Steller's Sea Cow

• It is one of the best-documented extinctions in history: only 27 years passed between its scientific discovery and its disappearance.
• It had no teeth: it ground the kelp between two rough horny plates set in the palate and the jaw.
• It had lost its teeth. In their place it had two horny plates with which it ground up seaweed, and practically nothing else.
• It was the largest sirenian known: up to 9 metres and between 8 and 10 tonnes. A single animal was said to be able to feed 33 men for a month.
• Georg Wilhelm Steller was the only scientist ever to see it alive. He described it in 1741, when he was shipwrecked on Bering Island during Vitus Bering's expedition, and his posthumous account, De bestiis marinis, is almost everything we know of its behaviour.
• It could not submerge: it floated at the surface grazing on seaweed, which made it trivially easy to harpoon from a boat.
• A study of its genome published in 2021 found genetic diversity as low as that of the last mammoths of Wrangel Island, indicating that its decline had begun long before the Europeans arrived.
• Its disappearance may have altered the kelp forests of the North Pacific: it has been suggested that the kelp ecosystem we now regard as natural is in fact the one left behind after losing its great herbivore.

Skeleton type

Vertebrate - internal bony skeleton (mammal)

Habitat and environment

Cold, shallow waters of the Bering Sea, over kelp forests

Sources consulted: https://www.iucnredlist.org/ | https://animaldiversity.org/ | https://es.wikipedia.org/