| African manatee | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Sirenia |
| Family: | Trichechidae |
| Genus: | Trichechus |
| Species: | T. senegalensis |
| Binomial name | |
| Trichechus senegalensis Link, 1795 |
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| African manatee range | |
The African manatee (Trichechus senegalensis), also known as the West African manatee or seacow, is a species of manatee and eats mostly plants. African manatees can be found in much of the western region of Africa, from Senegal to Angola.[2]
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The African manatee was officially declared a species under the Trichechus senegalensis taxon in 1795 by the naturalist, Johann Heinrich Friedrich Link. There aren't any known subspecies of this taxon, but unreliable claims have been made that there are morphological disparities between coastal manatee populations and populations that have been isolated inland. After more research, it was proven that there is no genetic evidence to support these claims and form any subspecies.[1] The African manatee falls under the Trichechus genus with only two other species, the Amazonian manatee and the West Indian manatee, which are also sirenians.[3]
African manatees can be found in much of the western region of Africa, such as in the countries of Angola, Benin, Cameroon, Chad, Republic of the Congo, Democratic Republic of the Congo, Côte d'Ivoire, Equatorial Guinea, Gabon, The Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone and Togo. Not only are these manatees found in many countries, but also in many different kinds of bodies of water, ranging from brackish to freshwater. They can be found in oceans, rivers, lakes, coastal estuaries, reservoirs, lagoons, and calm shallow bays on the coast.[1]
First, some are located along the west coast of Africa in the southeastern and central eastern waters of the Atlantic Ocean. Manatees are found as far offshore as 75 km (47 mi) out, where there are shallow coastal flats and calm mangrove creeks filled with seagrass. Lakes where they dwell include Lake Volta, Inner Niger River Delta in Mali, Lake Léré, and Lake de Tréné. Due to fluctuating flow rates and water levels in rivers, some of these permanent lakes serve as a refuge during the dry season to manatees in connecting rivers. From north to south, the river systems that they can be sited in include the Senegal, Saloum, Gambia, Casamance, Cacheu, Mansôa, Geba, Buba, Tombali, Cacine, Kogon, Kondoure, Sierra Leone, Great Scarcies, Little Scarcies, Sherbro, Malem, Waanje, Sewa, Missunado, Cavalla, St. Paul, Morro, St. John, Bandama, Niouniourou, Sassandra, Comoé, Bia, Tano, Volta, Mono, Oueme, Niger, Mekrou, Benue, Cross, Katsena Ala, Bani, Akwayafe, Rio del Rey, Ngosso, Andokat, Mene, Munaya, Wouri, Sanaga, Faro, Chari, Bamaingui, Bahr-Kieta, Logoné, Mitémélé, Gabon, Ogoué, Lovanzi, Kouilou, Congo, Dande, Bengo, and Cuanza. They go up these rivers until they are unable to progress due to water that is too shallow for them to swim through or strong waterfalls that they cannot pass.[1]
One way that African manatees are like West Indian manatees is that they both need habitats that have protected water with access to food and freshwater. They occasionally journey to less sheltered areas, but this is a rare occurrence. Out of all of their many habitats in Africa, the most populated areas seem to be Guinea-Bissau; the lagoons of Ivory Coast; the southern portions of the Niger River in Nigeria; Sanaga River, Cameroon; coastal lagoons in Gabon; and the lower parts of the Congo River. A study was done in Côte d'Ivoire to find where most African manatees favored living. They were radio-tagged and tracked, and the results were that they were sighted the most in coastal lagoons with plenty of their main food source, mangroves and other herbaceous growths; in grass-lined estuaries of big rivers with plenty of mangroves; and protected coastal spots with less than 3 meters of water, again, with bountiful mangroves and also marine macrophytes.[1]
Although generally speaking, manatees are herbivores, the African manatee also eats clams. The majority of the diet of the African manatee is composed of many different types of flora found underwater, on the shoreline, and floating in the water. Each day, the African manatee will eat approximately 4% to 9% of its body weight in wet vegetation.[2]
The shape of an African manatee's body is such that it is "full around the middle and narrowing to a paddle-shaped tail". On average, the length of an adult African manatee measures about 3 meters (10 feet), but it has been known for larger African manatees to grow to a length of 4 meters (13 feet). The African manatee is gray in color. However, algae and other tiny organisms often grow on them so that the manatees appear brown or green-ish.[2] The weight of an adult African manatee is up to approximately 907 kilograms (2,000 pounds). African manatees are extremely slow, moving at between 4.8 and 8 kilometers (only 3-5 miles) an hour, unless they fear predators, at which time the manatee can travel at speeds of approximately 32 kilometers (20 miles) an hour. The African manatee's forelimbs, or flippers, are used to bring food to the manatee's mouth, after which the vegetation is chewed by the manatee's strong molars. If these molars happen to fall out, new molars grow in their place. The manatee's flippers are also used "to embrace and touch other manatees".[4]
One cannot tell the sex of an individual African manatee without closely examining the manatee's underside. The only visible distinctions between males and females are the genital openings. However, males tend to be smaller than females. Some female African manatees are sexually mature after as little as 3 years of age. Male African manatees take a much longer time to mature, about 9 to 10 years. Rarely will a male African manatee be able to fertilize an egg at 2 or 3 years of age. When male and female African manatees mate, it is not for life. Multiple males will usually mate with one female.[2]
The African manatee has become a vulnerable species because its meat, oil, bones (used to make walking stick handles and "spinning-tops used in a local game called cii"), and skin bring great wealth to poachers. Although the species is protected in the countries in which it lives, these laws are poorly enforced. In some countries, such as Nigeria and Camaroon, African manatees are sold to zoos, aquariums, and online as pets, sometimes being shipped internationally. Anyone visiting such countries would easily notice the manatee meat being sold on the streets and marketplaces, but the lack of law enforcement prevents the poachers from being punished. Residents of countries such as Mali and Chad depend on the oil of the African manatee to cure ailments such as ear infections, rheumatism, and skin conditions.[1]
Urban and agricultural development, increased damming, and increased use of hydroelectric power in rivers in countries such as Côte d’Ivoire and Ghana are more threats to the African manatee's habitat and life, and thick congestion of boats in waterways may cause African manatees to have a deadly run-in with the vessels. However, even natural occurrences such as droughts and tidal changes often strand manatees in an unsuitable habitat, and some African manatees are killed accidentally by fishing trawls and nets intended for catching sharks.[1]
Some behaviors of African manatees provoke humans' desires to hunt them. When the African manatees get tangled up in fishing nets, the animals can do damage to the nets. People in countries such as Sierra Leone feel that if they kill and therefore reduce the number of African manatees, the chances of their nets requiring expensive repairs will be lessened. In addition, African manatees have been known to destroy rice crops by drifting into fields during the rainy season, which is another reason for humans to want to kill them.[5]
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