West Indian manatees (Trichechus manatus) are related to elephants; manatees and elephants are believed to have evolved from the same ancestor. They are of the order of animals known as the Sirenia. (Look up "siren" in the dictionary.) The West Indian manatee occurs in Florida and in islands of the nearby Caribbean Sea. Other species of manatees are found in the Amazon River and in West Africa. Two other species of "sea cows" are also known.

The nomadic, essentially solitary, manatee seems equally at home in salt water and in fresh, though it probably prefers rivers and estuaries, and may require fresh water. (Manatees have been observed drinking fresh water from hoses hanging from piers.) They prefer to live in water 4 to 10 feet deep. In Florida, manatees may be found in coastal bays and inlets, in springs, in salt marshes, and in canals and undammed rivers throughout the state. Their movement is influenced by depth, salinity, tides, currents, access to warm water and by the availability of plant food. Manatees wander Florida's hundreds of miles of Atlantic and Gulf coastline, traveling from one river mouth to the next. They have been seen miles from shore, but generally cruise just beyond the breakers. In deep water, they may cruise at depths of 6-9 feet. In summer, they may cruise as far north as Virginia and as far west as Louisiana.

Manatees seem to be motivated to explore, according to D.S. Hartman, the expert on Florida's manatees. Manatees have been observed checking out every corner of a new canal system. This researcher said he cannot explain why manatees have a propensity to leave ample food and water, unless it is to explore.

Aquatic Plants Eaten by Manatees In the wild, manatees are known to prefer to eat these submersed freshwater plants, which are all found in Florida: eelgrass (Vallisneria americana) coontail (Ceratophyllum demursum) hydrilla (Hydrilla verticillata) Eurasian water milfoil (Myriophyllum spicatum) wigeon grass (Ruppia maritima) pondweed (Potamogeton pectinatus) Canadian waterweed (Elodea canadensis) Manatees also have been observed eating these bank plants: cattail (Typha domingensis) salt grass (Distichlis spicata) paragrass (Urochloa mutica) seashore paspalum (Paspalum vaginatum) saltmarsh cordgrass (Spartina alterniflora) cowpea (Vigna repens) Manatees in the wild: will eat floating water hyacinth (Eichhornia crassipes) and alligatorweed (Alternanthera philoxeroides) if there are no underwater plants available will eat algae, especially green algae, or plants on the bank if no other plants are available Manatees are also known to prefer these saltwater submersed plants found in Florida: manatee grass (Syringodium filiforme) turtle grass (Thalassia testudinum) shoal weed (Halodule wrightii) Manatees in captivity have eaten: lawn grass (Poa sp.) dandelions (Taraxacum officinale) sow-thistle (Sonchus oleraceus) palmetto fronds (Sabal palmetto) most of the garden vegetables cultivated legumes many commercial fruits and even bread, fish and meat Manatees seem to avoid the freshwater plants, water lettuce (Pistia stratiotes), water lilies (Nymphaea sp.), water ferns (Azolla caroliniana and Salvinia sp.) and spatterdock (Nuphar advena).

WHAT'S FOR DINNER?
Manatees apparently will try to eat any plants. They have been observed eating aquatic plants, and shore plants, including trees, hanging out over the water. They are also known to eat an ocassional fish. They have been observed drifting in the current, casually snatching and eating plants as the current pushed them along. They chew incessantly; the sound of their teeth grinding is audible underwater.

Manatees usually eat about 10% of their body weight per day in fresh plants, but sometimes will eat up to one fourth their body weight per day. That is, if the animal weighs 1,000 pounds, it will eat 100 to 250 pounds of fresh plants per day.

Though manatees are described as "herbivorous", they sometimes do eat fish. (And in captivity have eaten meat.) Also as manatees browse aquatic plants, they are also eating (and gaining protein from) the small animals that are on the plants, including shrimp, crayfish, crabs, insects, snails, leeches, nematodes, worms, anemones and star fish.

MANATEES and AQUATIC PLANT MANAGEMENT
Environmental management agencies in Florida routinely must consider the needs of water animals when devising plant management strategies. This is especially true when working in rivers, springs and marshes where manatees may be.

For example, King's Bay at Crystal River is a major refuge of Florida's manatees. In King's Bay, copper-based herbicides are not used for plant and algae control because of the unknown effects that might be caused if manatees ate aquatic weeds that have been treated with copper.

Aquatic plant managers in Florida also are careful while driving their boats; and careful when spray applying or "injecting" aquatic herbicides, lest they contaminate manatees themselves or treat plants that manatees are about to eat.

MANATEE MISCELLANEA

Manatees are mammals; baby manatees drink manatee milk by suckling one of the mother's teats.

Sound seems to be the principal sense of the manatee. In fact, manatees speak to one another, or at least make squeaky squeals, chirp-squeaks and screams. They make these sounds when irritated, frightened, and while playing. Their sounds are apparently non-navigational, as some sounds are in whales.

The manatee has fairly good eyesight and can see at night as well as it sees in the day. It blinks its eyes frequently to lubricate them with oil from oil glands near the eyes.

Manatees in Florida breed year-round, and give birth during any month of the year. Gestation is about 13 months. The single baby (calf) will stay with its mother for 1-to-2 years. Sexual maturity is at 3-to-4 years. Manatees may live to be 50 years old.

Manatees hold their breath while under water. They breathe by rising to the surface, opening the nostrils to exhale, instantly taking another single breath through the nostrils, and then closing the nostrils just as it re-submerges. Smaller manatees may hold their breath on average for four-and-a-half minutes while larger animals may hold their breath for 10-to-12 minutes.

During courtship, manatee bulls will follow manatee cows, mouthing and embracing her. As many as 17 bulls once were observed following an estrous cow. The cow can become irritated enough by this to actually knock a bull to the surface with her tail. Sometimes the cow will nearly beach herself to get away from pursuing males. Manatees mate during a 30-second belly to belly embrace. Male homosexual activity is observed frequently, but not female homosexual activity.

Manatees at play, 2 or more at a time, will mouth, bump and kiss each other, embrace and roll over and over on each other in the water.

At rest, manatees will close their eyes and either hang suspended at the surface or lie prostrate on the bottom. They open their eyes to surface to take a breath and close their eyes again when going back to rest. They may rest for only 2 hours a day, or as many as 12 hours, but generally rest 6-to-10 hours in 2-to-4 hour sessions during a 24-hour period.

Water depth caused by tides influences when and where manatees forage. These half-ton animals can swim in surprisingly little water, as shallow as 3 feet, and sometimes even less.

Manatees do not keep regular hours - they do not choose night for resting or day for feeding - they feed, rest and play anytime during the day and night.

They feed 6-to-8 hours a day in sessions of 1-to-2 hours.

Manatees like to stretch, especially when resting, and may be seen arching their backs upward or downward in a variety of stretching positions.

Manatees like to scratch themselves, and may use their flippers to do so, or may rub their backs, bellies and faces against logs, poles, limestone outcrops, buoy lines, anchor ropes, crab traps, boat hulls and propeller blades.

Manatees like to clean their mouths, sometimes using their flippers to remove plant pieces caught inside.

Manatees are frequently hit by boats and lacerated by engine propellers. Researchers take pictures of scar patterns as a means to identify individual study-animals as they migrate around the state.

Manatees like to "root" in the bottom, sucking in a mixture of sand and water then spitting it out. They may do this for an hour at a time.

Manatees sometimes sneeze, resulting in an explosion of bubbles.

In the warm months, manatees may go for days without seeing another manatee. In the cold months, they congretate and socialize frequently. However, they are essentially solitary-minded animals.

Manatee swim velocity ranges: idling at 2-to-3 km/hr; cruising at 3-to-7 km/hr; and fleeing at 18-to-25 km/hr.

Manatees swim by stroking their tails in the water. For cruising, the manatee tail may stroke 20 to 36 strokes per minute. Fleeing manatees may stroke their tails up to 50 times per minute. The tail also acts as a rudder.

Manatees use their flippers to move about on the bottom (as if "walking"), to balance, to steer and even to grasp plants and objects.

Manatees are not particularly interested in other animals. They have been seen in encounters with otters, dolphins and alligators, and they completely ignored them.

On the other hand, manatees often seem interested in inanimate objects. They may find beer cans, bottles, driftwood and other items on the bottom and then carry the objects around or nibble them. Unfortunately, they sometimes also swim up to examine boats, and boat propellers.

THEY LIKE IT WARM
Manatees are mainly tropical animals. In subtropical Florida, they sometimes experience conditions that are too cold for them. Even with their insulating layer of blubber, manatees are not happy where the water temperature is less than 19 or 20 degrees C (65 to 66 degrees F), and will avoid water temperatues less than about 13 degrees C (56 degrees F). During winter cold-spells, when the air temperatures drop to 10-15 degrees C (50 to 60 degrees F), these cold-sensitive animals congregate in springs and spring runs as well as in the warm discharge waters of nuclear power plants. In very cold winters in Florida, manatees catch pleurisy and bronchial pneumonia and do succumb.