The Great Sea Cow, also known as the Giant Dugong, toothless Manatee or Stella Manatee, is an extinct giant mammal. They are the largest known species of manatees, larger than their close relatives, manatees and dugongs! They are also the only species of manatees that have survived to modern times to adapt to the cold climate.
The great cattle were discovered in the Bering Strait in 1741 by the naturalist George Stella, who was traveling with the explorer Vitas Bering, the only biologist known to have seen the living body of the great sea cow. At that time, the number of large cattle was very small, and only 1,000 to 2,000 heads remained. It lives mainly in the offshore waters near Bering island and Copper Island in the Comandor Archipelago.
Georg William Stelle
Georg Wilhelm Steller
March 10, 1709 - November 11, 1746
German botanist, zoologist, doctor and explorer working in Russia. He was born in Windsheim, near Nuremberg, and studied at the University of Halle-Wittenberg. After graduation, he came to Russia in November 1734 and worked at the St. Petersburg Academy of Sciences (now the Russian Academy of Sciences). Later, he accompanied the Russian explorer Bering to Siberia, the Arctic Sea coast, kamchatka and Alaska to carry out exploration and research activities.
When the great sea cattle were first discovered by humans, their range was roughly around the Commandery Islands in the Bering Sea, east to the west of the Aleutian Islands and west to the Kamchatka Peninsula.
According to the fossil discovery records of the Pliocene and Pleistocene, the distribution range of the large sea cattle in the past may have reached as wide as the entire north-central coast of the North Pacific Ocean, reaching the Baja California Peninsula on the east side and the west coast of present-day Mexico at about 30 degrees north latitude, and the western part to Honshu in Japan (about 37 degrees north latitude in the south).
The sea cow is about 7.5 meters long and weighs 4500 to 5900 kilograms, and some large individuals can grow up to 10 meters long.
The forelimbs of the sea cow are thick but short, paddle-shaped, and the tail resembles a dugong.
The ratio of the skeleton of the great sea cow to the human
A model of a great sea cow
Discoverer Stella describes them: "This animal never came near the beach, always perched in the water, the skin was dark and thick, like the bark of a rubber tree, and its head was small according to the proportions of the body parts. There were no teeth, only two flat and white bones in the mouth, one in the upper jaw and one in the lower jaw. ”
Illustration of "The Teeth of the Great Sea Cow" in the mid-18th century
Written by Johann Christian Daniel von Schreber
In addition to not having teeth, another feature of the great sea cow is that there are only carpal and metacarpal bones at the ends of the forelimbs, and the phalanges degenerate to almost completely disappear, unlike manatees or dugongs.
The skeleton of the sea cow
Finnish Museum of Natural History
The skull of a sea cow
Natural History Museum, London
The sea cow feeds on a variety of large seaweeds that grow on the rocky shores, and only the soft parts are eaten, and it is said that every time the sea cows ate the kelp, the stems and roots of the kelp would be washed ashore. They are the only manatees in the order to feed on algae, although they occasionally eat seaweed, but this claim is controversial.
They do not seem to be able to dive, at least when feeding, they only bury part of their bodies in the water, nibbling on large algae near the surface of the sea near the tide line on the shore, and their foraging depth is estimated to be no more than 1 meter deep. Stella's account states that they would "eat en masse, and the cubs would be surrounded by the center of the group for protection." ”
There are parasites both inside and outside the great sea cow, and several species of crustaceans parasitize on the skin. Predators may include killer whales and large sharks.
Because the great sea cow is not afraid of humans, and because its range is close to the shore and its movement is slow, it is quite easy to catch. Stella described them as "never barking, even when injured," though it is unclear whether groups communicate with each other by their voices.
When a companion is injured, other big cattle will try to rescue them, and according to the hunters, they will try to pull out the harpoon from the injured companion.
In the literature on the great sea cow, it has been mentioned that 1 female sea cow was killed and dragged to land, while the other male sea cow that traveled with it stayed on the shore and refused to leave for at least 2 days. Together with other group observation records, it is judged that the sea cow may be 1 husband and 1 wife, and the spousal relationship may last for a long time. However, this is only a speculation made by people at that time based on the social background of the time.
Stella's records mention that the big sea cattle mate in early spring, the pregnancy period is more than 12 months, and they can give birth all year round, but autumn is the peak of childbirth. In fact, Stella spent time on Bering from the end of November 1741 to August 1742, and it seems that he may not have seen the newly born sea cow with his own eyes.
Shortly after the discovery of them, the Bering Sea region flooded with hunters whose goal was to hunt the local sea otters and northern fur seals for fur, and the need for supplies caused the tragedy of the sea cattle. These people hunted large numbers of sea cattle, ate their flesh, and used their skins to build and repair ships.
The last of the great sea cattle were known to have been captured on Bering island in 1768, just 27 years after Stella discovered their existence. Some scholars believe that the decline of sea otters may also be one of the reasons for the extinction of sea cattle, and among other animals living in the Bering Sea, sea otters may be the mammals most closely related to them, because sea otters will catch sea urchins that eat seaweed, and if the sea urchin is allowed to increase endlessly, the seaweed forest will soon be destroyed. Therefore, the reduction of sea otters at that time may also have put the sea cattle under pressure of food shortages.