Amazonian Manatee

Amazonian Manatee

Peixe-boi (Brazil), Sea cow, South American manatee, Amazon manatee

Trichechus inunguis
Population size
Life Span
12.5-30 years
Top speed
km/h mph 
kg lbs 
m ft 

The Amazonian manatee (Trichechus inunguis) is a large aquatic mammal with a bizarre appearance, first described as "a curious combination of a seal and a hippopotamus". It is the smallest of the three extant species of manatee. Manatees are often known as sea cows which is a reference to their slow, peaceful, herbivorous nature, reminiscent of that of bovines.


The Amazonian manatee can be distinguished by its smoother rubbery skin and lack of vestigial nails on its flippers. Manatees have forelimbs modified into flippers, no free hind limbs, and the rear of the body in the form of a flat, rounded, horizontal paddle. 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. The manatee's upper lip is modified into a large bristly surface, which is deeply divided. It can move each side of the lips independently while feeding. The general coloration is grey, and most Amazonian manatees have a distinct white or bright pink patch on the breast. Their teeth are continuously replaced horizontally from the caudal portion of the jaw to the rostral portion throughout the manatee's life, a unique trait among mammals.




Biogeographical realms

Amazonian manatees occur throughout the Amazon Basin in northern South America (Colombia, Ecuador, Peru, and Brazil). They live in freshwater oxbows, blackwater lakes, and lagoons which have deep connections to big rivers and plenty of aquatic vegetation.

Amazonian Manatee habitat map

Climate zones

Amazonian Manatee habitat map
Amazonian Manatee
Attribution-ShareAlike License

Habits and Lifestyle

Amazonian manatees are gregarious animals and used to occur in big herds. Due to severe overhunting, however, groups seen today number only 4 to 8 individuals. These manatees are both nocturnal and diurnal and they live their lives almost entirely underwater. Only their nostrils stick up above the water as they search the bottoms of rivers and lakes for lush vegetation. An individual in one day can eat as much as eight percent of its body weight of aquatic vegetation. Manatees have nostrils, not blowholes like other aquatic mammals, which close when underwater to keep water out and open when above water to breathe. They can remain underwater for extended periods but usually surface for air about every five minutes. Manatees make seasonal movements that depend on the flood regime of the Amazon Basin. They are found in flooded forests and meadows during the flood season when food is abundant. Amazonian manatees vocalize alone and with others, particularly between cows and their calves.

Group name
Seasonal behavior

Diet and Nutrition

Amazonian manatees are herbivores (graminivores, folivores). They eat a wide vriety of aquatic plants such as "water lettuce", grasses, bladderworts, hornworts, water lilies, and particularly, water hyacinths. They are also known to eat palm fruits that fall into the water.

Mating Habits

1 year
1 calf
18 months

Mating herds form that consist of a male and a few females. The females have the freedom to leave their herd and so may mate with another male, meaning that Amazonian manatees may have a polyandrous mating system. Breeding can take place throughout the year, with peaks occurring at different times in various parts of the system of rivers. In the central Amazon, births mostly occur in February-May, which is when water levels rise. A single young is born after gestation of around one year. Births occur at 2-3 year intervals. Young are very well looked after by their mothers, who will nurse them up to the age of 18 months. Males are 5 to 6 years old when they first mate, and females much younger, with their average age being about 3 years old.


Population threats

Once occurring in large herds and with healthy population numbers, Amazonian manatee numbers have decreased due to extensive hunting by commercial and subsistence hunters. It has been hunted for meat, fat, and oil, and in the past for its hide, for use as machine belts and water hoses. Current threats include hunting and drowning accidentally in commercial fishing nets. Large areas surrounding the manatee’s river habitats being deforested has also caused the soil to erode, as well as degradation of food sources and reduction in vegetation in the waterways.

Population number

Although manatees are widespread through a large area, there is a high level of uncertainty about total population size. According to the IUCN Red List resource, a minimum of 10,000 individuals was estimated in 1977 for the Amazon Basin as a whole. Currently Amazonian manatees are classified as Vulnerable (VU) and their numbers today continue to decrease.

Fun Facts for Kids

  • Despite eating in a slow and secretive manner, an Amazonian manatee each day can eat as much as 8% of its body weight.
  • Although an Amazonian manatee has tiny eyes, surprisingly it can see very well, and it even has a membrane that it can draw across its eyeballs for protection. It also has great hearing, despite having no outer ear structure. (It does have large bones in its inner ear.)
  • An Amazonian manatee has endearing whiskers all over its snout. Evidence suggests that a manatee has a 6th sense, enabling it to detect changes in pressure through these sensory hairs.
  • A unique feature manatees have amongst all mammals is the constant replacement of their molar teeth, called “marching molars”. New teeth are consistently entering the back of their mouth, replacing the old worn-out molars in the front.
  • When swimming, manatees sometimes do flips underwater or roll about, and they even swim upside down.
  • “Manatee” is from a Taíno word (pre-Columbian people who lived in the Caribbean) “manatí,” which means "breast."

Coloring Pages


1. Amazonian Manatee Wikipedia article -
2. Amazonian Manatee on The IUCN Red List site -

More Fascinating Animals to Learn About