Manatees are huge animals that live in the sea and feed on underwater vegetation. Their weight is up to 600 kg, and in length they can reach 5 meters. Most likely, the ancestors of the manatees lived on land, but after that they decided to change their place of residence and moved to the water element. Initially, there were more than 20 species, but only three are known to man: Steller's cows, manatees and dugongs. The first, unfortunately, no, since the man completely destroyed this species.
What is a sea cow, people discovered for themselves in the XVII century, and immediately began to mercilessly exterminate them. The meat of these animals is very tasty, the fat is soft and tender, which is especially good for making ointments, and the skin of sea cows was used. Now manatees are declared an endangered species, and hunting them is prohibited. But still sea cows suffer from human activity. Now and then they swallow the nets and hooks that slowly kill them. Great harm to their health causes pollution of ocean waters, the construction of dams.
Because of the heavy weight of the enemies, the manatees are not that numerous. At sea, they are threatened by tiger sharks, and in tropical rivers - caimans. Despite the phlegmatic nature and slowness, they still manage to avoid certain death, therefore the main enemy of sea cows is man. It is impossible to catch them, but a large number of animals die under the propellers of the ships, so many countries are developing programs to save manatees.
The sea cow prefers to live in shallow water, the optimum depth for it is 2-3 meters. Every day, manatees eat about 20% of their weight, so they are specially bred in places where excessive vegetation spoils the water quality. They mostly feed early in the morning or in the evening, and rest during the day, swim to the shore to bask in the sun.
In total, there are three types of manatees: African, Amazonian and American. The African sea cow, as befits all Africans, is a bit darker than its relatives. She lives in warm equatorial rivers and on the West African coast. The Amazon manatee lives only in fresh water, so its skin is smooth and even, and on the chest and in some cases there is a white or pink spot on the stomach. The American sea cow prefers the Atlantic coast, especially she likes the Caribbean Sea. She can swim in both salty and fresh water. It is the American manatees are the largest.
It is very interesting to watch manatees, their tail looks like an oar, and their front paws with claws resemble flippers. They use them very skillfully, they can walk on the bottom, scratch, hold and stuff food in their mouths. Search for food, bask in the sun, play with other representatives of the species - that’s all the worries that the sea cow has assumed. Manatee mostly lives alone, only in the mating season the female is surrounded by about two dozen boyfriends.
A cub is born about a year old, at birth its weight is about 30 kg, and its length is slightly more than a meter. He lives with his mother for about two years, she shows him his usual places to search for food. Then the lamantani grows up and becomes independent. It is believed that their relationship is inseparable and maintained throughout life.
Sea cow: description, structure, characterization. What does a sea cow look like?
According to the description of Steller and the subsequent stories of industrialists, one can quite satisfactorily present the appearance and lifestyle of sea cows. They lived in shallow, sheltered coves, the bottom of which was overgrown with algae - kelp and fucus. The animal fed on these algae. Far into the sea, sea cows didn’t sail - kept all the time along the coast.
The body length of a sea cow reached six meters or more. The head of the animal was small, the upper lip - forked and covered with a large number of vibrissae - hard tactile hairs. Two front flippers had a length of up to one and a half meters each and had great mobility - with their help the animal not only swam, but also tore the algae from the bottom. When industrialists tried to pull a wounded cow onto the shore, she rested her fins so hard that sometimes skin was torn from them. “The ends of flippers are sometimes split, like the hooves of a cow,” say some industrialists. The animal body is a spindle-shaped, with a long and thin tail stem, on which sits a horizontal, very wide tail with a fringed rim. They do not have back flippers. The skin is dark, strong, with numerous grooves, reaching from the top down. Teeth to sea cows replace horny plates.
Skeleton of a sea cow.
What fed sea cows
Sea cows ate grass, as befits a cow. Clamping a sheet of kelp with flippers, they passed it through the upper forked lip. The tender leaf pulp fell into the mouth, and the hard rod was discarded.
According to Steller, the sea cow was found only around Bering Island. He also pointed out that by hunting these animals, one can provide plenty of meat for the inhabitants of Kamchatka.
Why are sea cows gone
Industrialists wintered on the island - three or four people. They ate mostly cabbage meat, as they called sea cows. Killing the gullible beast was easy. It was more difficult to pull the heavy carcass to the shore. Because of this, many dead animals disappeared.
Expeditions departing from Petropavlovsk to America, at the same time, visited Bering Island and slaughtered a certain number of animals to replenish their reserves. Herd of sea cows declined very quickly. Back in 1754, industrialist Yakovlev advised banning the trade of cows. But his advice was not accepted. The beating continued, and by 1770 the sea cows were gone. A whole species of animals was destroyed by man.
By the way, this is not the only example of the destruction of a valuable animal species by humans. How many sea cows were there when Steller saw and described them? He himself gives not very definite instructions to this effect, saying only that there were a lot of them: whole herds were carried out. Professor of the Moscow State University V. G. Heptyr believes that there could be about 2,000 of them.
Today, in none of the directories that list the names of now living representatives of the animal world, there is no name for ritin stellery (this is the name of the sea cow in the language of scientists). It is believed that it does not exist anymore on Earth.
Where lived disappeared sea cows
Steller wrote that the sea cow is found only on Bering Island. But industrialists said that large herds of these animals were found on the neighboring island of Mednoy.
Yes, only if near the Commander Islands lived sea cows? After all, on one of the Aleutian found their bones.
Far Eastern coast opened whalers and hunters. But they mostly did not leave any written documents about their voyages. Only one source that has come down to us is known: skipper Huck, who sailed on the Siberia schooner with the goal of discovering new whale fields and rookeries of the sea animal, has compiled a description of the unknown at that time the coast of Eastern Kamchatka between Cape Ilyinsky and Faddey. He opened several bays.
The rest of the information about the coast and the seas washing it came from naval sailors and from ships of the Russian-American Company. Special studies were few, and they covered only a few, relatively small sections of the coast.
A detailed study of the entire coast, stretching more than 3,000 kilometers in a straight line, has not been done up to our days. In 1919-1920, the Geographic Expedition of the Eastern Ocean, and in 1929-1930, a separate hydrographic detachment of the Far East conducted marine research here, based on which the Bering Sea Authority was compiled.
It states the following: “When using the Bering Sea charts, it must be remembered that the sea survey, on the basis of which they were compiled, is a reconnaissance record, these charts have little detail and rare ship measurements. The coastline is applied with an accuracy of 1 mile (on average). Therefore, seafarers are advised to be especially careful when approaching the coast, it is imperative to use the lot and not to go beyond the tack line of the coastal survey. ”
So it is written in the lot. And from these words it is clear that sea vessels practically do not happen near the coasts where a sea cow could survive. The local coast is small and rarely inhabited. For example, over the distance of 250 kilometers north of Petropavlovsk-Kamchatsky there are only two very small settlements on the coast. The main part of their inhabitants are seasonal workers who spend most of the year in the hills, away from the ocean. Locals hardly go to sea: they have no boats for coastal navigation. After all, on the local unequipped banks can not keep small vessels.
And the expedition of biologists? Weren't they in these parts? Were But either in the ocean, far from the coast, or went deep into the peninsula, in the hills. Walking along the coast is impossible: small bays with low shores alternate here with steep cliffs that end in the ocean.
There is one more circumstance that makes it difficult to study the coast in detail. Academician L. S. Berg writes about him. In the summertime - most of the expeditions are working at this time - the number of foggy days on the coast reaches its maximum and in July, for example, 73 percent.
From all the above, we can conclude that these places are little explored. Their inaccessibility and low population density can still hide Steller's sea cow from science, if only it lives in these places.
Genus of sea cows
Their second name is hydrodamalysis. The genus includes only two species of very large mammals, which are characterized by aquatic lifestyle. Habitat was limited to the northern part of the Pacific Ocean. The animals preferred calm and calm waters, where they would be provided with sufficient amount of plant food, and a lot of it was needed.
The sea cow is a herbivore, whose main ration was algae. Actually, for such a lifestyle and peaceful disposition, they received such a name by analogy with their land namesake.
The genus includes two species: hydrodamalis Cuesta and Steller's cow. Moreover, the first, according to scientists, is the historical ancestor of the second. For the first time, Cuesta hydrodamalys was described in 1978 on the basis of remains found in California (USA). This species died out approximately 2 million years ago. The exact reasons are not called, from the alleged - the cooling and the beginning of the era of the ice age, which resulted in a change in habitat, a decrease in food supply, etc. However, according to scientists, before the complete disappearance, this sea cow gave rise to a new and more adapted form.
Sea, or Stellerov, cow
In fact, the first name is generic, and the second - specific. Also this type is sometimes called cabbage, which is associated with the type of food. As already mentioned, the ancestors of the animals described are hydrodiemalis Cuesta. The Steller's cow was first discovered and described during the expedition of V. Bering. On board the ship was the only specialist with science education - Georg Steller. Actually, his name was later called this animal. Once, being on the coast after a shipwreck, he noticed large objects swaying in the waves, having an oblong shape and resembling boats turned upside down. But it soon became clear that these are animals. Kapustnitsa (sea cow) was described by G. Steller in sufficient detail; he did this on the example of a large female, sketches were drawn up, and observations concerning nutrition and lifestyle were recorded. Therefore, most of the later work is based on his research. The photo shows the skeleton of a sea cow.
What does a sea cow look like?
The external structure and type of cabbage are characteristic of all members of the Sirena order. The only significant difference is that it greatly exceeded contemporaries in size. The animals' body was rolling and thick, and the head, relative to its proportions, was small, but mobile. A pair of limbs consisted of flippers, short and rounded, having a horny growth at the end, often compared with the hoof. The body ended with a wide tail blade, having a notch in the middle and located in a horizontal plane.
It is noteworthy what kind of body covers the animal possessed. The sea cow, in the words of G. Steller, had a skin resembling the bark of an oak tree, it was so strong, thick and full of folds. Later, studies of the remains remained allowed to establish that in terms of its performance, it resembled modern rubber. This quality was clearly protective in nature.
The jaw apparatus had a rather primitive structure, the sea cow choked food with the help of two horny plates (on the upper and lower jaw), teeth were missing. The animal had an impressive size, which was one of the main factors for conducting active fishing on it. The maximum fixed body length is 7.88 meters. It should be noted that in a female of medium size (about 7 m) the body circumference in the widest place was about 6 meters. Accordingly, the body weight was huge - several tons (from 4 to 10). This is the second largest (after the whales) sea animal.
Animals were immobile and slow. Most of their lives they spent in the process of absorbing food. They swam slowly, preferred the shallow water, with the help of large fins rested on the ground. It is believed that sea cows are monogamous and lived by families who gathered in large herds. Their diet consisted solely of coastal algae, namely sea kale, hence the name.
For animals was characterized by a relatively high life expectancy (up to 90 years). Information about natural enemies is not available. Mr. Steller, in his descriptions, mentioned the death of animals during the winter period under the ice, as well as during a strong storm from strikes on stones. Many zoologists say that, with such a “docile” temper, the cabbage maid could become the first aquatic pet.
Sea cow: extinct or not?
The animal is officially considered extinct and is listed in the Black Book. The main reason is the active extermination of stellerovyh cows by man. By the time this species was discovered, it was already few in number. Scientists suggest that at that time the number of cabbages was about 2-3 thousand. In this state of affairs, it was permissible to slaughter no more than 15-17 individuals per year. In reality, this figure exceeded almost 10 times. As a result, about 1768, the last representatives of this species disappeared from the face of the earth. The task was simplified by the fact that Steller’s cow led a sedentary lifestyle, did not know how to dive and was not at all afraid of people coming closer. The main purpose of cabbage hunting is the extraction of meat and fat, which had high palatability, and the skins used in the manufacture of boats.
In the media and on television, they occasionally raise the topic that sometimes a sea cow is found in remote corners of the ocean. Was the cabbage woman dead or not? Scientists will definitely answer this question positively. Is it worth believing the "eyewitnesses" is a big question, because for some reason no one has provided photo and video materials.
According to many scientists, the dugong is the closest relative of the cabbage of the mammals living nowadays in the marine waters. The sea cow and he belong to the same family. Dugong is its only representative in the modern period. It is much smaller in size, the maximum fixed body length is about 5.8 meters, and its weight is up to 600 kg. The thickness of its skin is 2.5-3 cm. The largest population of dugongs (about 10 thousand individuals) now lives in the Torres Strait and off the coast of the Great Barrier Reef.
Possessing the structure and way of life similar to cabbage, this animal also became an object of fishing. And now the dugong is listed in the Red Book under the status of a vulnerable species. The sea cow was, unfortunately, eaten in the truest sense of the word. I want to believe that at least one representative of the Dugong family will still be saved.
10. Steller's (sea) cow
The sea (Steller's) cow is named after the Russian zoologist Steller, who first discovered and described this species of animal in 1741. The sea cow was slightly larger than the manatee, swam at the surface of the water and fed on seaweed (hence the name “sea”). The weight of the cows was up to 10 tons, and in length - 25 meters. The view from the very beginning was threatened with extinction, since the meat was very tasty and was widely eaten by the indigenous population. Fishermen and sealers joined the hunt for sea cows. The skins of cows were used in the manufacture of boats. As a result, the species of Steller's cow completely disappeared in less than 30 years.
9. The Quagga
Квагга обитала на юге Африки, окрасом спереди была похожа на зебру, а сзади – на лошадь. Это чуть ли не единственный истребленный вид, который был приручен людьми, чтобы охранять стада. Квагги имели способность быстрее коров, овец, кур замечать хищников и предупреждать хозяев об опасности криком “куаха” (отсюда и произошло их название). Квагги были уничтожены человеком ради мяса и шкуры в 1878 году.
8. Китайский речной дельфин (“байцзи”)
Китайский речной дельфин относится к отряду млекопитающих, представитель речных дельфинов. The view was discovered in China (Yangtze River) in 1918. This is a light gray dolphin with a whitish belly weighing about 42-167 kg, in length 1.4 - 2.5 meters. The expedition of 2006 did not find any individuals of the Chinese river dolphin, most likely the species completely disappeared (although in 2007 it was reported that 30 individuals remained in the Tianezhou reserve).
5. Tasmanian wolf (tilacin)
The Tasmanian wolf is the only representative of marsupial wolves, it is also called tilacin. The species is originally from Australia, the length of the individual reached a size of 100-130 cm, height - 60 cm, weight about 25 kg. The first mention of the Tasmanian wolf was found on rock records no later than 1000 BC. e. Europeans first encountered the marsupial wolf in 1642. In the 30s of the 19th century, the mass extermination of the beast by farmers began in order to protect their sheep. Thus, marsupial wolves survived only in remote areas of Tasmania by 1863.
4. Wingless Frog
The wingless auk - a large flightless bird reached a length of 75 to 85 cm, weighing about 5 kg, lived in the waters of the North Atlantic. The wingless auk has been known to people for more than 100,000 years, the natives have valued the birds for their tasty meat, eggs and down for making pillows. Due to overfishing of birds, the number of wingless auk was drastically reduced. By the middle of the 16th century, almost all breeding colonies of birds were systematically destroyed. The last individuals were caught and destroyed on the islands in Scotland in 1840.
3. wandering pigeon
The wandering pigeon belongs to the pigeon family, until the end of the 19th century it was the most common bird on Earth (there were approximately 3-5 billion individuals). The bird reached a length of 35-40 cm, weighing 250-340 g, distributed in the forests of North America. The extinction of the species occurred gradually due to a variety of factors, the main of which was human - poaching. The last dove died in 1914 in the zoo (USA).
Dinosaurs have inhabited the Earth in the Mesozoic era - for more than 160 million years. In total, there were more than 1000 species, which can be clearly divided into bird-striking (theropods - “animal-like” and sauropomorphic “lizard-legs”) and lizard-like (stegosaurs, ankylosaurs, ceratops, pachycephalosaurs and ornithopods) dinosaurs. The largest dinosaur is the spinosaur, which is 16-18 meters long and 8 meters high. But not all dinosaurs were large - one of the smallest representatives weighed only 2 kg and was 50 cm long. Dinosaurs died out 65 million years ago, according to one hypothesis the reason was the fall of an asteroid.