Amazonian Manatee (Trichechus inunguis)

Captive-Amazonian-manatee-showing-ventral-patterns

  • Name: Amazonian manatee
  • Latin: Trichechus inunguis
  • Classification: Mammal
  • Origin: South America
  • Lifespan: 50-60 years
  • AKA: South American manatee, yara

Taxonomy

  • Kingdom: Animalia (Animals)
  • Phylum: Chordata (Vertebrates)
  • Class: Mammalia (Mammals)
  • Order: Sirenia (Fully aquatic, herbivorous mammals)
  • Family: Trichechidae (Sea cows)
  • Genus: Trichechus (Manatee)
  • Species: Trichechus inunguis (Amazonian manatee)

Appearance

Length: 2-8m (9.2ft)
Weight: 360-540kg (790-1,200lbs)

The manatee is a large, cylinder shaped animal where the general coloration is grey, although most Amazonian manatees have a distinct white or bright pink patch on the chest. The forelimbs have been modified into flippers and have a flat, rounded, horizontal paddle at the rear. The upper lip has evolved into a large, bristly surface.

Relatives

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  • West Indian manatee (Trichechus manatus) -VULNERABLE-
  • West African manatee (Trichechus senegalensis) -VULNERABLE-
  • Dwarf manatee (Trichechus pygmaeus) -NOT RECOGNISED-

Habitat & Distribution

The Amazonian manatee occurs exclusively in freshwater and is the only manatee to do so. It prefers blackwater lakes, oxbows and lagoons. They seem to live most successfully in temperatures of 22-30’C (72-86’F).

The Amazonian manatees range is throughout the Amazon River Basin of South America, its range is also said to include the Orinoco River Basin.

map
Map of distribution of the Amazonian manatee

Diet

Manatees are primarily herbivores and feed on a variety of submerged, emergent, floating and shoreline vegetation and they will consume about 4-9% of their body weight in wet vegetation every day. Amazonian manatees fast during the dry season (November and December) and live off their fat reserves, also, because of their low metabolic rate; Amazonian manatees can fast for up to seven months if necessary.

Manatees can feed off the bottom, in the water column and at the surface. They can crop overhanging branches, consume acorns and partially haul themselves out of the water to eat bank vegetation, such as the leaves of mangrove trees. Manatees use their front flippers to manipulate this vegetation.

All manatees require a source of fresh water for drinking. Manatees have been seen drinking from hoses and sewage outlets and will congregate at river mouths to drink. Amazonian manatees do not have this problem as they live in fresh water lakes and rivers.

Behaviour

Amazonian manatees live almost entirely underwater and are active both day and night. They are gregarious and can be found in small groups of 8-10 individuals. They are herbivorous, aquatic mammals and their diet consists of aquatic vegetation such as emergent grass, water lettuce and floating vegetation, which grows near lake edges. These animals can consume up to 8% of their body weight in food every day.

Reproduction

The gestation period of an Amazonian manatee is one year. Breeding has been reported to occur throughout the year but reproduction in the Central Amazon Basin is seasonal as nearly all births take place from December – July (mainly from February – May when the water level rises).
A female manatee will give birth to one calf every two years. The calf will measure about 30 inches (80 cm) at birth. It will begin to nurse after a few hours by suckling from a teat under the pectoral flippers and will do so underwater.

The young will be weaned after a year but will remain with their mothers for two. The young learn about feeding and resting areas from their mother, as well as travel routes and warm-water refugees. The female manatees will carry their young on their back or clasped onto their sides.

Adaptations

  1. The manatee has muscular lips which it uses with its front flippers to grab food and pull it into its mouth.
  2. The Amazonian manatee has a large paddle like tail which helps propel it through the water. It moves at 5mph but can reach speeds of up to 15mph.
  3. The manatee has thick stubby bristles on this mouth. This helps it to uproot foot on the river bed.
  4. The manatees body is streamlined which helps reduce drag when travelling through the water.

Threats

The Amazonian manatee’s main threat is hunting by subsistence and commercial hunters. They have been sought for their meat, oil and fat, and in the past, its hide, which could be used for water hoses and belts. Other threats to this creature include accidental drowning in commercial fishing nets and degradation of food supplies by soil erosion, which is caused by deforestation.

Conservation

IUCN Status: Vulnerable

International trade of the Amazonian manatee and any of its products is prohibited under Appendix I of CITES. Other local projects and organizations helping to conserve the manatee include Projeto Peixe-Boi / Centre for Aquatic Mammals, Mamiraua Project and The Friends of the Manatee Association. Amazonian manatee hunting has been prohibited since 1973; however, its population trend is still decreasing.

Fun Facts

Male: Bull
Female: Cow
Young: Calf
Group: Herd, Pod

-Manatees are closely related to elephants,
-Another name for the Amazonian manatee is Yara, which is a Brazilian Indian word meaning ‘Lady of the Water’.
-Manatees are believed to be the origin of the mermaid myths.

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