The Order
Sirenia has only two Families (
Trichechidae and
Dugongidae) and four extent species: the
West Indian manatee (
T. manatus), the West African manatee (
T. senegalensis), the Amazonian manatee (
T. inunguis), and the
dugong (
Dugong dugon). All four are often referred to as "sea cows." Technically, that is incorrect. There was only one "official" sirenian sea cow. That would be the Steller's Sea Cow (
Hydrodamalis gigas, formerly
Rytina gigas; Family
Dugongidae). And it's been
extinct since the
18th century.
Before his death, Tsar Peter I (Peter the Great), commissioned Danish navigator Captain Vitus Bering (after whom the strait is named) to determine whether Asia and the Americas were one or two separate continents. On his first voyage he concluded they were not. Upon return he decided to do a more expansive expedition to map the area of the Siberian coast, explore the flora and fauna, and the waters around it. On this second expedition in 1741 was a German doctor and naturalist named Georg Wilhelm Steller. During the expedition, Steller catalogued numerous species of plants and animals, some of which have his name attatched.
The two ships (the St. Paul and the St. Peter—which had both Bering and Steller) ran into rough seas and became seperated. The St. Paul was able to discover some of the Aleutian Islands. Bering made it to the Gulf of Alaska and was able to study some of the southwestern coast, the Alaska Peninsula, and the Aleutians. But by then many of the men were suffering from scurvy due to having run out of fruit and vegetables, Bering included.
The ship ran ashore on an uninhabited island that would be named "Bering Island" in his honor (he also died there that winter). It is part of the Komandor Islands which are in the southwestern Bering Sea about 180 km (110 miles) east of the Kamchatka peninsula.
It was a harsh winter and many were sick. The men had to survive by hunting. They were able to kill some smaller game but it was the discovery of an enormous sea dwelling mammal that helped much in their survival (they only had to kill two).
Steller, a naturalist, was interested in these huge animals and studied them, writing in his journal and having sketches made, a lot during the months they were shipwrecked. He is the only scientist to not only have studied them but to have seen them alive. It is from the sketches and notes that scientists have been able to make approximations of their appearance with the help of surviving skeletons (some skin also has been preserved in museums).
The creatures were as much as 8.5 m (28 feet) long and 6.7 m (22 feet) around. They weighed up to 3628 kg (8000 pounds). They had no teeth, only two flat (not exactly flat, as they were furrowed and ridged a certain amount) white bones, one part of the palate and the other on the inside of the lower jaw, suitable for grinding their food. Like the surviving members of Sirenia, they were herbivores. The sea cow's diet consisted of seaweed (primarily kelp). Around the mouth area were strong bristles.
Despite the great size of the creatures, they had very small heads—proportionally compared to the dugong, it would only be about half the size. The hide was wrinkled and black. It was tough, at least 2.5 cm (1 inch) thick, with a fat layer of 10.1-22.8 cm (4-9 inches) beneath it (helpful due to the near arctic conditions—the only member of the family that lived anywhere near that latitude). It had a lobed tail and its fore appendages (flippers) were thick but had no "finger bones.". The sea cow had very small eyes and even though the ear holes were tiny (reportedly the size of a pea—for context, refer back to the size of the creature), it had large internal ear bones, meaning it probably had excellent hearing.
The animal reportedly tasted like beef or veal (where the name apparently came from) and kept longer than the meat of other available animals. The sailors also boiled and drank the fat, which was said to taste like "sweet almond-oil" (arcticculture.about.com). It was the sea cow as a source of sustenance that allowed them to last out the winter and build another boat from the wreckage of the St. Peter in order to escape. They also used the skin to aid in the building.
News of the discovery, not just of the cow, but of other fur-bearing animals, brought many sailors to the region where the sea cow was sadly and predictably and extensively hunted. Harpoons and rifles were used to kill them—though many escaped only to die elsewhere of the wounds. They were easy targets, never moving fast, and often inactive while digesting their food. Another problem was that other sea cows would swim over to ones that were " wailing" in pain and fear from being attacked. This only made more victims.
It's been estimated that the population at the time of discovery was between 1500-2000 (though possibly somewhat more) and was probably fairly stable. By 1755, there already were concerns about the population's decline. In 1768 (only 27 years later) the last reported sea cow was killed. Steller, having himself died only four years after the expedition, never knew of the extinction of the animal that bore his name.
Some of Steller's description:
These animals, like cattle, live in herds at sea, males and females going together and driving the young before them about the shore. They are occupied with nothing else but their food. The back and half the body are always seen out of the water. They eat in the same manner as the land animals, with a slow forward movement. They tear seaweed from the rocks with the feet and chew without cessation. During the eating they move their head and neck like an ox, and after the lapse of a few minutes they lift the head out of the water and draw fresh air with a rasping and snorting sound after the manner of horses. Where they have eaten, they leave many torn-off plants drifting around.
Since the 1800s, there have been reported sightings of small colonies in remote areas away from
Russian fishing grounds and boat traffic. In 1962 a Russian
whaling vessel reported seeing six sea cows feeding and in 1977 there was a report of a fisherman from Kamchatka who touched an animal resembling the Steller's sea cow.
Sometimes it's nice to believe extinction just might not be forever.
(Sources: www.sirenian.org, http://arcticculture.about.com/culture/arcticculture//library/yafeatures/bl-seacow.htm, http://home.t-online.de/home/rothauscher/steller/steller.htm, www.britannica.com)
It should be noted that the other four surviving members of the Order Sirenia are in danger of extinction.