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What Manatees Eat

Manatees, referred to popularly as sea cows, are marine mammals. There are three species of this creature: the African manatee, the Amazonian manatee and the West Indian manatee. All three of these species are primarily herbivorous, existing on a variety of aquatic plant life. They do, however, ingest various macro-invertebrates incidentally, and there is some evidence of deliberate carnivorous activity among the West Indian variety. Manatees commonly consume the equivalent of 9% of their body weight every day. They prefer to feed on surface vegetation in shallow waters because they do not have a thick layer of fat and deep sea feeding uses valuable energy reserves.

The West Indian Manatee
- West Indian manatees are the largest species of manatee. They are mainly found in warm bodies of freshwater and saltwater in the United States but have also been observed in Central and South America.
  
  They feed on a wide variety of submerged freshwater plants in the wild, including eelgrass, hydrilla and wigeon grass, saltwater plants such as turtle grass and shoal weed and bank plants including paragrass and cowpea. While primarily herbivorous, the West Indian manatee also ingests insect larvae, molluscs, shrimp and other vegetation dwelling macro-invertebrates incidentally while eating.
  
  In a 2003 article in the journal "Aquatic Mammals," Sarah Corby and Graham Worthy published research calling into question the assertion that manatees are true herbivores after observing West Indian manatees intentionally eating invertebrates.
The African Manatee
- African manatees are found in freshwater along the west coast of Africa. They have been found as far upstream as the Niger River in Mali. They are herbivores and eat a variety of vegetation. Because submerged plant life is not as abundant in West Africa as in the Americas, African manatees depend on overhanging or bank vegetation such as mangroves. Woodcutting of mangrove trees has severely threatened their existence, while in Sierra Leone they are routinely killed by farmers who consider them a pest because of their habit of grazing in the rice fields that dot the waterways of that country.
The Amazonian Manatee
- Amazonian manatees live exclusively in the freshwater lakes, lagoons and rivers of the Amazon River Basin. The Amazonian manatee is unique among the manatee species in that it does the majority of its feeding during the rainy season (April to August) when the plant life it requires to survive is at its most abundant. During this period the Amazonian manatee will eat for around eight hours per day. Research published in "Biotropica" suggests that this allows the Amazonian manatee, which has greater fat reserves than other species, to fast for periods as long as seven months during the dry season. However, increased deforestation in the Amazon severely threatens the food supply of the Amazonian manatee even during the rainy season.
Manatee Calves
- Manatee calves feed on their mother's milk within a few hours of birth. This milk contains mostly water with around 7% protein and 13% lipid fat content. While they may continue to breastfeed for as long as a year, calves begin eating plants at around one or two weeks of age.

Animals & Science