Manatees

Gorp.com

Thought to be gentle because it had never had a predator, the West Indian manatee (Trichechus manatus) met up with one in the 1500s when Spanish colonists hunted and killed the large sea mammals for their meat, leather, and oil. Low population levels led Florida to ban manatee hunting in 1893, but recovery of the species was limited by shrunken populations and the subsequent losses of habitat. That led to manatees being listed as an endangered species. Sanctuaries, public education, and strict enforcement of low motorboat speeds are now the principal conservation measures being used to help build a sustainable population.

Estimated to number 2,600 individuals in the United States, manatees are slow to reproduce. Females mature at five years of age and males at nine. Twins are rare, the gestation period is 13 months, and calves can be dependent on mothers for 5 years.

The average adult weights 1,000 pounds and is 10 feet long. They feed exclusively on aquatic vegetation at the bottom or along the surface, propelling themselves with their paddle-shaped tail and using their under-developed flippers for balance and help in moving along water bottoms. The slow-moving mammal is completely defenseless and spends most of its time feeding and resting. When active, they surface every few minutes to breathe, every 10 to 15 minutes when resting. Their valve-like nostrils close tightly when submerged.

Manatee Facts
Description: Large, seal-like body that tapers to a spatulate tail. Two forelimbs with three or four nails on each. Skin thick and wrinkled with stiff whiskers on upper lip.
Size: Typically 10 feet long, weighing 1,000 pounds. Can grow as large as 13 feet, weighing more than 3,000 pounds.
Behavior: Gentle and slow moving. Most of their time is spent eating, resting, and in travel. Often shy and reclusive. No system of defense and completely harmless.
Sight: Depth perception may be limited. Can differentiate colors.
Hearing: Can hear very well despite the absence of external ear lobes.
Communication: Emit sounds that are within human auditory range. They make sounds such as squeaks and squeals when frightened, playing, or communicating, particularly between cow and calf.
Habitat: They can be found in shallow, slow-moving rivers, estuaries, saltwater bays, canals, and coastal areas, particularly where seagrass beds flourish.
Range: Within the United States they are concentrated in Florida during the winter, but can be found in summer months as far west as Alabama and as far north as Virginia. The West Indian manatee can also be found in the coastal and inland waterways of Central and South America as far south as Recife, Brazil.
Food Source: Aquatic plants. Manatees are completely herbivorous and can eat 10-15% of their body weight daily.
History: Manatees are believed to have evolved from a wading, plant-eating animal, and share a common ancestor with the elephant.

Often unseen by boaters, the manatees' slow motions prevent quick escapes from collisions. According to Crystal River NWR manager Shaw, an impact can easily damage the manatee's rib cage and cause lung collapse. Barring accidents, manatees are believed to live 60 years or more.

Concentrated in Florida in winter where there is spring-fed warm water that this tropical animal needs to survive, in the summer they go as far west as Alabama and as far north as Virginia. Elephants are their closest living relative.

During times of heavy manatee concentrations, certain areas in Kings Bay are designated, "Manatee Sanctuary Areas." These sanctuaries provide places for manatees to rest and feed undisturbed in the warmth of the springs.

In an effort to reduce the number of manatees killed and injured by boats, idle and slow speed zones are in effect throughout Kings Bay.

The U.S. Fish and Wildlife Service regularly monitors manatee abundance in the Crystal, Homosassa, Chassahowitzka and Withlacoochee Rivers. Aerial counts are flown once a month in the summer and once weekly in the winter.

Many manatees bear scars where they have been struck by boats and their propellers. These scars are so common and distinctive that U.S. Fish and Wildlife researchers use them for recognition and identification of individuals.

The Service currently has a volunteer program called "Manatee Watch." These volunteers provide the refuge staff with assistance in educating visitors about sanctuary locations and boating speed zones to better protect the manatee.

Calendar of Manatee Activities
Manatees are abundant throughout coastal and inland waters of Florida. During times of cold weather, manatees will concentrate in warm natural springs or in warm water discharges from power plants, both essential for their survival. Crystal River is special because it supports the largest concentration of manatees in a natural spring area. Individual manatees often return to the same wintering areas year after year.

December to March is the best time to see manatees. The weather is at its coolest and manatees are the most concentrated around the warm water springs that they depend on for their survival.

The refuge is accessible only by boat and visitors are encouraged to plan ahead and make reservations with one of the many dive shops and marinas in the town of Crysal River for a manatee/snorkel tour.

Manatee Manners
Passive observation (observing from a distance) is the best way to protect manatees and all wildlife. If you see manatees while swimming, diving, or boating, please follow these suggestions:

Do not enter designated manatee sanctuaries for any reason. Sanctuaries are in effect from November 15-March 31.

Operate boat at idle and slow speed where posted speed zones are in effect.

Observe manatees from the surface of the water and at a distance. Manatees on the bottom are likely to be resting or feeding.

Avoid excessive noise and splashing.

Use snorkel gear when attempting to watch manatees—the sound of scuba gear may cause them to leave the area.

Do not feed manatees or give them water.

Never ride, chase, poke or surround manatee.

Never separate a mother and calf or an individual from the group.


Published: 29 Apr 2002 | Last Updated: 15 Sep 2010
Details mentioned in this article were accurate at the time of publication

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