Georg Wilhelm Steller spent nine months stranded on an island in the Bering Sea in 1741. If Steller had followed the fate of the expedition’s leader, Vitus Bering, and died of cold, hunger, or scurvy, we may today know far less about much of the wildlife on what became Bering Island. In particular, were it not for the time Steller spent observing and eating a large marine mammal during his time on the island, it is likely that the Steller’s sea cow would have been named after someone else.

As it happened, Georg Steller left Petropavlovsk, Russia aboard the ship the St. Peter in 1741 as the expedition’s naturalist and doctor. Later known as the Great Northern Expedition, the expedition’s goal was to find a northern sea route to North America and map the Pacific waters. When the St. Peter was shipwrecked and its crew stranded on Bering Island in November 1741, Steller spent the time exploring the island’s ecology and wildlife. The crew spent the winter rebuilding their ship and managed to rescue themselves and return to Russia in August 1742.

As the marine biologist Callum Roberts recounts in The Unnatural History of the Sea, “The rest, as they say, is history”.

Steller’s Sea Cow

The world knew of the Steller’s sea cow (Hydrodamalis gigas) for only little over two decades. By 1768, the Steller’s sea cow was considered extinct, due primarily to over hunting. What we know about the species, including perhaps the only remaining first-hand drawing of the species, comes from Steller’s observations during his time on Bering Island in 1741-42. The only living member of the sea cow’s family is the dugong (Dugong dugon). A massive, slow moving marine mammal, Steller’s sea cow weighed up to 6 tonnes and reached lengths around 8 meters.

By Steller’s time, the only recorded occurrence of the sea cow was in the Bering Sea. However, fossil evidence suggests that in the Pliocene and Pleistocene, it ranged from Japan to Baja California, Mexico. When Steller visited Alaska, it is likely that intensive prehistoric hunting had already substantially restricted the sea cow’s range.

“No one who has studied the life of the land doubts that the vast ocean is full of unknown creatures.”

Georg Steller, On the Beasts of the Sea

Today, we do not know how many sea cows once swam in the ocean. The sea cow went extinct before we had modern methods to accurately and precisely estimate its population. Scientists have examined records of hunting levels and the rate of extinction in attempts to estimate historic population levels. In a study published in Biology Letters, Turvey and Risley (2006) modeled the extinction of the sea cow to reconstruct its estimated population.

An 1887 estimate of the Bering Island sea cow population placed the numbers around 1,500 individuals. Based on the rate of hunting and the date of extinction in 1768, Turvey and Risley estimated that the initial prehuman Bering Sea population was probably closer to 2,900 individuals.

The sea cow lived primarily in shallow, cold waters, moving in and out from shore with the tides and grazed on kelp forests that formed its main habitat. As Steller described, “Like cattle on land, these animals live in herds together in the sea” and “are busy with nothing but their food.”

Georg Steller

Georg Steller was a German botanist, zoologist, physician, and explorer. He was born in 1709 and was described by the scientist Leonhard Stejneger, in his 1936 biography of Steller, as the “pioneer of Alaskan natural history”.

In June 1741, at the age of 32, Steller joined Bering on an expedition to document the natural heritage of Alaska. In his book Steller’s Island: Adventures of a Pioneer Naturalist in Alaska, Dean Littlepage paints a picture of the scene as the St. Peter dropped anchor off Alaska’s Kayak Island after seven weeks at sea, and Steller, “squeezed tightly against the rail, breathed in the view of dense forests against a background of great icy peaks like gulps of oxygen for his soul”.

While on the island, Steller raced around collecting and observing specimens. He documented no fewer than 140 species of plants in six hours. He also described a “black-crested, cobalt-blue bird so familiar today to the people of the Pacific Coast and the western mountains, the bird we call Steller’s jay”. He described a sea lion, an eider duck, an eagle, and the sea cow, all of which would come to bear his name.

Foresight of the Sea Cow

Why spend time trying to understand the story of an 18th century marine mammal that humans only really cared about for a couple of decades? If hindsight is twenty-twenty, the answer is that the story of the sea cow has a great deal to teach us about modern conservation and our future relationship with wildlife.

Much of the over hunting of the sea cow was to provision ships while on northern expeditions. In 1887, Leonhard Stejneger collected records of hunting and trading expeditions that stopped to resupply at Bering Island. Between 1743 and 1762, Stejneger recorded 19 expeditions that visited Bering Island that collectively killed 2,466 sea cows.

Turvey and Risley estimated that the annual maximum sustainable catch of sea cows in the mid-1700s would have been 17 individuals per year. Based on Stejneger’s records, an average of 123 individuals per year were killed. As Callum Roberts says, the sea cow “was an extinction waiting to happen”.

“Modelling sea cow extinction also highlights the catastrophic impact of wastefulness when overexploiting resources mistakenly perceived as ‘infinite’.”

Turvey and Risley, Modelling the extinction of Steller’s sea cow

One of the more troubling details of the sea cow’s decline and Turvey and Risley’s study is the amount of wastage factored into their estimates. In his records of expeditions that hunted sea cows at Bering Island, Stejneger documented eight expeditions that did not actually provision their ships. Remember that 19 ships visited Bering Island, all of which killed sea cows, but eight of them did not actually collect any of the meat from the 360 animals they killed for provisioning. Even using the much lower estimate of 1,500 individual as a reference, Turvey and Risley calculated that without wastage, the sea cow’s extinction would have been delayed until 1817.

The story of the sea cow teaches us about the catastrophic effects on wildlife and biodiversity of wasteful human activities. Modern hunting regulations typically prohibit meat wastage and even so-called “trophy hunting” requires meat to be retained and used. However, translated into modern times, the wasteful killing of sea cows stands in stark similarity to the widespread habitat degradation and destruction that occurs for industrial development and urban expansion. It is an example of how quickly wildlife can decline when we factor in the numbers that die unseen.

Kelp Forests

While over hunting was the primary driver of the sea cow’s extinction, scientists and historians have also noted the roles of habitat degradation and severed species interactions in extinction events. In The Unnatural History of the Sea, Callum Roberts says that while Bering Island was the last redoubt of the species, “its demise elsewhere was probably due to overexploitation by Indigenous peoples and loss of the sea cow’s kelp forest habitats, long before Bering’s voyages”.

Roberts goes on to explain, “This habitat loss, as we will see, was an indirect effect of human hunting of sea otters”.

Many ecology students are familiar with the concept of a keystone species, or a species that is so vital to its habitat that its removal changes the entire structure of the ecosystem. A notable example of a keystone species is the sea otter. Sea otters prey on sea urchins. Without this predation, sea urchins flourish and overgraze kelp forests. Therefore, without the sea otter’s role as a predator and keystone species, the habitat balance breaks down.

While we often hear about the sea otter-sea urchin-kelp forest connection, we rarely hear about its impacts on the Steller’s sea cow. By the time Steller reported on the sea cow, sea otters were hunted in extraordinary numbers for their fur. As Roberts explains, declines in sea otters would have “triggered an ecological disaster for sea cows as urchin populations expanded and grazing pressure increased”.

The final demise of the sea cow was most decidedly due to over hunting, but as Roberts explains, “their extinction is easier to understand in light of the role sea otters played in maintaining kelp forests”. In a study published in the journal PNAS, Estes, Burdin, and Doak (2016) explain that hunting was “largely responsible for the sea cow decline at Bering Island. However, our analyses suggest that the sea cow’s extinction from this last stronghold also was a nearly inevitable consequence of the loss of sea otters and kelp forests and would have occurred without any loss of sea cows to human hunting”.

The longer-term history of decline of the sea cow demonstrates the importance of habitat conservation and highlights what is now an approach to conservation that focuses on connectivity and corridors between key habitats.

The Thread of Whose History is Interwoven with Its Own

Steller and the rest of the crew eventually rebuilt their ship and rescued themselves from the island. For his part, Steller returned home with what remained the only detailed European description of a poorly understood, and certainly underappreciated, species. He published his observations of the sea cow in his paper On the Beasts of the Sea.

“Flints’ Pond! Such is the poverty of our nomenclature,” lamented Thoreau in Walden. “What right had the unclean and stupid farmer, whose farm abutted on this sky water, whose shores he has ruthlessly laid bare, to give his name to it?”

Thoreau was concerned about imposing on nature the names of those who had no relationship to the place. “Rather,” he continued, “let it be named from the fishes that swim in it, the wild fowl or quadrupeds which frequent it, the wild flowers which grow by its shores, or some wild man or child the thread of whose history is interwoven with its own.”

Would the relationship between Georg Steller and the sea cow have satisfied Thoreau’s criteria? Were the threads of their histories sufficiently interwoven?

Conclusion

When we think about Georg Steller and the sea cow – their interactions and shared fates, and their contributions to our wider understandings of nature and conservation – their stories are interwoven in an instructive and tragic way.

Callum Roberts describes it poignantly: “Sadly, Steller shared the misfortunes of his sea cow. He remained in Kamchatka another three years, writing up his scientific observations and getting arrested twice for arguing against Russian oppression of the Kamchadal people. Although exonerated, he took to drinking and died of a fever in his sled on the long journey back to St. Petersburg in the winter of 1746. His grave was robbed, his body feasted on by stray dogs, and eventually the Tura River washed away all evidence of his burial”.

Certainly, the sea cow is a dramatic lesson that wildlife is not infinite. We have seen that mistaken perception enacted numerous time since the sea cow’s extinction, including in fisheries and migratory birds. I worry about it today with perceptions of global seal populations.

Steller described that the sea cows were “not in the least afraid of human beings”. Callum Roberts notes that their “economic value, or value as food, combined with stupidity and defenselessness virtually guaranteed elimination”. But this should never be the case. As hunters and conservationists, we need to be cautious to never again so brazenly and mistakenly treat wildlife as though it is infinite.

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Header image: Thomas Jefferys: The Russian Discoveries, from the Map Published by the Imperial Academy of St. Petersburg. London, Printed for Robt. Sayer, Map & Printseller, No. 53 in Fleet Street. Published as the Act directs March 2d, 1775., London 1776