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Scientific Classification
→ Scientific Manatee Classification Scientific Classification
Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication Class Mammalia Behavior
Diet & Eating Habits
Reproduction Order Sirenia
Birth & Care of Young 1. The living sirenians consist of three species of manatees and one species of dugong.
Longevity & Causes of 2. The Greek name for this order is derived from the sirens of Greek mythology. Sirens were sea nymphs Death who lured sailors to their island with their mesmerizing songs.
Conservation & Research
Appendix
Books For Young Readers
Bibliography
Sirenians are named for the sirens of Greek mythology.
Family Trichechidae And Dugongidae
1. All three species of manatees belong to the family Trichechidae.
2. The family Dugongidae includes the dugong found in the Indian and western Pacific Oceans. A second species, the Steller's sea cow was discovered in 1741 and hunted to extinction by 1768. This species lived primarily in the Commander Islands of the western Bering Sea.
Genus, Species
1. Trichechus manatus, the West Indian manatee. There are two subspecies of the West Indian manatee: the Florida manatee (Trichechus manatus latirostris) and the Antillean manatee (Trichechus manatus manatus). These subspecies are distinguished by differences in cranial measurements and by their geographic distribution.
2. Trichechus senegalensis, the West African manatee. About the same size and shape of the West Indian manatee, the West African manatee differs in some important respects: position of the eyes, snout, and cranial bones. 3. Trichechus inunguis, the Amazonian manatee. The Amazonian manatee is the smallest of the manatees. Several physical characteristics distinguish it from the other two species. It lacks nails on its pectoral fins, and usually has whitish patches on its underside.
Fossil Record http://seaworld.org/en/animal-info/animal-infobooks/manatee/scientific-classification/ 1/2 1/10/2015 seaworld.org/en/animal-info/animal-infobooks/manatee/scientific-classification/ 1. The fossil record of sirenians is incomplete, and the relationship between manatees and their ancestors is poorly known.
Sirenian fossil records are incomplete and continue to be an area of study.
2. Even though the oldest known sirenian fossils were found in Jamaica (Prorastomus sirenoides), it is likely that sirenians originated in Eurasia or Africa. During the middle Eocene period (45 to 50 million years ago), the ancestors of manatees probably reached South America (Savage et al., 1994). 3. Studies using biochemical analysis of proteins show that the closest modern relatives of sirenians are elephants, aardvarks, and small mammals known as hyraxes. These four orders of mammals are sometimes considered "subungulates", meaning they may be evolutionary offshoots of a primitive ungulate (hoof) stock. The anatomical characteristics they share include the lack of a collar bone and the presence of nails instead of claws. Scientists once mistakenly thought manatees were closely related to walruses based on facial similarities (Reynolds and Odell, 1991).
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Habitat & Distribution
Scientific Classification Manatee Habitat & Distribution → Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication Distribution Behavior
Diet & Eating Habits 1. All living sirenians are found in warm tropical and subtropical waters (Nowak and Paradiso, 1983).
Reproduction
Birth & Care of Young
Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Readers
Bibliography Manatees and dugongs are found in warm waters around the world. In the United States, manatees are most common in Florida waters.
2. The West Indian manatee was once abundant throughout the tropic and subtropical western North and South Atlantic and Caribbean waters. However, the manatee's numbers have been greatly reduced. Today, the West Indian manatee is listed as an endangered species throughout its range.
The range of the Florida manatee is primarily peninsular Florida but extends as far north as Rhode Island. Manatees have been rescued near Houston, Texas, and Mississippi.
Antillean manatees have a patchy distribution throughout the Caribbean, Mexico, and northeastern South America. The southern range extends through Central and South America to Brazil.
3. West African manatees range from Senegal to Angola, on the west coast of Africa.
Amazonian manatees are the only species of manatee confined to fresh water. They inhabit the Amazon Basin, mostly in Brazil. They are uncommon or close to extinction in Peru, Ecuador, and Colombia.
Habitat
1. The West Indian and West African manatees inhabit rivers, bays, canals, estuaries, and coastal areas rich in seagrass and other vegetation. They can live in fresh, saline (salt), and brackish waters. They move freely between extremes.
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West Indian manatees freely move between fresh, brackish, and saline waters.
West Indian manatees may be found in any waterway over 1 m (3.25 ft.) deep and connected to the coast. They prefer waters with temperatures above 21°C (70°F). Florida manatees rarely venture into deep ocean waters. However, manatees have been spotted as far offshore as the Dry Tortugas Islands, approximately 81 km (50 mi.) west of Key West, Florida.
West African manatees live in quiet coastal areas, large rivers, lagoons, and connected lakes, where the water temperature is above 18°C (64°F). 2. The Amazonian manatee is restricted to fresh water. They are most common in floodplain lakes and channels in white-water river systems with water temperatures ranging from 25°-30°C (77°-86°F). 3. The patchy distribution of manatees throughout all their ranges is due to their search of suitable habitat: plentiful aquatic plants and a freshwater source of water to drink.
Migration
1. Florida manatees move into warmer waters when the water temperature drops below about 20°C (68°F).
Manatee calves learn migration routes and the locations of warm water areas from their mothers.
Historically, Florida manatees have migrated south into warmer waters during the colder months of the year. On the Gulf coast, manatees congregated at natural warm-water springs. On the Atlantic coast, manatees headed south of the Sebastian River.
Today, power plant outfalls and other warm-water discharges are important winter destinations for many manatees.
In Florida, more than 200 manatees congregate at some power plants during cold weather. These artificially heated sources have allowed manatees to remain north of their historic wintering grounds.
Among the most important of the artificial warm-water discharges are the Florida Power & Light Company's power plants at Cape Canaveral, Fort Lauderdale, Port Everglades, Riviera Beach, and Fort Myers, as well as the Tampa Electric Company's Apollo Beach power plant in Tampa Bay, Florida (Van Meter, 1989). 2. In dry seasons, West African and Amazonian manatees migrate downstream or into lakes or deeper parts of a river. http://seaworld.org/en/animal-info/animal-infobooks/manatee/habitat-and-distribution/ 2/3 1/10/2015 seaworld.org/en/animal-info/animal-infobooks/manatee/habitat-and-distribution/ 3. One manatee known as "Chessie" traveled 3,220 km (2,000 mi.) from Florida to Point Judith, Rhode Island, and back in 1996. Chessie migrated further north and covered a greater distance than any manatee ever documented.
Population
1. The Florida manatee census taken in January, 2000, found 2,222 individuals. The 1999 survey was 2,353. Scientists believe there may be as many as 3,000 manatees currently in the state of Florida. 2. Populations of all species of manatees have apparently declined over the past hundred years. These declines are due to such causes as hunting for their meat, destruction of their habitats, boating, pollution, and low reproduction rates. Antillean, Amazonian, and West African manatee populations are not known due to inadequate scientific research.
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Physical Characteristics
Scientific Classification Manatee Physical Characteristics Habitat & Distribution
→ Physical Characteristics
Senses
Adaptations
Communication Size Behavior
Diet & Eating Habits 1. Adult West Indian and West African manatees average about 3 m (10 ft.) in length. Large individuals may reach lengths of up to 4 m (13 ft.). Average adult weights are approximately 363 to 544 kg (800- Reproduction 1,200 lb.). One particularly large Florida manatee weighed 1,655 kg (3,650 lb.). Females are generally larger than males. Birth & Care of Young
Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Readers
Bibliography Adult West Indian manatees average about 3 m (10 ft.) and weigh approximately 363 to 544 kg (800 to 1,200 lb.).
2. Amazonian manatees are the smallest of all three species. They are shorter and more slender. The longest specimen measured 2.8 m (9.2 ft.). A large individual weighed 480 kg (1,058 lb.).
Body Shape
1. The manatee's body is streamlined-full around the middle and narrowing to a paddle-shaped tail.
Coloration
1. The true color of a manatee is gray, although it may appear brownish-gray.
2. Amazonian manatees usually have white or pink patches on the belly and chest.
3. Organisms such as algae, which may grow on the skin of slow-moving individuals, alter the body color and make some manatees look more green or brown.
Pectoral Flippers
1. ASDF
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Manatees have small, flexible pectoral flippers that are used for steering, touching, scratching, and even embracing.
2. West Indian and West African manatees have three or four fingernail-like the toenails on an elephant's feet-at the tips of their flippers. Amazonian manatees lack fingernails. 3. Manatee flippers have five digits that are covered by a thick layer of skin. This bone structure is similar to that of toothed whales, seals, and sea lions.
Hind Limbs
1. Hind limbs are absent. Vestigial pelvic bones, which are not connected to the vertebral column, are found deep in the pelvic musculature.
Head
1. Manatees have no external discernable neck. 2. Manatees do not have external ear flaps. The tiny opening to the ear canal is located several centimeters behind the eye. 3. The nostrils lie at the end of the snout on the upper surface. They close automatically when a manatee submerges.
Manatee nostrils close automatically when it submerges.
4. Manatees have a large flexible upper lip. Their lips help guide vegetation into the mouth. Vibrissae (whiskers) are found on the surface of the upper lip. Each vibrissa is separately attached to nerve endings and has its own supply of blood.
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5. Small eyes (about 2 cm or 0.8 in. in diameter) are located on the sides of the head. The iris has a color ranging from blue to brown (Griebel and Schmid, 1996). 6. A manatee's only teeth are 24 to 32 molars located in the back of the mouth. The front molars in each row are continually being worn down by the abrasive plants the manatee eats. As the teeth wear down, new molars grow in the back of the mouth and gradually move forward. The replacement process continually provides new chewing surfaces as the teeth wear down, and continues throughout the manatee's lifetime. This unusual dental adaptation is found only in the modern manatees, suggesting that the manatee diet at an earlier time was extremely abrasive.
The front molars in a manatee's mouth are continually worn down by the abrasive plants it eats.
7. In addition to molars, manatees have horny, ridged pads at the front of the upper and lower jaws which aid in crushing plant materials.
Tail
1. The tail is evenly rounded and forms a paddle shape.
Manatees have rounded, paddle-shaped tails.
2. A manatee swims by moving its large paddle-like tail in an up-and-down motion.
Hair
1. A manatee has sparse hairs scattered over its body, with the largest concentration around the snout area.
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Manatees have a concentration of hairs around their snouts as well as scattered over their bodies. A substantial nerve network transmits tactile information from these vibrissae to the brain.
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Senses
Scientific Classification Manatee Senses Habitat & Distribution
Physical Characteristics
→ Senses
Adaptations
Communication
Behavior Hearing Diet & Eating Habits 1. The hearing capacities of manatees are not well studied, but it is known that manatees are adapted for Reproduction hearing low frequency sounds. 2. Manatees have large ear bones that are well developed at birth. Some scientists have suggested, Birth & Care of Young however, that the main area of sound reception is not the small ear openings but rather an area near the cheekbones. A manatee's cheekbones are large and relatively oily, and they are in direct contact with Longevity & Causes of the ear bones. Death 3. Hearing is an important sense for young manatees because mother and calf vocalizations are significant Conservation & in keeping them together. The chirps, whistles, and squeaks used by manatees are probably produced in Research the larynx and are often in the 3-5 kHz range. 4. Preliminary studies suggest that manatees have a greater sensitivity to low-frequency sound than any Appendix marine mammal studied (U.S. Fish and Wildlife Service, 1995). Books For Young Readers Eyesight
Bibliography 1. Manatees have well-developed eyes. In the water, they can detect objects from tens of meters away. 2. A manatee's retinas contain both rod and cone cells, indicating that they probably have the ability to see both dim and bright light. Recent tests suggest manatees can distinguish between blue and green colors, although the full extent of their color vision is unknown and more studies are needed.
Recent tests suggest manatees can distinguish between blue and green colors.
3. A nictitating membrane acts as an extra eyelid for protection.
Tactile
1. Touch seems to be very important for manatees. Body contact is common between mother and calf. Manatees have also occasionally been observed initiating body contact with divers. They have even been seen making contact with inanimate objects such as ropes, buoys, logs, and rocks.
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Touch seems to be important for manatees. They have been observed making contact with a variety of inanimate objects.
Taste and Smell
1. The manatee's chemoreceptive capacities (taste and smell) have not been well studied. They have taste buds on the backs of their tongues and can most likely taste. Studies on manatee food preference at Blue Spring State Park, Florida, indicate that manatees avoid certain plants such as spatter dock, blue- green algae, and waterpennywort that contain natural toxins. 2. Manatees have olfactory tissue on small internal nasal bones, and probably have some sense of smell. The capability for scent discrimination is largely unknown. 3. Some researchers theorize manatees use smell and/or taste to tell if a female is in estrus or "heat", while other researchers believe males respond to low frequency sounds made by females when they are ready to mate.
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Adaptations
Scientific Classification Manatee Adaptations for an Aquatic Environment Habitat & Distribution
Physical Characteristics
Senses
→ Adaptations
Communication
Behavior Swimming Diet & Eating Habits 1. Manatees are quite agile and maneuver well under water.
Reproduction 2. Florida manatees have been clocked swimming at speeds up to 24 kph (15 mph) for short bursts, but usually cruise about 3 to 10 kph (2-6 mph) or less. Birth & Care of Young
Longevity & Causes of Diving Death 1. Although manatees are excellent swimmers, the deepest an individual has been seen diving is 10 m (33 Conservation & ft.). They normally feed no deeper than about 3 m (10 ft.) below the surface of the water. Research
Appendix
Books For Young Readers
Bibliography
The vegetation manatees eat does not grow in deep water, so manatees feed mostly in waters no deeper than 3 m (10 ft.).
2. All marine mammals have special physiological adaptations for diving. These adaptations enable a manatee to conserve oxygen while under water.
Manatees, like other marine mammals, have a slower heart rate while diving.
In contrast to whales and dolphins, manatees are not deep-diving marine mammals. Therefore, manatees' muscles do not contain the high concentrations of the oxygen-binding protein myoglobin that is typical of other marine mammals.
Respiration
1. Studies show that manatees renew about 90% of the air in their lungs in a single breath (humans renew only about 17%). 2. While resting, manatees can stay submerged for as long as 20 minutes, although the average interval between breaths for resting is two to three minutes. More active and smaller manatees breathe more often.
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Manatees must surface to breathe. The average interval between breaths is two to three minutes.
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Communication
Scientific Classification Manatee Communication Habitat & Distribution
Physical Characteristics
Senses
Adaptations
→ Communication
Behavior Sound Production Diet & Eating Habits 1. Manatees emit sounds under water. The chirps, whistles, or squeaks are probably produced in the Reproduction larynx. They seem to make these sounds when they are frightened, sexually aroused, or interacting with each other. Birth & Care of Young 2. Vocalizations are an integral part of the cow-calf relationship. Cows respond to squeals of their calves from more than 61 m (200 ft.) away. Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Readers
Bibliography
Manatee mothers have been known to respond to the squeals of their calves from 61 m (200 ft.) away.
Other Communication
1. Manatees may communicate through sound, sight, taste, touch, and smell.
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Behavior
Scientific Classification Manatee Behavior Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
→ Behavior Daily Activity Cycle Diet & Eating Habits 1. Manatees are nonaggressive, nonterritorial herbivores that spend most of their time feeding (six to Reproduction eight hours per day) and resting (two to twelve hours per day). The remainder of their day is spent traveling, investigating objects, and socializing by interacting with other manatees. Birth & Care of Young
Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Readers
Bibliography Manatees form loosely organized groups with individuals casually gathering and dispersing.
Social Behavior
1. Manatees are best described as semi-social. The basic social unit is a female and her calf. Groups of manatees gather and disperse casually. These groups tend to be temporary and vary regarding sex, number, or age. Manatees do congregate at winter warm-water refuges.
Manatees spend most of their day feeding and resting.
2. Manatees have been observed participating in loosely organized, seemingly playful activities such as bodysurfing and follow-the-leader.
Manatee bodysurfing involves groups of manatees riding the powerful currents generated below flood dams when the gates are partly open. Sessions of bodysurfing can last more than an hour. Bodysurfing manatees frequently nuzzle one another and vocalize between rides.
Follow-the-leader is another form of coordinated behavior in which two or more manatees move together in a single file. During this time they synchronize all of their activities including breathing, http://seaworld.org/en/animal-info/animal-infobooks/manatee/behavior/ 1/2 1/10/2015 seaworld.org/en/animal-info/animal-infobooks/manatee/behavior/ diving, and changing direction.
The basic manatee social unit is a female and her calf.
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Diet & Eating Habits
Scientific Classification Manatee Diet & Eating Habits Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Diet Preferences And Resources
→ Diet & Eating Habits 1. Manatees are primarily herbivores. They feed on a wide variety of submerged, emergent, floating, and Reproduction shoreline vegetation. 2. Manatees in Florida feed on more than 60 species of plants including turtle grass, manatee grass, shoal Birth & Care of Young grass, mangrove leaves, various algae, water hyacinth, acorns, and hydrilla. Longevity & Causes of 3. In Sierra Leone, Africa, the West African manatee is considered a pest because they consume fields of Death planted rice. 4. Manatees have occasionally been seen to eat foods other than plants. Antillean manatees have been Conservation & known to eat fish from nets and West African manatees have been known to eat clams (Reynolds and Research Odell, 1991). Appendix
Books For Young Readers
Bibliography
All manatees eat vegetation.
Food Intake
1. Manatees consume about 4% to 9% (15 to 49 kg or 32-108 lb. for an average adult manatee) of their body weight in wet vegetation daily.
2. Some Amazonian manatees living in deep bodies of water apparently fast during dry seasons (November and December) when water levels drop as much as 9 to 15 m (30-50 ft.), eliminating their access to vegetation.
3. Because manatees have a very low metabolic rate, it is speculated that Amazonian manatees are able to fast for up to seven months if necessary (O'Shea, 1994).
Method of Feeding
1. Manatees feed off the bottom, in the water column, and at the surface. They have been known to crop overhanging branches, consume acorns, and haul themselves partially out of the water to eat bank vegetation including the leaves of mangrove trees.
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Manatees feed off the bottom, in the water column, and at the surface.
2. Manatees use their front flippers and large, flexible lips to manipulate vegetation. 3. Horny, ridged pads at the front of a manatee's palate (roof of the mouth) and lower jaw break vegetation into smaller pieces. Behind the pads, molars grind the food.
Fresh Water
1. Both the West Indian and West African manatees may require a source of fresh water for drinking. Manatees have been seen drinking fresh water from hoses, sewage outfalls, culverts, and also congregating at river mouths. Most scientists agree that manatees must periodically have access to fresh water.
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Reproduction
Scientific Classification Manatee Reproduction Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Sexual Maturity Diet & Eating Habits 1. Male manatees (bulls) are sexually mature by about nine to ten years, although some have produced → Reproduction viable sperm at two to three years of age. 2. Female manatees (cows) are sexually mature as young as three years of age. Birth & Care of Young 3. As manatee aging studies progress, sexual maturity may be estimated more precisely. Longevity & Causes of 4. Although females are usually larger than males, it is very difficult to tell the sex of an individual animal Death without observing its underside. There is no marked sexual dimorphism other than the position of the genital openings. Conservation & Research The female's genital opening is located just in front of the anus. Two additional ways to identify a female are the presence of a suckling calf, or an extremely round appearance during pregnancy. Appendix The male's genital opening lies just behind the umbilicus (navel), about midway down the underside Books For Young of the body. Readers
Bibliography Mating Activity
1. Mating takes place in the water in a variety of postures. 2. Breeding herds consist of one cow in estrus accompanied by several bulls. An estrus female can be pursued for weeks by several males. The cow often twists and turns violently, apparently to escape her suitors. The bulls meanwhile attempt to remain adjacent to her, presumably competing with each other to become the first to mate with her. 3. While in estrous, cows may mate with several bulls. Cows do not form permanent bonds with bulls.
Captive Breeding
1. Manatees breed well in captivity, but it is not known how successful the offspring would be if released. Since space is limited at zoological facilities, emphasis is placed on the rehabilitation and reintroduction of injured manatees instead of breeding them.
2. Zoological institutions in Florida are on a voluntary breeding hold. Until the numerous problems are corrected in the manatee's natural environment, a breeding program will not be beneficial to them.
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Birth & Care of Young
Scientific Classification Manatee Birth & Care of Young Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Gestation Diet & Eating Habits 1. A Florida manatee's gestation is approximately 12 months. Reproduction
→ Birth & Care of Young
Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Manatees have a gestation of about 12 months and although Readers the calf may be weaned by the end of its first year, it remains close to its mother for up to two years. Bibliography Birth Seasons
1. Manatees in Florida and West Africa breed year-round. 2. In Florida, most calves seem to be born during the spring and summer. Most Amazonian manatees are born between February and May.
Frequency of Birth
1. A Florida manatee female produces a single calf about every two to five years, although females that have lost or aborted a calf have been known to give birth to another in just one year (Reynolds and Odell, 1991).
2. The birth of twins may occur, but is rare.
Calf at Birth
1. A West Indian manatee calf measures about 1.2 to 1.4 m (4-4.5 ft.) and weighs approximately 27 to 32 kg (60-70 lb.). 2. An Amazonian manatee calf measures about 80 cm (30 in.). 3. The calf can be born either head- or tail-first. 4. At birth, a calf has fetal folds in its skin which lasts for several weeks.
Care of Young
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Manatee calves swim to the surface after birth for their first breath of air.
2. Calves vocalize at or soon after birth. This auditory form of communication is an important part of the mother-calf bonding process. 3. The calf begins to nurse within a few hours after birth by suckling from teats under the pectoral flippers. Calves nurse under water.
Manatee calves begin nursing a few hours after birth. The mother's mammary gland is located under the front flippers.
4. Manatee milk contains mostly water with 20% solids, 7% protein, and 13% fat (lipids). 5. Calves begin nibbling on plants within a few weeks of birth. 6. Although it may be weaned by the end of its first year, the calf remains close to its mother for up to two years. It is dependent on its mother not only for nutrition, but also for learning about feeding and resting areas, travel routes, and warm water refuges.
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Longevity & Causes of Death
Scientific Classification Manatee Longevity & Causes of Death Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Longevity Diet & Eating Habits 1. Manatees probably live a maximum of about 50 to 60 years. Reproduction
Birth & Care of Young
→ Longevity & Causes of Death
Conservation & Research
Appendix
Books For Young Readers Manatees probably live a maximum of about 50 to 60 years. Bibliography Aging
1. A consequence of manatee tooth replacement is that scientists cannot use the teeth to age individual manatees, a procedure commonly used for many other species of marine mammals. Scientists instead use a method of aging manatees based on studying growth patterns that develop on ear bones.
Predators
1. Although predation has not been documented, scientists believe sharks, alligators, or crocodiles may occasionally attack West Indian manatees.
2. Crocodiles and sharks sometimes prey on West African manatees.
3. Jaguars, caimans, and sharks prey on Amazonian manatees.
Causes of Death
1. Natural causes.
Manatees are very susceptible to cold weather. It is not unusual for many to die during extremely cold weather. In 1996, at least 17 died due to cold related illnesses. During an exceptionally harsh winter in 1990, 46 manatees succumbed to the bad weather.
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Power plants create warm-water discharges that are sought by manatees.
Amazonian manatees become concentrated in confined areas when lakes dry up. They are susceptible to starvation and predation.
As in any animal population, a variety of diseases and parasites can be responsible for manatee deaths.
In early 1996, about 150 manatees died in southwest Florida. Scientists determined the mass mortality was caused by a red tide organism called Gymnodinium breve which produces toxins. The manatees died after ingesting or breathing in the toxins which attacked their organs (Luoma, 1996). 2. Human-related causes.
Watercraft accidents.
More than 770,000 boats were registered in Florida for the 1995-96 season.
Manatees are sometimes difficult for boaters to see in the water.
Due to their dark color and because they are slow swimmers, manatees are difficult to see in the water. At least 20% to 22% of manatee deaths in Florida occur from watercraft accidents yearly. Collisions with boats and barges is the largest human-related factor causing manatee deaths in Florida. (U. S. Fish and Wildlife Service, 1995).
Although the engine propellers are dangerous, collisions with boats cause the most watercraft related deaths. In 1995, 12 manatees expired from propeller injuries while 25 died from impact wounds. Collisions with boats cause life-threatening internal injuries that are often hard to locate and treat.
Only 5% of 400 manatees surveyed had head injuries from boating accidents while more than 70% had wounds on their upper backs. This suggests that manatees try to dive away from boats but cannot escape in time to avoid injuries (Bloch, 1993).
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Manatees become entangled in fishing and crab trap lines, sometime resulting in serious wounds.
This manatee's flipper became entangled in a crab trap and will require medical treatment.
Flood gates and navigation locks.
As manatees swim upstream, they may encounter flood gates and navigation locks. When flood gates are left partially open, manatees sometimes swim through them. They may become trapped in the water current from the upstream side and drown. The remote-controlled flood gates have also crushed manatees.
Entrapment in flood control gates and navigation locks regularly kill manatees and is the second leading human factor for manatee deaths. A record 16 manatees died from these devices in 1994. From 1976 to 2000, 166 manatees were confirmed dead from flood gates and navigational locks in the state of Florida.
To help the problem, engineers are installing pressure-sensitive mechanisms on flood gates known to cause the most manatee deaths. The cost of each sensor is about $50,000 (U. S. Fish and Wildlife Service, 1995).
Poaching and vandalism.
In spite of the fact that manatees are legally protected, poachers and vandals are also responsible for manatee deaths. In some areas manatees are hunted for food. Others are victims of harassment.
Accidental entanglement and pollution.
Florida manatees have been found with fishing lines or crab trap lines wrapped around them. These materials can wrap tightly around the manatee's flippers, causing serious infections, amputations, or death.
In a survey of 439 manatee carcasses, 14.4% had debris in their stomach.
Habitat destruction.
Since the 1950s destruction of the natural habitats of many coastal animals is accelerating at an alarming rate. Much of the suitable manatee habitat in Florida (seagrass beds, salt marshes, and mangrove areas) has been destroyed.
The human population in Florida increases by nearly 1,000 people daily.
About 250,000 acres of forests are lost every year in Florida and roughly one-fourth of the state remains semi-natural. http://seaworld.org/en/animal-info/animal-infobooks/manatee/longevity-and-causes-of-death/ 3/4 1/10/2015 seaworld.org/en/animal-info/animal-infobooks/manatee/longevity-and-causes-of-death/ 3. Death increases.
All total, a record 415 manatees died in 1996. Even when the 150 manatees that died from the red tide outbreak were subtracted, it was still the worst year for manatee deaths ever recorded in Florida. The total mortality rate for Florida manatees has risen an average of 5.3% every year since 1976.
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PARKS KIDS SHOP ANIMALS CARE LANGUAGE
Conservation & Research
Scientific Classification Manatee Conservation & Research Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Endangered Species Diet & Eating Habits 1. All four species of sirenians are endangered or threatened.
Reproduction 2. The Florida manatee is one of the most endangered marine mammals in the United States. Birth & Care of Young
Longevity & Causes of Death
→ Conservation & Research
Appendix
Books For Young Readers
Bibliography Manatees are endangered in the United States.
Legal Protection
1. All species of sirenians are protected to some extent by national or local acts in every country they inhabit. 2. Federal and state laws have been passed that protect Florida manatees.
Federal laws prohibit hunting, capturing, killing, or harassing these animals. These laws include the Marine Mammal Protection Act of 1972 and the Endangered Species Act of 1973. Penalties for breaking these federal laws could include a year in prison and a fine up to $20,000.
The Florida Manatee Sanctuary Act of 1978 is state legislation that allows the establishment of manatee sanctuaries in Florida.
3. West African manatees are protected under Class A of the African Convention of Nature and Natural Resources, signed by 38 African countries.
4. Amazonian manatee hunting has been prohibited since 1973.
5. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international treaty developed in 1973 to regulate trade of wildlife items. All species of sirenians are protected by this treaty.
Marine Zoological Parks
1. Marine zoological parks such as SeaWorld Florida and SeaWorld California help conserve manatees. SeaWorld is authorized to rescue and rehabilitate ill, injured, or orphaned manatees.
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SeaWorld is authorized to rescue and rehabilitate ill, injured, and orphaned manatees.
2. The first priority of the manatee rescue and rehabilitation program is to return healthy manatees to their natural habitat. SeaWorld Florida has successfully rescued and released more than 80 manatees as of December 2000. SeaWorld Florida rescued 13 manatees in 2000 and released six.
The first priority of the manatee rescue and rehabilitation program is to return healthy manatees to their natural habitat.
3. In the controlled environment of a marine zoological park, scientists can study aspects of manatee biology that are difficult or impossible to study in the wild.
Having manatees at marine zoological parks provide the opportunity for the public to learn about these rare animals.
Having manatees at marine zoological parks provides the opportunity for the public to learn about these rare animals.
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PARKS KIDS SHOP ANIMALS CARE LANGUAGE
Appendix
Scientific Classification Manatee Appendix Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Table: Florida Manatee Census Counts Diet & Eating Habits
Reproduction DATE OF SURVEY TOTAL COUNT Birth & Care of Young Jan. 23-24, 1991 1,267 Longevity & Causes of Feb. 17-18, 1991 1,465 Death Jan. 17-18, 1992 1,856 Conservation & Jan. 21-22, 1995 1,443 Research Feb. 6-7, 1995 1,822
→ Appendix Jan. 9-10, 1996 2,274 Feb. 18-19, 1996 2,639 Books For Young Readers Jan. 19-20, 1997 2,229 Feb. 13, 1997 1,709 Bibliography Jan. 29-30, 1998 2,022 Jan. 6, 1999 1,873 Feb. 23, 1999 2,034 March 6, 1999 2,353 Jan. 16, 2000 1,629 Jan. 27, 2000 2,222 Jan. 2001 3,276 March 2002 1,796
Table: Manatee Deaths By Year/Category
YEAR WTRCRFT LCK/GT OTHER NAT UNKNWN PERINTL* TOTAL 1976 10 3 0 1 32 16 (1) 62 1977 13 6 5 1 79 11 (1) 115 1978 21 9 1 3 40 10 84 1979 22 8 8 4 24 12 (3) 78 1980 15 8 2 6 19 15 (1) 65 1981 23 2 4 9 65 14 (1) 117 1982 19 3 2 40 37 16 (1) 117 1983 15 7 5 6 30 18 81 1984 33 3 1 24 41 28 (1) 130 1985 35 3 3 20 39 23 123
1986 31 3 1 13 47 30 (2) 125 1987 37 5 3 15 23 34 (3) 117 http://seaworld.org/en/animal-info/animal-infobooks/manatee/appendix/ 1/2 1/10/2015 seaworld.org/en/animal-info/animal-infobooks/manatee/appendix/ 1988 43 7 3 22 25 34 (1) 134 1989 50 3 4 32 45 42 (2) 176 1990 49 3 4 71 41 46 214 1991 52 9 6 15 39 54 (1) 175 1992 38 5 6 21 49 48 167 1993 34 6 7 24 36 40 (1) 147 1994 50 16 5 37 40 46 194 1995 43 8 5 35 55 57 203 1996 59 10 1 118 164 64 (1) 416 1997 52 8 8 46 67 65 (4) 246 1998 66 9 6 23 85 54 (1) 243 1999 83 15 7 43 69 57 (1) 274 2000 78 7 9 51 70 58 273 2001 81 1 7 33 108 33 325
TOTAL 1052 167 113 713 1369 925 (26) 4401
Manatee Mortality Database
The manatee mortality database is now available on the web site of the Florida Fish & Wildlife Conservation Commission's Florida Marine Research Institute (FMRI). In addition to the monthly mortality tables already available on the web site, the new database enables the user to search for manatee mortality information by county, cause of death and date from 1974 through 2001. Two report formats are available: A 'summary' report which lists the search results in a numbers-only table, and an 'individual' report which provides more detailed information such as sex, size, region and cause of death. You can find the new manatee mortality search on the FMRI web site at http://www.floridamarine.org/manatees/.
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Books for Young Readers
Scientific Classification Manatee Books For Young Readers Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior Book List Diet & Eating Habits Amazing Animals of the Sea. Washington, D.C.: National Geographic Society, 1981. Reproduction Crump, Donald, ed. National Geographic Book of Mammals. Vol. II. Washington, D.C.: National Geographic Birth & Care of Young Society, 1981. Goff Clark, Margaret. The Vanishing Manatee. New York: Cobblehill Books, 1990. Longevity & Causes of Death Gordon, Esther and Bernard. Once There Was a Giant Sea Cow. New York: Henry Z. Walck, Inc. 1977. Conservation & Research Kuzmier, Kerrie and Jennifer McCann. Manatees and Dugongs. Washington, D.C.: Center for Marine Conservation, 1990. Appendix Parham, Donna. To the Rescue! San Diego: Seaworld Education Department Publications, 2001.
→ Books For Young Sibbald, Jean H. The Manatee. Minneapolis, Minnesota: Dillon Press, Inc., 1990. Readers
Bibliography Unterbrink, Mary. Manatees Gentle Giants in Peril. St. Petersburg, Florida: Great Outdoors Publishing Co., Inc., 1984. Wlodarski, Loran. The Story of Manatees. Siren’s Song. Orlando: SeaWorld Education Department Publications, 2003. Wlodarski, Loran. Wild Careers! Working With Animals. Orlando: SeaWorld Education Department Publications, 2003.
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PARKS KIDS SHOP ANIMALS CARE LANGUAGE
Bibliography
Scientific Classification Manatee Bibliography Habitat & Distribution
Physical Characteristics
Senses
Adaptations
Communication
Behavior References Diet & Eating Habits Arseniev, V.A. Atlas of Marine Mammals. Neptune City: T. F. H. Publishing, Inc., 1986. Reproduction Blashfield, Jean F. Awesome Almanac Florida. New York: B&B Publishing, 1994. Birth & Care of Young Blank, Joan. Key Biscayne. Tampa: Pineapple Press, 1996. Longevity & Causes of Death Bloch, Nini. "The Last Mermaids." Earthwatch 12(7), Nov.-Dec. 1993, pp. 16-23. Conservation & Research Chapman, J. A. and G. A. Feldhamer. Wild Mammals of North America. Baltimore: The Johns Hopkins University Press of Florida, 1993. Appendix Dietz, Tim. The Call of the Siren. Golden: Fulcrum Publishing, 1992.
Books For Young Griebel, Ulrike and Axel Schmid. "Color Vision in the Manatee." Vision 13(17), 1996, pp. 2747-2757. Readers
Functional Anatomy of Marine Mammals → Bibliography Harrison, R. J. . New York: Academic Press, 1974.
Luoma, Jon R. "What's Killing the Manatees?" Audubon 98(4), July-August 1996, pp. 18-22.
Nowak, R. M. and J. L. Paradiso. Walker's Mammals of the World. Baltimore: The Johns Hopkins University Press, 1999. O'Shea, Thomas J. "Manatees." Scientific American 271(1), July 1994, pp. 66-72.
O'Shea, Thomas J., B. B. Ackerman and H. F. Percival. Population Biology of the Florida Manatee. Washington D.C.: Publishing Unit, U.S. Fish and Wildlife Service, 1995. Reynolds, John E. III and Daniel K. Odell. Manatees and Dugongs. New York: Facts On File, Inc., 1991.
Mammals of the Sea. Rome: Food and Agriculture Organization of the United Nations, Vol. II, 1979.
Ridgeway, Sam H. and Sir Richard Harrison. Handbook of Marine Mammals. Orlando: Acedemic Press, Inc., 1985. Savage, R. J. G., Daryl P. Domning and J. G. M. Thewissen. "Fossil Sirenia of the West Atlantic and Caribbean Region." Journal of Vertebrate Paleontology 14(3), September 1994. Stejneger, Leonard. Georg Wilhelm Steller. Cambridge: Cambridge Press, 1936.
U.S. Fish and Wildlife Service. Florida Manatee Recovery Plan Third Revision. Atlanta: U.S. Fish and Wildlife Service Press, 2000. Van Meter, Victoria Brook. The West Indian Manatee in Florida. Florida Power and Light Company Publishings, 1989.
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