feed on a variety of aquatic macrophytes, including aroids (especially Pistia, aka "water lettuce"), grasses, bladderworts, hornworts, water lilies, and particularly, water hyacinths. They are also known to eat palm fruits that fall into the water. Maintaining a herbivorous diet, the manatee has a similar post-gastric digestive process to that of the horse. The manatee consumes approximately 8% of its body weight in food per day. During the July–August dry season when water levels begin to fall, some populations become restricted to the deep parts of large lakes, where they often remain until the end of the dry season in March. They are thought to fast during this period, their large fat reserves and low metabolic rates – only 36% of the usual placental mammal metabolic rate – allowing them to survive for up to seven months with little or no food. Reproduction and lifecycle The Amazonian manatee is a seasonal breeder with a gestational period of 12–14 months and a prolonged calving period. Most births take place between December and July, with about 63% between February and May, during a time of rising river levels in their native region. After the calf is born, it will begin to eat while staying with its mother for 12 – 18 months. Two individuals lived 12.5 years in captivity. Wild individuals have a lifespan of about 30 years. Population and distribution As of 1977 the population count of the Amazonian manatee was estimated to be around 10,000. As of now the total population count is undetermined, however the population trend seems to be decreasing. They are mainly distributed throughout the Amazon River Basin in northern South America, ranging from the Marajó Islands in Brazil through Colombia, Peru, and Ecuador. They are occasionally found overlapping with the West Indian manatee along the coasts of Brazil. Amazonian manatees occur through most of the Amazon River drainage, from the headwaters, in Colombia, Ecuador and Peru to the mouth of the Amazon (close to the Marajó Island) in Brazil over an estimated seven million square kilometers. However, their distribution is patchy, concentrating in areas of nutrient-rich flooded forest, which covers around 300,000 km2 They also inhabit environments in lowland tropical areas below 300 m asl, where there is large production of aquatic and semi-aquatic plants; they are also found in calm, shallow waters, away from human settlements The Amazonian manatee is completely aquatic and never leaves