size, habitat, appearance, and behavior of a dugong vs manatee. At the end of the article, we’ll also answer several frequently asked questions concerning dugongs and manatees to help resolve any lingering confusion. Here are 9 key differences between dugongs and manatees.
Comparing Dugongs and Manatees
|Up to 13.32 feet
551 to 2,240 pounds
|Up to 15.1 feet
800 to 3,913 pounds
Shallow, coastal waters including bays, harbors, and mangrove channels
|The Caribbean, Gulf of Mexico, Amazon Basin, and West Africa
Marshy coastal areas and rivers
Saltwater and freshwater
|A wide, short trunk that points downward
Divided upper lip
|No canines, but replace molars throughout life
|Fluked, dolphin-like tail
|Paddle-shaped, beaver-like tail
|West Indian and African manatees have fingernails
|Diet and Feeding
|Seagrass and some invertebrates
Use lips and teeth to rip out plants
|Sea and freshwater plants and algae
Use flippers to walk along the bottom and scoop food toward the mouth
|Mating and Reproduction
Females give birth around 10 years old
Females give birth around 3 years old
The 9 Key Differences Between Dugongs and Manatees
Dugongs and Manatees: Size
One of the most noticeable differences between a dugong vs manatee is their respective size. On average, manatees grow longer and heavier than dugongs, although individual dugongs can grow bigger than most manatees. The average length of a dugong is around 9.8 feet, although wild specimens can reach up to 13.32 feet. While they generally weigh between 551 and 1,984 pounds, they can reach up to 2,240 pounds. Meanwhile, manatees typically measure 11 feet but can reach up to 15.1 feet long. Normally weighing around 880 to 1,210, particularly massive manatees can reach up to 3,913 pounds. Among both manatees and dugongs, females tend to weigh more than males.
Dugongs and Manatees: Habitat
Dugongs and manatees may both belong to the order Sirenia, but they live on opposite ends of the planet. Dugongs are the only remaining representatives of the Dugongidae family, and their current range is much more limited than in the past. Today, they live in the Indo-West Pacific, from the coasts of East Africa to the waters of Northern Australia. Throughout their range, they live in shallow, saltwater areas near coasts including bays, harbors, and mangrove channels.
On the other hand, manatees belong to the family Trichechidae and are broken up into three different species. These include the Amazonian manatee found in the Amazon Basin, the West Indian manatee native to the Caribbean and Gulf of Mexico, and the West African manatee. Unlike dugongs, manatees spend time in both saltwater and freshwater rivers and marshy coastal areas. For example, West Indian manatees cannot live in waters below 60 degrees Fahrenheit, and so will migrate to warmer, freshwater habitats during the winter.
Dugongs and Manatees: Snout
The shape and size of the snout also rank among the most noticeable differences between a dugong vs manatee. Dugongs sport a wide, trunk-like snout similar to an elephant’s. The trunk points downwards and ends in a thin, mouth. This adaptation helps dugongs to graze on seagrasses that grow on the bottom of the seabed. Meanwhile, the snouts of manatees appear visibly shorter than those of dugongs. In addition, manatees developed a divided, prehensile upper lip which helps them to gather food and communicate with their fellow manatees.
Dugongs and Manatees: Teeth
Although dugongs and manatees are both herbivores, they evolved very different sets of teeth. Dugongs grow two incisors, or tusks, which emerge when males hit puberty. Females also grow tusks, but theirs typically don’t emerge until much later in life. Based on the layers of growth in a tusk, scientists can estimate the age of a specific dugong. Unlike dugongs, manatees do not grow tusks. Instead, they only gross cheek teeth, and there exists no clear distinction between molars and premolars. Over the course of its life, a manatee will repeatedly replace its teeth, with new teeth growing at the back of the mouth and old teeth getting pushed out the front. This phenomenon is called “marching molars,” and is similar to how an elephant’s teeth grow.
Dugongs and Manatees: Tail
Another obvious feature that separates a dugong vs manatee concerns the shape of their tails. Dugongs evolved a fluked, dolphin-like tail, which contains deep notches and a trailing edge. They move forward by flapping their tail up and down, and can also twist it to help them change direction. Evidence suggests that dugongs will occasionally stand on their tail while breaching their heads above the surface of the water to breathe. On the other hand, manatee tails look paddle-shaped, and more similar to the tail of a beaver. Like a dugong, a manatee generates movement by flapping its tail up and down.
Dugongs and Manatees: Skin
There are several slight differences in the skin of a dugong vs manatee. Dugongs have thick, smooth skin that typically looks light gray or cream at birth. As they mature, their color can grow darker and may appear brown or dark gray. This may be due to the fact that their backs and tails slowly accumulate a layer of algae growth over time. While manatees also tend to develop a growth of algae and undergo a color change, the texture of a manatee differs from that of a dugong. A manatee’s skin is much rougher and more wrinkled than a dugong’s but just as thick. Like a dugong, a manatee’s skin is covered in coarse, short hair, which helps it to feel its way around in its environment.
Dugongs and Manatees: Nails
Both dugongs and manatees possess flippers that they use to help them swim and navigate through the water. However, there is a small difference in their flippers that can help you spot the difference between a dugong vs manatee. Unlike manatees, the flippers of a dugong lack nails. West Indian and African manatees grow three or four tiny nails at the end of their flippers, which appear similar to the toenails of an elephant. Scientists believe that their toes are holdovers from when manatees used to walk on land. Now, the nails may help manatees to hold on to the seafloor and pull out plants.
Dugongs and Manatees: Diet and Feeding
While both herbivores, the diet and feeding behavior of a dugong vs manatee differ in a few key ways. Dugongs primarily subsist on seagrass, but may occasionally eat invertebrates including squids and octopuses. When feeding, they will eat the entire plant, including the roots, although they appear to prefer to eat just the leaves. In addition, they tend to feed on areas where seagrass is less abundant rather than more heavily overgrown areas. This may be done to maximize the intake of high-nutrient seagrasses rather than eating massive amounts of low-nutrient vegetation.
While manatees also eat seagrasses, they also eat a wide variety of freshwater grasses. In addition, evidence suggests that manatees will occasionally eat small fish, which they tend to take from nets. When feedings, manatees “walk” on their flippers, which they also use to dig up plants and roots. They will then use their flippers to push food towards their mouths and grab the food with their lips.
Dugongs and Manatees: Mating and Reproduction
Another difference between a dugong vs manatee concerns their mating and reproduction habits. Dugongs tend to be monogamous and mate for life, although they may take another partner if their current partner passes away. Female dugongs typically reach sexual maturity between 6 and 17 years old, with an average age of around 10 years. Meanwhile, manatees typically follow a polygamous lifestyle, with some males having several sexual partners at a time. In addition, female manatees reach sexual maturity at a younger age and may bear their first calf around 3 years old.
Frequently Asked Questions Concerning Dugongs and Manatees
How old do dugongs and manatees live?
Both dugongs and manatees are relatively long-lived. While they reach sexual maturity at a young age, they can live up to 65 or 70 years old.
How long can dugongs and manatees hold their breath?
Although they can hold their breath for up to 20 minutes, dugongs and manatees typically surface every few minutes to breathe.
Do dugongs and manatees sleep underwater?
Dugongs and manatees sleep near the surface. They flip on their backs and float near the surface of the water so they can sleep and breathe simultaneously.
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