West Indian Manatee

West Indian Manatee

Sea cow

Kingdom
Phylum
Subphylum
Class
Order
Family
Genus
SPECIES
Trichechus manatus
Population size
below 10,000
Life Span
28-60 yrs
TOP SPEED
22 km/h
WEIGHT
200-600 kg
LENGTH
2.5-4.5 m

When travelling to America, Christopher Columbus mistook this aquatic mammal for a mermaid. The West Indian manatee has a large, round body that tapers to the tail and tough skin, which is colored in grey-brown. The body and muzzle bristles of this animal exhibit sparsely distributed hairs. The forelimbs of the West Indian manatee are short flippers. This animal has a paddle-shaped tail, as opposed to closely related dugong which displays a fluke-like tail. One of the noteworthy facts about this species is the continuous replacement of the molar teeth. Usually, new teeth emerge at the back of the jaw, replacing worn teeth at the front. According to some studies, West Indian manatee has sensory hairs, which are likely to provide the animal with a sixth sense and allow to detect pressure changes.

Distibution

The West Indian manatees occur in a huge territory, from the mid-Atlantic region of the United States across the Caribbean Sea and Gulf of Mexico, southwards to coastal regions of northeastern and central-eastern South America to northeastern Brazil. These animals can live in both clear and muddy waters. They occur in freshwater, estuarine and marine waters at depths of more than 1 - 2 meters. Preferred habitats are coastal areas, canals, rivers, estuaries and saltwater bays.

West Indian Manatee habitat map

Climate zones

Habits and Lifestyle

The West Indian manatees are non-territorial and solitary animals, which may occasionally be observed in loosely organized, temporary concentrations. When gathering into these groups, they usually display no social hierarchy. As nomadic animals, West Indian manatees are constantly on the move, travelling from one place to another to find food. These animals may be active at any time of the day. The West Indian manatees rest for several hours at a time. They may rest both at the water's surface and at the sea floor. Meanwhile, they have to regularly come to the surface for air (every few minutes) when resting on the sea floor. These animals are able to remain underwater for up to 15 minutes, though generally dive for about 4 minutes. The West Indian manatees are very agile and playful animals, known to perform maneuvers such as somersaults, rolls and swimming upside-down. They are normally not vocal animals, but can occasionally vocalize, emitting squeals, chirps, and screams.

Group name

Diet and Nutrition

The West Indian manatee are primarily herbivorous. The diet of this animal generally consists of sea grasses and plant leaves, found on the sea floor.

Mating Habits

MATING BEHAVIOR
REPRODUCTION SEASON
Year-round
PREGNANCY DURATION
12 months
BABY CARRYING
1 calf
INDEPENDENT AGE
2 years
FEMALE NAME
cow
MALE NAME
bull
BABY NAME
calf

The West Indian manatees have a polygynous mating system. Breeding occurs in groups, consisting of a single female and several males that may pursue her from a week to a month. These animals have no defined breeding season, mating year-round. Gestation period lasts for about 1 year, yielding a single baby. Within the first few weeks of its life, the newborn manatee starts consuming vegetation. The weaning occurs at 2 years old, by which time the calf already knows the feeding areas and migration routes of its species. The age of sexual maturity is 9 - 10 years old for males and 4 years old for females. Meanwhile, males are ready to mate at 2 years old, whereas females are capable of producing offspring only after 7 years old, usually giving birth every 2 - 5 years.

Population

Population threats

One of the major threats to the population of this species is frequent collisions with boats. Another concern is loss of warm water springs that are the natural habitat of these manatees. The animals are often entangled in fishing gear. In addition, they suffer from red tide blooms. On the other hand, pollutants cause reduction in the amount of seagrass, which is the main food source for the West Indian manatees. And finally, these vulnerable animals have a small population and a very low birth rate, which poses a serious threat to the future of this species.

Population number

According to the IUCN Red List, the total West Indian manatees’ population is currently estimated to a number less than 10,000 individuals, including the Florida manatee subspecies with population of less than 2,500 mature individuals as well as the Antillean manatee subspecies with current population of less than 2,500 mature individuals. Overall, West Indian manatees’ numbers are decreasing today, and the species is classified as Vulnerable (VU) on the IUCN Red List.

Fun Facts for Kids

  • The West Indian manatees belong to the order of 'Sirenia'. The word 'sirenia' originates from 'siren': according to Greek mythology, sirens were beautiful sea creatures, luring sailors to shipwreck with their enchanting songs.
  • Unlike humans, these animals don’t need to visit the dentist: their teeth constantly replace throughout their lives. New teeth emerge at the back of their jaw, while worn teeth fall at the front. To compare, humans have only one round of baby teeth, and hurt or lost teeth of adults don’t replace.
  • Many of the early explorers, including Christopher Columbus, claimed to have observed female figures in the ocean, probably inspired by the legend of mermaids, which was popular in the writings and drawings of their era. This unbelievable statement may have a simple explanation such as a trick of the light or extremely long stay at the sea. However, many of these apparitions obviously had to do with manatees.
  • Newborn offspring of this species have their complete set of teeth. Females will teach their calves to submerge and hold their breath for long periods of time.
  • The West Indian manatees possess a highly-developed vision, allowing them to locate objects from a distance of tens of meters away.

References

1. West Indian Manatee Wikipedia article - https://en.wikipedia.org/wiki/West_Indian_manatee
2. West Indian Manatee on The IUCN Red List site - http://www.iucnredlist.org/details/22103/0

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