When scientists dig through the trash left behind by prehistoric cultures to determine things such as diet, their assessment is typically based on visual clues, including bone and shell fragments.
But doing that, say the authors of a paper published Tuesday in the journal Nature Communications, may be giving us the wrong impression of the breadth of prehistoric diets. Specifically, the paper looked into the diet of the Saqqaq culture, who were the first humans to inhabit Greenland, some 4,000 years ago.
By using a new technique that analyses traces of DNA in ancient middens, rather than bone fragments, the scientists have found evidence that instead of relying mainly on seal, as was originally believed, the Saqqaq also ate large mammals, such as caribou, walrus and, surprisingly, whales.
One of the reason for the absence of bones from these types of animals in Saqqaq middens, the scientists suggest, is, that because of their size, they were butchered where they were killed, and only meat and fat was brought back to settlements, rather than hard tissue, such as bone, that would not break down.
Another reason why archaeologists looking solely at bones have no reason to consider whether whales in particular might have formed part of the diet is because there is no evidence that the Saqqaq developed the harpoons or other weapons used by other prehistoric Arctic cultures that hunted large whales.
The scientists posit two possible explanations for how the Saqqaq may have been able to hunt whales without having developed such hunting technology. Both hinge on the type of whale the DNA indicates was being consumed.
Bowhead whales were likely present in large numbers relatively close to the shores near Saqqaq settlements close to present-day Disko Bay. This would have meant a steady supply of dead whales that would have been easily scavenged and used for food and fuel.
The other explanation lies in hunting methods used in more modern times: traditional Greenland and Aleut hunters are known to have snuck up on whales and killed them with a piercing blow from behind. Alternatively, a non-lethal blow may have been used to wound or immobilise a whale, eventually causing it to drown after several days.
This process, the scientists suggest, may have been aided by ‘poisoning’ hunting lances or spears with rotten meat or blubber. A similar method was reportedly used by the Aleut in the 18th century, who dipped hunting tools in aconite, a plant-based toxin.
Typically, Europeans are considered to have been among the first to develop the technology to hunt large whales systematically, in the 15th century. Finding whale DNA in middens dating back at least 1,500 years before that, “requires re-evaluating” our view of whaling and the development of early Arctic cultures, reckon to the authors.
The findings, they conclude, “push back the first evidence of whale product usage in the Arctic and can be seen as a logical development of the powers of indigenous observation and ingenuity in the efficient use of a plentiful northern marine energy resource”.
Prehistoric Arctic residents, it would appear, did not need to live on seal alone.