Although manatees and elephants have a similar ancestor known as Tethytheria, manatees did not develop from elephants but did descend from the same set of ancestors as elephants. These early hoofed mammals existed during the early Cenozoic age and were little animals that resembled rodents and lived on land. They lived throughout this time period. Over the course of time, some of these animals eventually developed into the land-dwelling elephants that we are familiar with today, while others eventually evolved into the marine-dwelling manatees that we know today.
The appearance of manatees can be compared to that of elephants in several ways. Both of these creatures have skin that is rough and wrinkled, and their bodies are covered with hair that is sparse and bristly. The hairs on the manatee’s head are called vibrissae, and they are used to detect vibrations in the water surrounding them.
The appearance of hyraxes is similar to that of marmots and other rodents, but in reality, they are more closely related to manatees and elephants. Hyraxes, like manatees, have vibrissae scattered throughout their fuzzy coats.
Evolutionary Relationships
The first manatees did not appear until approximately 15 million years ago, during the Miocene Epoch, although they were descended from the ancient Sirenians. According to “Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals,” the emergence of the first elephants from the Proboscideans occurred during the same period. Although neither of these two mammalian species is a direct descendant of the other, they share similar DNA due to their evolutionary relationship. Even if they are not in the same family, genus, or species, a large number of ostensibly unrelated species share a genetic relationship.
According to the Annenberg Lerner website, modern species of manatees, elephants, hyraxes, and aardvarks are all closely related and classified as “subungulates.” Subungulates are all descended from primitive ungulates, but not directly from one another.
The Evolution of the Manatee and Elephant
Sirenians, the progenitors of manatees, first appeared approximately 55 million years ago during the Eocene Epoch of the Cenozoic Era. According to the website of the University of Edinburgh’s Natural History Collections, these marine organisms once inhabited the Tethys Sea, located between Africa and Eurasia.
Simultaneously with the emergence of the Sirenians, the land-dwelling Proboscideans evolved from the Tethytheria. Manatees are members of the Sirenia order and direct descendants of the Sirenians. On the other hand, elephants are direct descendants of the Proboscideans, making these two families closely related but not directly related.
Manatees in Today’s World
The West Indian, the West African, and the Amazonian manatees are the only three species of manatees that still exist today. According to the Dolphin Research Center, there are two sub-species that fall under the West Indian species. These sub-species are found in Florida and the Caribbean. These gentle giants have thick skin that is covered with bristles, claws on their forelimbs, and replacement teeth; manatees even have a trunk-like flexible top lip. Manatees are related to land-dwelling elephants and share many of their physical characteristics.
According to the Save the Manatee Club, these enormous animals, which weigh anywhere from 800 to 1,200 pounds on average, are in risk of extinction because their habitat is being destroyed, they are being hunted, and they are colliding with boats.
Marine Mammals
Even though they seem quite similar to one another, manatees are not related to any of the other marine animals in any way, even via evolution. The majority of marine mammals, including dolphins, whales, and porpoises, are classified under the order Cetacea and are descended from a group of species that were also classified under the name Cetacea. This indicates that the manatee’s closest relatives are not other marine mammals but rather animals that live on land, such as elephants and hyraxes, rather than other marine mammals.
According to Sirenian International, the manatee is the only species of marine mammal that is classified as a herbivore. Like elephants and hyraxes, manatees are herbivores.
Where do manatees live?
The West Indian manatee (Trichechus manatus), the African manatee (Trichechus senegalensis), and the Amazonian manatee (Trichechus inunguis) are all different kinds of manatees.
The average size of a West Indian manatee is about 3.5 meters long and 500 kilos. It goes between freshwater and saltwater, using mangroves and coral reefs along the coast, as well as rivers, lakes, and ponds in the middle of the country.
The West Indian manatee comes in two different kinds. The Antillean or Caribbean manatee (Trichechus manatus manatus) lives in waters from the Bahamas to Brazil. The Florida manatee (Trichechus manatus latirostris), on the other hand, lives in US waters, although some individuals have been seen in the Bahamas.
During the winter, the Florida manatee stays mostly in Florida. When the temperature of the water around it drops below 20°C, it goes to warmer water, both natural and man-made, like the warm-water outfalls from power plants.
During the warmer months, manatees in Florida frequently move to neighboring states such as Georgia, although some travel much farther than that. In 1995, a manatee made the journey all the way from southeast Florida to Rhode Island and back again. This manatee, affectionately known as Chessie, broke the record for the longest round journey by traveling more than 4,000 kilometers.
Also about 3.5 meters long, the African manatee lives along the west coast of Africa, from Mauritania to Angola. African manatees also use rivers. These animals can be found in Mali and Niger, which don’t have any oceans.
The smallest species is the Amazonian manatee, which is still a big animal. It gets to be about 3.5 feet long and 2.5 meters long. Manatees in the Amazon like quiet, shallow water that is warmer than 23°C. This species only lives in waters in the Amazon Basin, which includes Brazil, Colombia, Ecuador, and Peru.
Some interesting facts about manatees
Unlike humans, whose brains have cortical folds, manatees’ brains are smooth, and their brains are the smallest in relation to their bodies of all mammals. Even though they aren’t as smart as dolphins, manatees can learn simple jobs, are very sensitive to touch, and can tell colors apart.
Most female manatees have one calf every two to five years, and the baby stays with the mother for two years to nurse. The teats of the mother cow are right where the front legs meet the body. This is where the calf feeds. Even when they are only a few weeks old, the babies can start chewing on plants.
Most mammals, like humans, giraffes, whales, and rats, have seven vertebrae in their necks. Only tree sloths and manatees have an odd amount of vertebrae, with the manatee having only six. Scientists think this might be because their metabolisms are slow.
In the wild, manatees don’t have any natural enemies, but people have done a lot to put all three species at risk of dying out. About half of the deaths of West Indian manatees are caused by people. Most of these deaths are caused by boats hitting them. Manatees are very buoyant, and they control their buoyancy with their horizontally placed stomach and the way they breathe. Manatees are too slow to get out of the way of a fast boat because they move between 3 and 5 miles per hour on average.
Humans have one set of infant teeth, and if we loose or damage an adult tooth, we must visit the dentist. Manatees, like their elephant relatives, continually replace their teeth throughout their lifetimes, with the front teeth falling out and the rear teeth growing in.
Every three to five minutes, manatees come to the top of the water to breathe. However, they can stay beneath longer and hold their breath for up to 20 minutes. When they do take a breath, they replace 90% of the air in their lungs. Humans, on the other hand, usually only replace 10%.
Are manatees endangered?
Manatees are either endangered or face a very high risk of extinction.
The International Union for the Conservation of Nature (IUCN) lists both the African manatee and the Amazonian manatee as Vulnerable.
Between 1935 and 1954, an estimated 140,000 Amazonian manatees were slaughtered for their flesh, fat, and skin, the latter of which was used to create leather. The decline of the African manatee has been linked to accidental capture in fishing nets and poaching. Manatee poaching is now prohibited in all African nations where the animal is located.
The West Indian manatee is also listed as Vulnerable because its population is thought to number fewer than 10,000 individuals. The Florida and Antillean manatees are listed as Endangered by the IUCN because there are fewer than 2,500 individuals of each subspecies. Both are anticipated to decline by 20% over the next four decades.
How fast is a manatee able to swim?
The metabolism of manatees is far slower than that of other animals of comparable size. Although they are normally sluggish swimmers, they are capable of reaching speeds of up to roughly 25 kilometers per hour for brief periods of time. However, this is not their regular swimming style.
