[2] It has thin, wrinkled brownish or gray colored skin, with fine hairs scattered over its body and a white chest patch.

[9] Amazonian manatees are large, cylindrically shaped mammals, with forelimbs modified into flippers, no free hind-limbs, and the rear of the body in the form of a flat, rounded, horizontal paddle.

[10] The flexible flippers are used for aiding motion over the bottom, scratching, touching, and even embracing other manatees, and moving food into and cleaning the mouth.

[10] The general coloration is grey, and most Amazonian manatees have a distinct white or bright pink patch on the breast.

As the teeth migrate rostrally in the manatee, the roots will be resorbed and the thin enamel will wear down until the tooth is eventually shed.

[4] Additionally, Amazonian manatees have a very small degree of rostral deflection (30.4°), which can be used as an indication of where in the water column the animal feeds.

A small degree of deflection means that the end of the snout is straighter with regard to the caudal portion of the jaw.

A small degree of rostral deflection allows Amazonian manatees to feed more effectively at the surface of the water, where much of their food is found.

[8] The species relies on changes in the peripheral circulation for its primary mechanism for thermoregulation by using sphincters to deflect blood flow from areas of the body in close contact with water.

[7] The Amazonian manatee has the smallest degree of rostral deflection (25° to 41°) among sirenians, an adaptation to feed closer to the water surface.

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.

[7] 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.

[2] However, their distribution is patchy, concentrating in areas of nutrient-rich flooded forest, which covers around 300,000 km2 [2] 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[2] The Amazonian manatee is completely aquatic and never leaves the water.

[26] The Amazonian manatee favors backwater lakes, oxbows, and lagoons with deep connections to large rivers and abundant aquatic vegetation[26] They are mainly solitary but sometimes they will gather in small groups consisting of up to eight individuals.

Traditional harpoons are the most common weapon used against the manatees, but in Ecuador they are also known to be caught in Arapaima fish traps.

Population declines are primarily a result of hunting, as well as calf mortality, climate change, and habitat loss.

[7] Manatees are also at risk from pollution, accidental drowning in commercial fishing nets, and the degradation of vegetation by soil erosion resulting from deforestation.

[7] Additionally, the indiscriminate release of mercury in mining activities threatens the entire aquatic ecosystem of the Amazon Basin.