Steller's Sea Cow: Humanity's First Marine Mammal Casualty
Imagine a world where the gentle giants of the sea, known as sea cows, gracefully roamed the waters. These magnificent creatures, which include manatees and dugongs, are not only iconic but also face threats that have put them on the brink of extinction. But what if I told you this isn't the first time humans have caused such devastation?
Currently, there are four surviving species of sea cows, commonly referred to as sirenians. However, in the 18th century, another species was thriving off the coast of Russia’s Kamchatka Peninsula, particularly around the Commander Islands in the Bering Sea: Steller’s sea cow (Hydrodamalis gigas). This remarkable creature was closely related to today’s dugongs and was first recorded by the biologist Georg Wilhelm Steller in 1741, after his expedition to North America became stranded on Bering Island. Unbeknownst to him, he would be the last scientist to ever see this majestic species alive.
Steller’s sea cow was believed to have been significantly larger than today’s manatees and dugongs, with estimates suggesting they could reach lengths of up to 9 meters (approximately 29.5 feet) and weigh around 10 tons. Some individuals had a thick layer of blubber that measured nearly 23 centimeters (about 9 inches) in certain areas, providing them with insulation in their cold ocean habitat.
In his extensive observations made during a ten-month stay on Bering Island, Steller noted that the population of these large mammals was so abundant that they could easily support all the residents of Kamchatka. However, modern research suggests that their numbers were actually quite limited. Several factors worked against their survival: they had a diet solely consisting of kelp, restricting their habitat to shallow waters; their slow movement prevented them from diving deep; and they displayed a lack of fear towards humans. Interestingly, some studies indicate that Steller’s sea cow might have faced extinction eventually, even without human interference.
Ultimately, it was human activity that sealed their fate. Fur traders in the Bering Sea began to hunt Steller’s sea cows relentlessly for their meat and blubber, which Steller himself described as tasty. Moreover, these hunters also targeted sea otters, the vital guardians of the kelp forests that the sea cows depended on.
Due to this relentless hunting pressure, Steller’s sea cow is believed to have vanished by 1768, just 27 years after its discovery. This event is significant, as it marks the first acknowledged instance of a marine mammal being driven to extinction due to human actions.
Fortunately, we are now more aware of the challenges facing the remaining species of sea cows. Efforts are underway to ensure that they do not meet the same tragic end as Steller’s sea cow. And when conservation initiatives succeed, the sight of these magnificent creatures thriving again is both awe-inspiring and heartwarming.
