Now That's Old!
The South Florida Museum's Parker Manatee Aquarium houses the oldest living captive manatee, Snooty, who was born on July 21, 1948, which makes him well over 60 years old!
Also known as sea cows, manatees are sea mammals that are quite big in size, but gentle in nature. There are three living species of manatees, each exhibiting varied characteristics. As per scientific evidences, they are believed to have been evolved from quadruped (four-legged), terrestrial, plant-eating mammals, about 60 million years ago. The closest surviving relatives of manatees are those belonging to the order Proboscidea (e.g. elephants) and Hyracoidea (e.g. hyrax).
|Species||Trichechus manatus (West Indian manatee)
Trichechus inunguis (Amazonian manatee)
Trichechus senegalensis (African manatee)
Manatees are either gray or grayish-brown in color. They have a thick, wrinkled skin, on which algal growth is commonly observed. The skin on the head and face is comparatively more wrinkled than the other body parts. They have two small eyes and whiskers in the snout portion. They use their large, flexible upper lip as a short trunk for gathering and eating food, as well as for communicating among themselves.
Though it is a fact that manatees do not have external ears, their auditory system is sharp, and they can hear sounds of varied frequencies. The two forelimbs, also called flippers, help them to swim and glide through the water currents. At times, they use their flippers while crawling in shallow waters. Their flippers are not strong enough to support them on land.
Their enormous body tapers into a flat, paddle-shaped tail that also helps in propelling through the water. Their average body length may range from 2.8-3.0 m, whereas the average weight is about 400-550 kg (900 to 1200 pounds). The females are larger and heavier than the males. They are very slow, and move at a speed of about 3-5 miles per hour. As they are not adapted to breathe underwater, they come to the water's surface every few minutes for air.
Manatees prefer shallow waters either in the rivers, estuaries, canals, or coastal areas. They cannot survive in cold waters, which is why they are found in the Amazon Basin, Florida, West Africa, Gulf of Mexico, and the Caribbean Sea. The water temperature must be above 60°F (16°C). When the temperature drops in winter months or due to any other reason, they move to warmer locations. This is because, although they are huge, these mammals have very less fat in their bodies. Thus, they feel cold quite easily and cannot survive in cold waters.
Manatees are herbivorous animals that feed on a wide variety of algae and plants. According to studies, it is found that they can feed on as many as 60 plant species. In general, an adult consumes about 10 percent of its body weight daily, which accounts to about 50 kg. They use their front flippers to dig through the floor of the river, and also use these to scoop the vegetation and roots, that they find, into their mouths. Captive manatees are fed leafy greens like lettuce. Their predators are rare and include humans, crocodiles, alligators, and sharks.
Manatees are solitary animals, except during mating. Females attain sexual maturity at the age of five years, whereas males are active by the age of nine years. They breed only once a year, but the timing is not specific. The female can mate at any time of the year, and she has multiple partners. The males compete with each other to be the first to mate.
The gestation period of manatees is 11 to 13 months, after which a single calf is born. The calf is born underwater, and is then pushed up to the surface by its mother for breathing. At birth, a calf weighs about 30 kg (70 pounds) and is 4 to 5 feet long. The female nurses it for anything between 14 to 24 months. It starts munching on plants a few weeks after birth. It is believed that manatees reproduce every 2 to 4 years, and twins being born is a very uncommon event.
Intelligence and Communication
The brain of a manatee has a smooth surface, unlike the human brain, which has many folds. However, these animals are considered to be quite intelligent. They have a very good long-term memory, which makes them quite easy to train. They are also able to differentiate between colors! They are friendly animals that frequently interact with snorkelers and divers.
Manatees communicate with each other through touch, sound, smell, taste, hearing, and sight. They express fear, anger, play with each other, and the most evident communication is observed between the mother and the calf. Their communicating methods include chirping, whistling, and squeaking, and they can detect sounds over a great distance as well as pick up on vibrations in the water.
Population and Culture
As per statistics, the maximum population of manatees is found in Florida (approximately 3,000), and hence, they are the state marine mammal of Florida. Their overall population is, however, very low (lesser than 10,000). These animals are not commonly kept captive. They are normally kept as a part of rescue and rehabilitation, or in case of an abandoned or orphaned calf. They are usually released into the wild, unless it is a surety that they will not make it without human assistance. Although they adapt quite easily, they are better off in the wild. Also, the cost of their upkeep is pretty high.
Various researches have been conducted on Florida manatees. They have also been mentioned in the folklore of many cultures. For example, the western Africans regard manatees to be sacred mammals, as they have a belief that these animals evolved from humans. Hence, killing them is banned according to their culture. Some indigenous people use their bones for the treatment of ailments like asthma and earache.
Threats and Conservation status
As per the IUCN Red data list, all three species of manatees are declared as endangered, which means vulnerable to extinction. A major threat to their population is their declining habitat. Since they are slow swimmers, they are prone to injury by fast-moving boats and/or propellers. Many times, the injury causes infections that may prove fatal. Hence, manatee-inhabited areas require boats to slow down so as not to hurt any animal that gets in their way. Being curious by nature, they are known to swim up and check out boats.
Previously, they were hunted for their meat and valuable bones, as well as for making war shields, shoes, and other boat equipment. Nowadays, hunting and poaching manatees is banned under certain wildlife conservation acts. For example, the Endangered Species Act, 1973, makes it illegal to hunt, hurt, trap, or even harass a manatee.
- The length of the intestine of manatees is more than 150 feet!
- Their teeth are constantly replaced, like elephants.
- They are extremely sensitive to touch.
- Manatees have just 6 vertebra as opposed to 7 in most mammals. Thus, they cannot turn their head sideways!
- Despite their small eyes, manatees have excellent vision.
- Their lifespan is about 60 years.
- Manatees can hold their breath underwater for about 15 minutes!
- A male manatee is called a bull, whereas a female is called a cow. A baby is called a calf.
Manatees are fascinating creatures that have a calm disposition and very cute looks. That coupled with their docile and friendly nature makes them all the more endearing. More efforts need to be taken to save these animals from extinction, as losing them forever will be a great loss indeed.