Today, we dive into fresh and saltwater to discover more about manatees! We will also look at the differences between manatees and dugongs! They both belong to the order Sirena and have incredible characteristics that make them lovable, important to their ecosystems, and worth learning about.
A Whole Lot of Manatee Love
There are three different species of manatee: the West Indian manatee, the Amazonian manatee, and the African manatee. The manatees’ closest relative is the elephant! They are also very closely related to the rock hyrax. Manatees may appear “fat,” and they are large mammals, however, there’s an important distinction to be made! Manatees don’t have blubber as cold-water marine mammals do. They have alternating layers of fat and muscle that give them a larger appearance. Generally, they can weigh anywhere from 440 to 1,300 pounds.
With large bodies and an aquatic home, they must regulate their buoyancy. Depending on their activity and speed, they can hold their breath for about 15 minutes but must come to the surface of the water to breathe. Their rib cage and muscles are super important for this! They will reduce the volume of air in their lungs and create a more dense center of gravity. Their lungs are located along their spine and run throughout two-thirds of their body. The compression and expansion of their dense lungs allow them to swim up and down to achieve balance. Additionally, they can use flatulence for buoyancy. Flatulence is the act of passing gas from one’s digestive system. Manatees are very resourceful!
Photo Source: Alison Mott, previous volunteer for Wildtracks
Living Their Best Manatee Life
Due to their lack of blubber, they are extremely sensitive to colder water temperatures. To survive, they will never live in water that is colder than 68 degrees Fahrenheit. They are found in warmer waters, such as the temperate waters in Florida to Brazil, the Amazon River, and coastal regions of Africa (National Geographic). The typical habitats for manatees are mangroves, rivers, lakes, estuaries, coastal regions, and hot springs.
As an herbivorous grazer, they can spend 6-8 hours a day eating...this is the dream! They feed on a variety of aquatic flora including grasses, weeds, algae, and leaves. In a single day, they can eat 100-200 pounds of vegetation! Their teeth are essential to their grazing (and graceful) lifestyle. Manatees have “hind molar progression.” This means that their molars towards the back of the mouth are always growing! As they eat and wear down the front teeth, they will fall out. When they fall out, the molars are fully exposed-which positions new teeth towards the front of the mouth (Padi Dive Blog).
Nicknamed “sea cows,” they are slow-moving yet talented swimmers. They can move or glide at speeds of 5 mph up to 20 mph (in short bursts). Dugongs move at a similar speed, but have a much different tail!
Tail Me About It!
There are a few differences between dugongs and manatees. However, Alison Mott says, “The easiest way to know a manatee from a dugong is their tail. Manatees have paddle-like tails, dugongs have a dolphin-like tail.” In the photo shown above, it is easy to see the horizontal, single-lobed tail of the manatee compared to the fluke style tail, double-lobed, of the dugong (pictured to the left). Their tails are similar in size, but function in a much different way to achieve mobility. Fun fact: dugongs have been seen standing on their flukes with their heads poking out of the water.
Additionally, location is crucial! Dugongs are only found in Australia, New Zealand, and South Asia whereas manatees are found in Florida, the Amazon, and Africa. Within their locations, they have different needs for water composition. Dugongs primarily live in saltwater, but manatees can live in both saltwater and freshwater.
When it comes to longevity and lifespan, dugongs take the cake! They can live up to 70+ years, whereas manatees generally live 35-50 years.
Dugongs are monogamists and manatees are polygamists. Polygamy is where males can have multiple females as mates. Manatees are considered “semi-social.” They can be seen alone, just mother and calf, or a small group of about 6 individuals. A group of manatees is called an aggregation. On the contrary, dugongs are very social. Their group sizes can grow up to 100-200 individuals. Unfortunately, due to habitat destruction and loss, their group sizes can be diminished due to a lack of space in the seagrass beds. They will travel to find seagrass beds with adequate resources for their group. Both animals have been seen communicating, playing, interacting, and helping members of their group!
Photo Source: National Geographic
Have Some Hu-Manatee
Manatees were previously considered endangered but their numbers have increased and they have been reclassified. Both manatees and dugongs are now considered threatened and still have declining populations due to human activity. They are both hunted for their fat and oil. In fact, another (previous) member of the Sirena, the Stellar’s sea cow, was hunted to extinction in 1768. Manatees and dugongs are often hit or struck by fast-moving boats and killed or injured. Additionally, manatees can become trapped canals by boat activity or even become caught up in fishing nets. When they are trapped in canals or stuck in less desirable waters, they can quite literally and tragically freeze to death if the water is too cold. It is so important to respect their space and allow them to thrive in their habitat.
Protecting important habitats, such as mangroves, is a great way to aid in their conservation. Additionally, spreading awareness will help these animals. Government and agency protection for these marine mammals is essential for their survival. Thanks for reading and have a great holiday season!
Written By: Bailey Higa
Alison Mott, Registered Veterinary Technician & previous Wild Tracks volunteer