The extinction of Steller's sea cow
Steller's sea cow is the first sea mammal in modern times to be made extinct by human ignorance and greed.
Steller's sea cowThe Natural History Museum
Steller's sea cows (Hydrodamalis gigas) were extraordinary creatures.
Their closest living relatives are dugongs and manatees, known collectively as the sirenians. But while all four surviving species of sirenian live in warm tropical waters, Steller's sea cow had become highly specialised and only lived in to the sub-arctic waters of the northern Pacific Ocean.
This specialisation included growing to incredible sizes: adults could reach up to 10 metres (33 feet) in length while weighing up to 11 tonnes (12 tons), which is bigger than many modern whales. To put this into perspective, an adult male killer whale can be eight metres (26 feet) long and weigh up to six tonnes (6.5 tons).
Comparing a Steller's sea cow skull (right) with that of a modern dugong (left) also gives a good idea of just how big they were.
Within just 27 years of being formally described by scientists, humans had completely hunted this animal to extinction.
LIFE Photo Collection
Fashion victims
It was Europeans' insatiable desire for fur hats and coats that led to Steller's sea cow becoming an incidental victim of the international fur trade.
Russian fur traders discovered huge numbers of sea otters living around the islands scattered from Japan across what is now the Bering Sea and down into North America. This was the exact same habitat of the sea cows.
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As the traders made their way from Russia and China across to North America to hunt the otters, they would stock up on the meat of the Steller's sea cow to tide them over.
It was on one of these Russian expeditions that German zoologist Georg Wilhelm Steller first came across the marine mammals.
He would become the first and only scientist recorded to have seen the animals alive, having formally 'discovered' the sea cows in 1741.
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Almost every aspect of these animals made them easier for humans to hunt. Their diet of kelp forced them into shallow water, their social behaviour meant they didn't hide away, and their thick blubber not only meant that they stayed close to the surface, but also apparently made them particularly tasty.
By 1768, less than three decades after they were first described, the Steller's sea cow was extinct.
Steller's sea cowThe Natural History Museum
Learning from extinction
The cut marks on this vertebra are a poignant reminder of the sea cow's demise. However the speed at which the mammals were driven to extinction suggests that Steller's sea cows were probably never that numerous to begin with.
Steller's sea cowThe Natural History Museum
The fur traders probably never understood that the sea cow could be hunted out of existence, but it marks an important point in humanity's relationship with extinction.
For more information and to book tickets to the exhibition, visit the Museum's website.
