The sea cow is a detachment of large aquatic mammals that became extinct faster than any other animals. Only 27 years have passed since the discovery of the species until its complete disappearance. Scientists have nicknamed the creatures sirens, but they have nothing to do with mythical mermaids. Sea cows are herbivorous, silent and peaceful.
Species origin and description
The family began its development in the Miocene epoch. As they moved to the Pacific North, the animals adapted to the colder climate and grew in size. They fed on cold-resistant sea plants. This process led to the appearance of sea cows.
Video: Sea cow
The species was first discovered by Vitus Bering in 1741. The navigator named the animal a Steller's cow in honor of the German naturalist Georg Steller, a doctor traveling with the expedition. Most of the information about sirens is based on his descriptions.
Interesting fact: Vitus Bering's ship “Saint Peter” was wrecked off an uncharted island. After disembarking, Steller noticed many bumps on the water. The animals were immediately nicknamed cabbage girls because of their love for kelp – seaweed. The sailors fed on the creatures until they finally got stronger and set off on their further journey.
Study of unknown creatures was not possible, since the crew had to survive. Steller was at first sure that he was dealing with a manatee. Ebberhart Zimmerman in 1780 took out the cabbage as a separate species. Swedish naturalist Anders Retzius in 1794 gave her the name Hydrodamalis gigas, which literally translates as a giant water cow.
Despite severe exhaustion, Steller was still able to describe the animal, its behavior and habits. None of the other researchers managed to see the creature live. Until our time, only their skeletons and pieces of skin have been preserved. The remains are in 59 museums around the world.
Appearance and Features
According to Steller's description, the cabbages were dark brown, gray, almost black. Their skin was very thick and strong, naked, bumpy.
Together with their ancestor hydromalis Cuesta, sea cows surpassed all aquatic inhabitants except whales in size and weight:
- length Steller cow – 7-8 meters;
- weight – 5 tons;
- neck circumference – 2 meters;
- shoulder circumference – 3.5 meters;
- belly circumference – 6.2 meters;
- the length of hydrodamalis Cuesta is more than 9 meters;
- weight is up to 10 tons.
The body is thick, spindle-shaped. The head is very small compared to the body. At the same time, mammals could move it in different directions, up and down. The body ended in a forked tail, shaped like a whale. The hind limbs were missing. The front ones were flippers, at the end of which there was a growth called a horse's hoof.
A modern researcher working with a preserved piece of skin found that it is similar in elasticity to current car tires. There is a version that this property protected the sirens from damage from stones in shallow water.
The ears in the folds of the skin were almost invisible. The eyes are small, about the size of a sheep. On the upper lip, which was not forked, there were vibrissae, as thick as a chicken feather. The teeth were missing. They chewed cabbage food with the help of horny plates, one on each jaw. Judging by the preserved skeletons, there were about 50 vertebrae.
Males are slightly larger than females. The siren made almost no sound. They only exhaled noisily, diving for a long time under the water. If they were hurt, they moaned loudly. Despite the well-developed inner ear, indicating good hearing, the creatures practically did not react to the noise made by the boats.
Now you know whether the sea cow is extinct or not. Let's see where these unusual animals lived.
Where does the sea cow live?
Studies show that the distribution range of mammals grew during the peak of the last glaciation, when the Pacific and Northern oceans were separated by land, where the Bering Strait is now located. The climate at that time was milder and cabbages settled along the entire coast of Asia.
Finds dated 2.5 million years ago confirm the existence of animals in this area. During the Holocene, the range was limited to the Commander Islands. Scientists believe that in other places the sirens could disappear due to the persecution of primitive hunters. But some are sure that by the time of discovery, the species was on the verge of extinction due to natural causes.
Despite the data of Soviet sources, IUCN experts found out that in the 18th century, the cabbages lived off the Aleutian Islands. The former pointed out that the remains found outside the known distribution area were only corpses that were carried away by the sea.
In the 1960s and 1970s, parts of the skeleton were found in Japan and California. A relatively complete skeleton was found in 1969 on the island of Amchitka. The age of the finds is 125-130 thousand years ago. On the coast of Alaska in 1971, the right rib of the animal was found. Despite the small age of the sea cow, the size was equal to adults from the Commander Islands.
What does a sea cow eat?
Mammals spent all their time in shallow water, where algae grew in abundance, which they fed. The main food was seaweed, thanks to which the sirens got one of their names. Eating algae, animals could stay under water for a long time.
Every 4-5 minutes they surfaced to take a breath of air. At the same time, they snorted noisily, like horses. Large quantities of roots and stems of plants eaten by them accumulated in the places of feeding of cabbages. The thalli, together with dung resembling horse dung, were thrown ashore in large piles by the waves.
In summer, cows ate most of the time, stocking up on fat, and in winter they became so thin that one could easily count their ribs. The animals clamped the leaves of algae with flippers and chewed with toothless jaws. That is why only the pulp of sea grass was eaten.
Interesting fact: Dr. Steller described mammals as the most voracious animals he had ever seen. According to him, insatiable creatures constantly eat and are not interested in what is happening around. In this regard, they lack the instinct of self-preservation. Between them, you can safely swim in boats and choose an individual for slaughter. Their only concern was to come up to breathe.
Character and Lifestyle Features
Most of the time, the sirens spent in shallow water, well warmed by the sun, eating marine vegetation. With their forelimbs they often rested on the bottom. The creatures did not know how to dive; their backs always stuck out on the surface. They dived only due to the high bone density and low buoyancy. This made it possible to be at the bottom without significant energy consumption.
Cow backs towered above the surface of the water, on which seagulls landed. Other seabirds also helped sirens get rid of crustaceans. They pecked out whale lice from folds in the skin. Trusting animals approached the shore so close that sailors could touch them with their hands. In the future, this trait negatively affected their existence.
Cows were kept by families: mom, dad and kids. They grazed in crowds, next to the rest of the cabbages, gathered in clusters of up to hundreds of individuals. The cubs were in the middle of the herd. Attachment between individuals was very strong. In general, the creatures were peaceful, slow and apathetic.
An interesting fact: Steller described how the partner of the killed female swam for several days to the killed female, who was lying on the shore. The baby cow that the sailors slaughtered behaved in a similar way. Mammals were not at all vindictive. If they swam ashore and hurt them, the creatures moved away, but soon returned again.
Social Structure and Reproduction
Even though the cabbages grazed in groups, it was still possible to distinguish clusters of 2, 3 in the water , 4 cows. Parents did not sail far from the cub of the year and the baby born last year. The pregnancy lasted up to one year. Newborns fed on mother's milk, between the fins of which were the nipples of the mammary glands.
According to Steller's descriptions, the creatures were monogamous. If one of the partners was killed, the second did not leave the body for a long time and sailed to the corpse for several days. Mating took place mainly in early spring, but in general the breeding season lasted from May to September. In late autumn, the first newborns appeared.
Being apathetic creatures, the males still fought for the females. Reproduction was very slow. In the vast majority of cases, one cub was born in the litter. Very rarely two calves were born. Mammals reached puberty at the age of 3-4 years. Childbirth took place in shallow water. The babies were quite mobile.
Their dimensions were:
- length – 2-2.3 meters;
- weight – 200-350 kg.
Males do not take part in raising cubs. While feeding the mother, the babies cling to her back. They feed on milk upside down. They feed on mother's milk up to one and a half years. Although already at the age of three months they can pluck the grass. Life expectancy reached 90 years.
Natural enemies of sea cows
The forwarding doctor did not describe the natural enemies of the animal. However, he noted that there were repeated cases of the death of sirens under the ice. There were situations when, during a strong storm, the waves were so high that the cabbages hit the stones and died.
The danger came from sharks and cetaceans, but the most tangible damage was caused to the population of sea cows by humans. Vitus Bering, together with his group of sailors, were not only the discoverers of the species, but also caused its extinction.
During their stay on the island, the team ate cabbage meat, and upon returning home, they told the world about their discovery. Hungry for profit, fur manufacturers went to new lands in search of sea otters, whose fur was very much appreciated. Numerous hunters filled the island.
Sea otters remained their target. They used cows exclusively as food. Killed them without counting. More than they could eat and generally pull out onto land. Sea otters were able to survive the invasion of hunters, but the sirens failed to survive their raids.
Interesting fact: Forwarders noted that the meat of mammals was very tasty and resembled veal. Fat could be drunk in cups. It was stored for a very long time even in the hottest weather. In addition, Steller's milk was sweet as sheep.
Population and species status
The American zoologist Steineger in 1880 made rough calculations and found out that at the time of the discovery of the species, the population did not exceed one and a half thousand individuals. Scientists in 2006 assessed the possible factors that influenced the rapid extinction of the species. According to the results, it turned out that for the extermination of the sirens over a 30-year period, hunting activity alone was enough for the complete extinction of these creatures. The calculations made showed that no more than 17 individuals per year were safe for the further existence of the species.
In 1754, the industrialist Yakovlev proposed a ban on catching mammals, but they did not listen to him. During the years 1743-1763, the industrialists slaughtered approximately 123 cows annually. In 1754, a record number of sea cows were destroyed – more than 500. At this rate of extermination, 95% of the creatures should have disappeared by 1756.
The fact that the sirens survived until 1768 indicates the presence of a population near Medny Island. This means that the initial number could reach up to 3000 individuals. The initial quantity makes it possible to judge the existing threat of extinction even then. The hunters followed the route drawn up by Vitus Bering. In 1754, Ivan Krasilnikov was engaged in mass extermination, in 1762 skipper Ivan Korovin led the active pursuit of animals. When the navigator Dmitry Bragin arrived with the expedition in 1772, there were no more Steller cows on the island.
27 years after the discovery of the huge creatures, the last of them was eaten. At that moment, when in 1768 the industrialist Popov was finishing his last sea cow, most of the world's researchers did not even suspect the existence of this species. Many zoologists believe that mankind has missed a wonderful opportunity in the form of breeding sea cows, like land cows. Thoughtlessly exterminating the sirens, people destroyed a whole species of creatures. Some sailors claim to have seen flocks of cabbage bugs, but none of these sightings have been scientifically confirmed.