Stellers Sea Cow (Hydrodamalis Gigas) - Animals - A-Z Animals Five groups that classify all living things Animalia A group of animals within the animal kingdom Chordata A group of animals within a pylum Mammalia A group of animals within a class Sirenia A group of animals within an order Dugongidae A group of animals within a family Hydrodamalis Comprised of the genus followed by the species Hydrodamalis Gigas The animal group that the species belongs to Mammal What kind of foods the animal eats Herbivore How long (L) or tall (H) the animal is 8m - 9m (26ft - 30ft) The measurement of how heavy the animal is 8000kg (8.8tons) How long the animal lives for 50 - 80 years Whether the animal is solitary or sociable Herd The likelihood of the animal becoming extinct Extinct When the entire species has disappeared from Earth 1758 AD The colour of the animal's coat or markings Grey, Brown, Black The protective layer of the animal Smooth The specific area where the animal lives Arctic Tundra The average number of babies born at once 1 Other

 animals that hunt and eat the animal Large sharks and humans Characteristics unique to the animal Enormous body size and toothless mouths Stellers Sea Cow Location Stellers Sea Cow The Steller's sea cow was a large marine mammal that was found in abundance in the North Pacific.

These enormous animals were closely related to the dugong and the manatee still found grazing in the oceans today, but were of considerable size at between eight and nine meters in length. The Steller's sea cow was first discovered in 1741 by explorers that ventured into parts of the Arctic Circle. When they were first recorded, the Steller's sea cow was said to be living in abundance in the North Pacific, however in less than 20 years of human contact, the Steller's sea cow had disappeared from the ocean completely. Steller's sea cows were large herbivores that had a seal-like appearance with a tail which resembled that of a whale. The Steller's sea cow was named after George Steller who discovered the animal and who described it: "The animal never comes out on shore, but always lives in the water. Its skin is black and thick, like the bark of an old oak, its head in proportion to the body is small, it has no teeth, but only two flat white bones one above, the other below".

The Steller's sea cow was said to be a tame animal that spend most of it's time concerning itself with munching on kelp, which is possibly what made it so vulnerable later on. However, the Steller's sea cow was also said to be unable to submerge it's enormous body fully underwater making it an easy spot for human hunters. The Steller's sea cow was a herbivorous animal that would have had a very similar diet to the dugong and manatees still extant today. This toothless animal would have spent the majority of its time grazing on kelp, sea weed and other aquatic grasses that grow in the shallows of the oceans. Before being discovered by humans , the Steller's sea cow would have had very few predators within it's watery world. Large shark species would have been the only predators able to tackle such an enormous meal, but non were more successful at hunting this enormous sea cow than humans who wiped out the entire species in just 17 years. The Steller's sea cow would have mated and given birth to it's calf in the water (as these marine mammals do not go onto the land).

In much the same way as it's smaller cousins, the female Steller's sea cow would have given birth to a single calf after a gestation period that probably lasted well over a year. The sea cow calf would of remained with it's mother until it was strong enough to become independent. Sadly, these remarkable giants of the sea, where wiped out by human hunters almost instantly after having been discovered by explorers. Today, it's smaller cousins are also under serious threat in their native habitats from over-hunting and increasing levels of pollution in the water. Share This Article Manatees and Sea Cows Entertainment Magazine : Science: Manatee and Sea Cows The Florida Manatee By Scott Sosssong The Florida manatee, Florida’s state marine mammal, is a large aquatic relative of the elephant. They are grayish brown in color and have thick, wrinkled skin on which there is often a growth of algae. Their front flippers help them steer or sometimes crawl through shallow water. They also have powerful flat tails that help propel them through the water. Despite their small eyes and lack of outer ears, manatees are thought to see and hear quite well.

Manatees are marine mammals of the order Sirenia, also known as "sea-cows". These beautiful animals can be found in shallow waters, bays, canals and coastal areas. The manatee has a streamlined body, with two flippers and one paddle-shaped tail. Their true color is gray, although it may appear brownish gray. Adult manatees can grow up to 12 feet in length and weigh around 1,800 pounds. Females are generally larger than males. Although manatees have few natural predators, they are vulnerable to extinction and they are also called sea cows because the are a cousin from an elephant. The Manatee: Trichechus manatus latirostrus Length 10-12 feet Mating Season No specific period Gestation About 1 year Number of offspring 1 calf Calves are born weighing between 60 and 70 pounds and measuring about 3-4 feet. They nurse underwater. Watch video of the Mantee Threats to the Manatee Destruction and degradation of their coastal and freshwater habitat. The leading known cause of death is by boat strikes; propellers and hulls inflict serious or mortal wounds.

Most manatees have a pattern of scars on their backs or tails after surviving collisions with boats. Scientists use these patterns to identify individuals. Manatees are also vulnerable to cold water. They have been found crushed or drowned in flood-control gates and suffer harm from exposure to toxic red tide. In addition, a large number of manatees die from unknown causes each year. Legal Status/Protection Federally listed as Endangered and state listed as Endangered. *Endangered Species Act; **Marine Mammal Protection Act; Florida Endangered and Threatened Species Act; Florida Administrative Code; Florida Marine Sanctuary Act; ***CITES Appendix 1. * The Endangered Species Act requires the US federal government to identify species threatened with extinction, identify habitat they need to survive, and help protect both. In doing so, the Act works to ensure the basic health of our natural ecosystems and protect the legacy of conservation we leave to our children and grandchildren. ** The Marine Mammal Protection Act prohibits, with certain exceptions, the take of marine mammals in U.S. waters and by U.S. citizens on the high seas, and the importation of marine mammals and marine mammal products into the U.S.

*** Convention on International Trade in Endangered Species of Wild Fauna and Flora, an international treaty with 172 member countries. Appendix I species cannot be traded commercially. Appendix II species can be traded commercially only if it does not harm their survival. Manteea also called Sea Cows Manatees (family Trichechidae, genus Trichechus) are large, fully aquatic marine mammals sometimes known as sea cows. The name manati comes from the Taino, a pre-Columbian people of the Caribbean, meaning 'breast'. They contain three of the four living species in the order Sirenia, the other being the dugong, which is native to the Eastern Hemisphere. The Sirenia is thought to have evolved from four-legged land mammals over 60 million years ago, with the closest living relatives being the Proboscidea (elephants) and Hyracoidea (hyraxes). Manatees are mainly herbivores, spending most of their time grazing in shallow waters and at depths of 1-2 meters (3-7 ft). Much of the knowledge about manatees is based upon research done in Florida and cannot necessarily be attributed to all types of manatees.

Generally, manatees have a mean mass of 400-550 kg (900-1200 lb), and mean length of 2.8-3.0 m (9-10 ft), with maximums of 3.6 meters and 1,775 kg seen (the females tend to be larger and heavier). When born, baby manatees have an average mass of 30 kg. On average, most manatees swim at about 5 km/h to 8 km/h (1.4 m/s to 2.2 m/s; 3 to 5 miles per hour). However, they have been known to swim up to 30 km/h (8 m/s; 20 miles per hour) in short bursts. Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea and the Gulf of Mexico (T. manatus, West Indian Manatee), the Amazon Basin (T. inunguis, Amazonian Manatee), and West Africa (T. senegalensis, West African Manatee). A fourth species, the Dwarf Manatee (T.

bernhardi) was recently proposed for a population found in the Brazilian Amazon, although some have questioned its validity, instead believing it is an immature Amazonian Manatee. Florida is usually the northernmost range of the West Indian Manatee as their low metabolic rate makes cold weather endurance difficult. They may on occasion stray up the mid-Atlantic coast in summer. Half a manatee's day is spent sleeping in the water, surfacing for air regularly at intervals no greater than 20 minutes. Florida Manatees (T. m. latirostris) have been known to live up to 60 years, and they can move freely between different salinity extremes; however, Amazonian Manatees (T. inunguis) never venture out into salt water. They have a large flexible prehensile upper lip that acts in many ways like a shortened trunk, somewhat similar to an elephant's. They use the lip to gather food and eat, as well as using it for social interactions and communications. Their small, widely spaced eyes have eyelids that close in a circular manner. Manatees are also believed to have the ability to see in color.

They emit a wide range of sounds used in communication, especially between cows and their calves, yet also between adults to maintain contact and during sexual and play behaviors. They may use taste and smell, in addition to sight, sound, and touch, to communicate. Manatees are capable of understanding discrimination tasks, and show signs of complex associated learning and advanced long term memory. They demonstrate complex discrimination and task-learning similar to dolphins and pinnipeds in acoustic and visual studies. Manatees typically breed only once every other year, since gestation lasts about 12 months, and it takes a further 12 to 18 months to wean the calf. Only a single calf is born at a time and aside from mothers with their young or males following a receptive female, manatees are generally solitary creatures. Quick Guide to Manatees DESCRIPTION: Large, seal-like body that tapers to a powerful flat tail. Two agile forelimbs with three to four toenails on each, which act like arms to help the manatee maneuver in shallow water, grasp and move food toward their mouths, and act like flippers during swimming. Thick and wrinkled skin with a rough texture - a bit jiggly under the neck and arms.

Their skin reacts to touch, as their bodies are very muscular - contracting and changing shape slightly when scratched or tickled. Powerful upper lips which articulate to help maneuver food or dig through sediment. SIZE : Average 9 to 10 feet long, weighing around 1,000 lbs. Can grow as large as 13 feet and weigh more than 3,000 lbs. Calves are born weighing about 40 lbs, gaining about 700 lbs. during their first year. BEHAVIOR : Gentle and generally slow-moving. Most of the time is spent eating vegetation (100-150 lbs. per day), resting and traveling. On average manatees can travel about 40 to 50 miles a day, sometimes farther. Chessie, the famed manatee rescued from the cold waters of the Chesapeake Bay and returned to Florida, was tagged with a locating device which showed he traveled as far as Rhode Island during hot summer months. SIGHT : Some people believe Manatees are near sighted, or may have limited depth perception. It is believed that they can differentiate between colors.

It is unclear how manatees navigate in pitch black or murky waters - when their eyesight would be of no use. They do have sparse bodyhair over their bodies, and thick whiskers on their faces. It is not clear if this aids in navigation. One expert is convinced, however, that they know exactly where swimmers are, even in blackout conditions. HEARING : Manatees can hear very well despite the absence of external ear lobes. They are not believed to have the capabilities of echolocation. COMMUNICATIONS : 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. No air is released from the manatee when these sounds are made, and it is not clear where the sounds are being produced or if they serve any other purpose. BREATHING : Manatees are mammals and breath air through their noses at the surface - with nostrils which close tightly when submerged. They breath every few minutes when active or swimming, and every 10 to 15 minutes when resting. They are capable of exchanging 98% of their lungs capacity in one breath.

Their lungs are very large, and are also used for buoyancy control. The rushing sound of a deep exhale and breath sound much like a snorkeler. This sound, and the associated "footprint" left by the manatees tail and body at the surface are clues which reveal the presence of manatees in the area. HABITAT AND FOOD : Manatees are found in coastal waterways, estuaries, salt water bays, rivers and canals, particularly where seagrass beds are located. Manatees are completely herbivorous and can eat 10-15% of their bodyweight daily. In captivity they are fed lettuce and other greens, and given elephant vitamins. REPRODUCTION : Females mature around 5 to 9 years of age, and males not until 6 to 9 years of age. It is believed that one calf is born every 2 to 5 years. Twins are rare in the wild. Gestation period is around 13 months. Newborns weigh approximately 40 pounds at birth and stay with them other for several years.

Sea cow - definition of sea cow by The Free Dictionary Sea cow - definition of sea cow by The Free Dictionary Related to sea cow: Sirenia , Mammals sea cow n. Any of several large herbivorous marine mammals of the order Sirenia, having a paddlelike tail, forelimbs shaped like flippers, and no hind limbs, and including the manatee, the dugong, and Steller's sea cow (Hydrodamalis stelleri) of the northern Pacific, which became extinct in the late 1700s. Also called sirenian. sea cow 1. (Animals) any sirenian mammal, such as a dugong or manatee 2. (Animals) an archaic name for walrus sea′ cow` Noun 1.

sea cow - any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs aquatic mammal - whales and dolphins; manatees and dugongs; walruses; seals order Sirenia , Sirenia - an animal order including: manatees; dugongs; Steller's sea cow manatee , Trichechus manatus - sirenian mammal of tropical coastal waters of America; the flat tail is rounded dugong , Dugong dugon - sirenian tusked mammal found from eastern Africa to Australia; the flat tail is bilobate Hydrodamalis gigas , Steller's sea cow - extinct large sirenian mammal formerly found near the Asiatic coast of the Bering Sea Translations 海牛 Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: sea References in classic literature ?

He was going to find Sea Cow, if there was such a person in the sea, and he was going to find a quiet island with good firm beaches for seals to live on, where men could not get at them. Then he remembered in a flash what the Burgomaster gull had screamed to him when he was a little yearling at Walrus Islet, and he tumbled backward in the water, for he knew that he had found Sea Cow at last. But the sea cows did not answer because Sea Cow cannot talk. Then the Sea Cow began to travel northward very slowly, stopping to hold absurd bowing councils from time to time, and Kotick followed them, saying to himself, "People who are such idiots as these are would have been killed long ago if they hadn't found out some safe island. Kotick followed, and the pace astonished him, for he never dreamed that Sea Cow was anything of a swimmer. No one but a sea cow or a seal would have dreamed of there being such a place, and when he looked back at the cliffs even Kotick could hardly believe that he had been under them.

The sea cows had separated and were browsing lazily along the edges of the finest beaches that Kotick had ever seen. Manatees: Facts, Information & Pictures A manatee munching down on some sargassum. Credit: USGS - Sirenia Project The manatee is a large marine mammal with an egg-shaped head, flippers and a flat tail. Manatees are also known as sea cows. This name is apt, due to their large stature; slow, lolling nature; and propensity to be eaten by other animals. However, despite the name, they are more closely related to elephants. Though they may seem like cumbersome creatures, manatees can swim quickly and gracefully. Manatees range in size from 8 to 13 feet (2.4 to 4 meters) and can weigh 440 to 1,300 lbs. (200 to 590 kilograms). They have large, strong tails that power their swimming. Manatees usually swim about 5 mph (8 km/h), but they can swim up to 15 mph (24 km/h) in short bursts when they feel a need for speed, according to National Geographic .

Habitat There are three species of manatee: the Amazonian manatee (Trichechus inunguis); the West Indian manatee, or the American manatee (Trichechus manatus); and the African manatee (Trichechus senegalensis). Their names indicate the regions in which they live. Typically, manatees stay in rivers, seas and oceans along the coast of several countries. The African manatee lives along the coast and in the rivers of western Africa. The Amazon manatee lives in the Amazon River's drainage, from the headwaters in Colombia, Peru and Ecuador to the mouth of the Amazon in Brazil. Their range is estimated to be around 2.7 million square miles (7 million square kilometers), according to the International Union for Conservation of Nature (IUCN). The West Indian manatee lives in the southern and eastern United States, although a few "vagrants" have been known to reach the Bahamas, according to the IUCN. Habits Manatees often swim alone or in pairs. They are not territorial, so they have no need for a leader or followers.

When manatees are seen in a group, it is either a mating herd or an informal meeting of the species simply sharing a warm area that has a large food supply. A group of manatees is called an aggregation. An aggregation usually never grows larger than about six individuals, according to the Save the Manatee Club. Diet Manatees are herbivores. At sea, they tend to prefer sea grasses. When they live in rivers, they consume freshwater vegetation. Manatees also eat algae. According to National Geographic, a manatee can eat a tenth of its own weight in 24 hours. That can equal up to 130 lbs. (59 kg). Offspring During mating, a female manatee, which is called a cow, will be followed around by a dozen or more males, which are called bulls. The group of bulls is called a mating herd. Once the male has mated, though, he takes no part in the raising of the young. A female manatee is pregnant for about 12 months , according to Save the Manatee Club. The calf, or baby manatee, is born underwater.

The mother helps the calf get to the water's surface for air, and within the first hour of life, the calf will be able to swim on its own. In five years, the young manatee will be sexually mature and ready to have its own young. Manatees usually live about 40 years. Classification/taxonomy According to the Integrated Taxonomic Information System (ITIS), the manatee's full classification is: Kingdom: Animalia Family: Trichechidae Genus:Trichechus Species: Trichechus inunguis (Amazonian manatee, South American manatee), Trichechus manatus (West Indian manatee, American manatee, Caribbean manatee), Trichechus senegalensis (African manatee, West African manatee) Subspecies: Trichechus manatus latirostris (Florida manatee), Trichechus manatus manatus (Antillean manatee) Conservation status The IUCN's Red List of Threatened Species lists all manatees as vulnerable or endangered and facing a high risk of extinction. Populations are expected to decline by as much as 30 percent over the next 20 years.

Numbers are hard to come by, especially for the secretive Amazonian manatee ; the IUCN says the estimate of 10,000 manatees should be regarded with caution because the numbers are supported by little empirical data. Similarly, the exact number of African manatees is unknown, but the IUCN estimates there are fewer than 10,000 manatees in West Africa. The Florida manatee and the Antillean manatee are listed as endangered because the number of mature individuals is also estimated to be fewer than 2,500 for each subspecies, and the populations are expected to decline by more than 20 percent over the next two generations, or about 40 years. One reason for these statuses is that manatees reproduce very slowly — the time between generations is about 20 years. In addition, fishermen trawling with nets in the Amazon and West Africa pose a grave threat to these slow-moving mammals. Also, in West Africa, manatees are hunted for their meat. Habitat loss from waterfront development also impacts their survival. Manatees are also vulnerable to collisions with speedboats . Manatees are also a federally listed endangered species in the United States.

Other facts Manatees are thought to have evolved from four-legged land mammals more than 60 million years ago. Except for the Amazonian manatee, their paddlelike flippers have vestigial toenails — a remnant of the claws they had when they lived on land. The Amazon species name "inunguis" is Latin for "without nails." The name manatee comes from the Taíno (a pre-Columbian people of the Caribbean) word manatí, meaning "breast." Manatees' eyes are small, but their eyesight is good. They have a special membrane that can be drawn across the eyeball for protection. Their hearing is good too , despite not having outer ear structures, because manatees have large inner ear bones. Manatees' only teeth are called marching molars. Throughout a manatee's life, the molars are constantly replaced — an adaption to their diet of abrasive vegetation. Manatees have only six neck vertebrae. Most other mammals, including giraffes, have seven. As a result, manatees cannot turn their heads sideways, and must turn their whole body around to look behind them.

Algae, photosynthetic organisms, often grow on manatees' skin. Manatees never go on land. Manatees don't always need to breathe. As they swim, they poke their nose up above the water's surface to catch a few breaths every few minutes. If they are simply resting, they can stay under the water for 15 minutes without taking a breath, according to National Geographic. An animal that is similar to the manatee is the dugong (Dugong dugon). Dugongs are also in the order Sirenia, but they are in a different family, Dugongidae. These manatee cousins are found in the Indian and Pacific oceans. They have a notch in their tails, as well as tusks. Manatees and dugongs may have inspired mermaid legends . In ancient mythology, sirens were monsters or sea nymphs who sang mesmerizing songs that lured sailors to steer their ships onto treacherous rocks. After a long sea voyage, sailors may have thought they were seeing sirens, or mermaids, when they were probably seeing manatees or dugongs.

Additional resources The USGS Sirenia Project conducts long-term, detailed studies of the West Indian manatee. The Florida Manatee Program can tell you where to see manatees and provides a boater's guide to avoid collisions. At Save the Manatee Club , you can "adopt" a real manatee.

Donations help fund manatee conservation." Editor's Recommendations Dugong (Dugong Dugon) - Animals - A-Z Animals Five groups that classify all living things Animalia A group of animals within the animal kingdom Chordata A group of animals within a pylum Mammalia A group of animals within a class Sirenia A group of animals within an order Dugongidae A group of animals within a family Dugong Comprised of the genus followed by the species Dugong Dugon The animal group that the species belongs to Mammal What kind of foods the animal eats Herbivore How long (L) or tall (H) the animal is 2.7m - 3m (8.9ft - 9.8ft) The measurement of how heavy the animal is 150kg - 400kg (330lbs - 880lbs) The fastest recorded speed of the animal 22km/h (13mph) How long the animal lives for 50 - 70 years Whether the animal is solitary or sociable Solitary The likelihood of the animal becoming extinct Threatened The colour of the animal's coat or markings Brown, Grey The

 protective layer of the animal Leather The specific area where the animal lives Warmer tropical waters and sea grass forests The average number of babies born at once 1 Other animals that hunt and eat the animal Human, Sharks, Crocodile Characteristics unique to the animal Large body size and forked tail Dugong Location Dugong The dugong is a large marine mammal found in the warm waters surrounding Indonesia and Australia .

Although the dugong can be found widely throughout the Indo-Pacific tropics, the highest population of the dugong is concentrated around northern Australia. Although the dugong looks extremely similar to a manatee , the two are different species . The dugong and the manatee are very closely related and can look almost identical until you look at their tail. The tail of the dugong is typically forked like the tail of a shark, where the tail of the manatee is broad and flat, and slightly more flipper looking than fin looking. Dugongs are smaller than manatees with the average adult dugong reaching lengths of around 3 meters and weigh nearly 400 kg, which is about the same as a large cow . The front flippers of the dugong can be as much as half a meter in length. It is thought the legends of mermaids may have originated when sailors from a distance glimpsed dugongs swimming in the water, and mistook them for half-human half-fish creatures. These mermaid legends are also said to be true of the dugongs larger cousin, the manatee.

Dugongs inhabit the warm shallow waters, and despite their large size , dugongs are strictly herbivorous animals and have been referred to as the cows of the sea. Dugongs graze on sea grasses and aquatic plants that grow in abundance in the tropical shallows. Dugongs eat large amounts of sea plants and often leave feeding trails behind of bare sand and uprooted sea grass. Female dugongs give birth to just one calf about once every five years. The baby dugong is born underwater in the warm shallows, where the baby dugong is immediately able to swim to the surface in order to take its first breath. When the baby dugong is born, the dugong calf is about a meter in length and weighs about 20 kg. The dugong calf will stay close to its mother until the baby dugong is about 2 years old. Dugong populations are constantly decreasing, with many dugongs being accidental victims in large commercial fishing. Dugongs are now considered to be vulnerable animals but the dugong will commonly get older than 70 years of age. Dugong calves will not reach their full size until they are about 15 years old.

Share This Article Lumbering Sea Cows Were Once Plentiful and Diverse Lumbering Sea Cows Were Once Plentiful and Diverse By Jennifer Welsh | March 8, 2012 06:05pm ET MORE This dugong is one of four seacow, or Sirenians, species in the world. They all live in different coastal areas of the ocean. Credit: Julien Willem Today's sea cows are lonely: They share their habitat only with others of their species. This wasn't always the case, new research suggests. In the past multiple species of sea cow lived together in harmony. Sea cows, also known as Sirenians, are defined by four species, the best known in the United States being our Florida resident, the manatee. There are two other species of manatee in the Atlantic Ocean, as well as the dugong, from the Indo-Pacific. Searching for sea cows The researchers found multiple examples of Sirenians in the same fossil bed at the same depth — evidence the two species would have lived in the same area at the same time.

"We were culling through the fossil record of sea cows and finding those few cases we could be certain that these things lived together," study researcher Nicholas Pyenson, a curator of fossil marine mammals at the Smithsonian Institution, told LiveScience. "In some cases we found the fossils literally on top of each other." Three sets of sea cows lived in three different times and locations: the late Oligocene (23 million to 28 million years ago) in Florida, the early Miocene (16 million to 23 million years ago) in India and the early Pliocene (3 million to 5 million years ago) in Mexico. Credit: Carl Buell Before modern times, up to three species of these big herbivores (they eat mainly sea grasses) could be found together in the same area. This suggests that the environment and food sources for ancient sea cows were different in the past, but researchers weren't sure how.

They analyzed the fossils of species seen living together in the past during three different time periods and locations: the late Oligocene (23 million to 28 million years ago) in Florida, the early Miocene (16 million to 23 million years ago) in India and the early Pliocene (3 million to 5 million years ago) in Mexico. Different diets Whether one or more species can survive in the same habitats isn't about aggression against each other, but the two species sharing the limited resources available to them. Any two species that eat the same thing in the same place will be competing, even if the two never face off. Both will do better if they eat slightly different foods, so they aren't in direct competition. They were looking for skeletal differences to indicate if that was how multiple species of sea cow were able to live in harmony. Based on their skull and jaw shape, species living in the same areas did seem to specialize in different types of sea grass , so they probably weren't competing for food.

"We were able to look at the shape of their snouts, their teeth, their body size — we looked at those kinds of measures, and that shows us that these animals had strong ecological differences and were likely feeding on different kinds of sea grasses," Pyenson said. "Some would eat different sized roots; some would eat different sized stems." They were able to specialize in one type of food because habitats were once dominated by several species of sea grass, whereas today sea cow habitats are limited to one or two, which therefore limits the number of sea cow species living there. This loss of species diversity is seen in other areas of the fossil record, too, Pyenson said. The study was published online Feb. 9 in the journal PLoS ONE. You can follow LiveScience staff writer Jennifer Welsh on Twitter @ microbelover . Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook . Editor's Recommendations Manatees, Manatee Pictures, Manatee Facts - National Geographic Size relative to a 6-ft (2-m) man Please add a "relative" entry to your dictionary. Manatees are sometimes called sea cows, and their languid pace lends merit to the comparison.

However, despite their massive bulk, they are graceful swimmers in coastal waters and rivers. Powering themselves with their strong tails, manatees typically glide along at 5 miles (8 kilometers) an hour but can swim 15 miles (24 kilometers) an hour in short bursts. Manatees are usually seen alone, in pairs, or in small groups of a half dozen or fewer animals. From above the water's surface, the animal's nose and nostrils are often the only thing visible. Manatees never leave the water but, like all marine mammals, they must breathe air at the surface. A resting manatee can remain submerged for up to 15 minutes, but while swimming, it must surface every three or four minutes. There are three species of manatee, distinguished primarily by where they live. One manatee population ranges along the North American east coast from Florida to Brazil. Other species inhabit the Amazon River and the west coast and rivers of Africa. Manatees are born underwater. Mothers must help their calves to the surface so that they can take their first breath, but the infants can typically swim on their own only an hour later. Manatee calves drink their mothers' milk, but adults are voracious grazers.

They eat water grasses, weeds, and algae—and lots of them. A manatee can eat a tenth of its own massive weight in just 24 hours. Manatees are large, slow-moving animals that frequent coastal waters and rivers. These attributes make them vulnerable to hunters seeking their hides, oil, and bones. Manatee numbers declined throughout the last century, mostly because of hunting pressure. Today, manatees are endangered. Though protected by laws, they still face threats. The gentle beasts are often accidentally hit by motorboats in ever more crowded waters, and sometimes become entangled in fishing nets. Marine Mammal Species, Characteristics and Definition 1. Cetaceans (Whales, Dolphins and Porpoises) Cetaceans differ greatly in their appearance, distribution, and behavior. The word cetacean is used to describe all whales, dolphins and porpoises in the order Cetacea. This word comes from the Latin cetus meaning "a large sea animal," and the Greek word ketos, meaning "sea monster." There are about 86 species of cetaceans.

The term "about" is used because as scientists learn more about these fascinating animals, new species are discovered or populations are re-classified. Cetaceans range in size from the tiniest dolphin, Hector's dolphin , which is just over 39 inches long, to the largest whale, the blue whale , which can be over 100 feet long. Cetaceans live in all of the oceans and many of the major rivers of the world. More » continue reading below our video What are the Seven Wonders of the World Australian fur seals taken at Montague Island, NSW Australia. Alastair Pollock Photography / Moment / Getty Images 2. Pinnipeds The word "pinniped" is Latin for wing- or fin-footed. Pinnipeds are found all over the world. The pinnipeds are in the order Carnivora and suborder Pinnipedia, which includes all the seals , sea lions and the walrus . There are three families of pinnipeds: the Phocidae , the earless or ‘true’ seals; the Otariidae , the eared seals, and the Odobenidae, the walrus.

These three families contain 33 species, all of whom are well-adapted for a life spent on both land and in the water. More » Dugon swimming, Abu Dabab, Marsa Alam, Red Sea, Egypt. Borut Furlan / WaterFrame / Getty Images 3. Sirenians Sirenians are animals in the Order Sirenia , which includes manatees and dugongs, also known as " sea cows ," probably because they graze on sea grasses and other aquatic plants. This order also contains the Steller's sea cow, which is now extinct. The sirenians that remain are found along the coasts and inland waterways of the United States, Central and South America, West Africa, Asia and Australia. More » Sea Otter. heatherwest / Getty Images 4. Mustelids The mustelids are the group of mammals that include weasels, martens, otters and badgers.

Two species in this group are found in marine habitats - the sea otter (Enhydra lutris), which lives in Pacific coastal areas from Alaska to California, and in Russia, and the sea cat , or marine otter (Lontra felina), which lives along the Pacific coast of South America. 5. Polar Bears Polar bears have webbed feet, are excellent swimmers, and prey primarily upon seals. They live in Arctic regions and are threatened by decreasing sea ice. Did you know that polar bears have clear fur? Each of their hairs is hollow, so they reflect light, giving the bear a white appearance. More »

Question: What type of animal is also known as a sea cow?
Answer: Manatee