West African manatee

The African manatee (Trichechus senegalensis), also known as the West African manatee, is a species of manatee that is mostly herbivorous. African manatees inhabit much of the western region of Africa – from Senegal to Angola. Although not a great deal is known about this species, it is hypothesized that the African manatee is very similar to the West Indian manatee (Trichechus manatus). The African manatee was officially declared a species under the Trichechus senegalensis taxon in 1795 by naturalist Johann Heinrich Friedrich Link. No subspecies of this taxon are known. Although African manatees live in both coastal areas and isolated inland areas, genetic evidence suggests no significant differences between the two populations. The African manatee falls under the genus Trichechus with only two other species, the Amazonian manatee and the West Indian manatee, which are also sirenians. African manatees can be found in West African regions: Angola, Benin, Cameroon, Chad, the Republic of the Congo, the 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. Manatees are found in brackish waters to freshwater: in oceans, rivers, lakes, coastal estuaries, reservoirs, lagoons, and bays on the coast. African manatees rarely inhabit waters with a temperature below 18°C (64°F). Manatees have been found as far as 75 kilometres (47 mi) offshore, where there are shallow coastal flats and calm mangrove creeks filled with seagrass. Inland lakes where manatees dwell include Lake Volta, the 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 refuges for manatees in connecting rivers during the dry season. From north to south, the river systems that contain manatees 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. Manatees move up these rivers until they are unable to proceed because of shallow waters or strong waterfalls. The areas with the highest manatee populations are Guinea-Bissau, the lagoons of Côte d'Ivoire, the southern portions of the Niger River in Nigeria, the Sanaga River in Cameroon, the coastal lagoons in Gabon, and the lower parts of the Congo River. As part of a study completed in Côte d'Ivoire to assess where the majority of African manatees favor living, a sample of African manatees was radio-tagged and tracked. The tracking observed most of the sample in coastal lagoons, mangroves, and other herbaceous growths. They were also found in the grassy estuaries of big rivers with mangroves and in protected coastal spots with less than 3 metres (10 ft) of water containing both mangroves and marine macrophytes. Manatees are herbivores; however, they also eat clams, mollusks, and fish found in nets. The percentage of the diet that is composed of non-plant material varies based on location . With manatees living off the coast having a lifetime average of 50% non-plant material . The West African manatee is the only Sirenian that seems to intentionally consume non-plant material. A majority of the African manatee's diet is made up of a variety of flora found above or hanging over the water. African manatees that inhabit rivers mostly eat the overhanging plants growing on the river banks. The diet of African manatees living in estuaries consists solely of mangrove trees. Each day, the African manatee eats about four to nine percent of its body weight in wet vegetation. Microorganisms within the African manatee's large intestine, which measures up to 20 metres or 66 feet in length, aid it in digesting the large quantity and variety of vegetation that it consumes daily. The African manatee's body is widest at the middle, and its tail resembles a paddle. The manatee is gray in color with small, colorless hairs that cover its body. However, algae and other tiny organisms often grow on an African manatee's body, so its body sometimes appears brown or greenish in color. Calves are darker in color when they are very young. African manatees measure up to 4.5 m (15 ft) in length, and weigh about 360 kilograms (790 pounds). African manatees are typically extremely slow, moving between 4.8 km and 8.0 km (3 and 5 mi) per hour, although when scared by predators they can travel at speeds of about 32 km (20 mi) per hour. The African manatee's large forelimbs, or flippers, are used to paddle and to bring food to its mouth. Vegetation is then chewed by the manatee's strong molars, which are its only teeth. When the manatee is born, each jaw has two vestigial incisors, which the manatee loses as it matures. If the African manatee's molars happen to fall out, new molars grow in their place. The manatee's flippers, which have nails, are also used to graze other manatees. The African manatee does not have any hind limbs. From the exterior, the African manatee looks very similar to the American manatee; however, the African manatee is different from the Amazonian manatee, which has characteristic white markings on its abdomen. The West African manatee is a descendant of trichechids found in coastal South America during the Pliocene Epoch. Although they tend to stay in freshwater, theory suggests that, through transoceanic currents, the species reached West Africa during the late Pliocene. The West African manatee's appearance is thought to be the result of these currents and species movement. The African manatee's ancestors passed down advantageous migration and food traits. The African manatee is not restricted to a certain area, and does not have to rely heavily on only one ecosystem for support. This evolution of the African manatee's diversity may be part of its key attribute to survival. They are more diverse than other manatees due to their ability to survive in salt water, although they do need access to fresh water for drinking purposes.