Probably most people like salmon dishes. However, although we know this fish was available in rivers and seas for a long time, science still does not know when humans started using it for food. Now scientists at Washington State University and partnering science institutions have found the earliest known evidence that Ice Age humans in North America used salmon as a food source. This discovery counters the long-held idea that humans from that particular age primarily hunted big animals.
The findings of the research are based on analysis of 11,500-year-old chum salmon bones found during excavations at the Upward Sun River site. There scientists found human dwellings, tools and human remains, as well as the salmon bones. Anthropologist Carrin Halffman, lead author of the study from University of Alaska Fairbanks, explained that it means that now science knows that salmon was consumed as a food source even 11,500 years ago.
Findings also reveal some new knowledge about salmons too. They suggest that salmon spawning runs were established much earlier and much farther north than previously thought – at the end of the Pleistocene epoch, also known as the last Ice Age.
Genetic study of ancient DNA of found fish remains used innovative techniques in order to identify the remains to the species level. It is particularly difficult to analyse such old remains, there are only a few laboratories in the world who could actually conduct such research.
Brian Kemp, co-author of the study who was responsible for the genetic study of the remains, explained: “the combined genetic and isotopic data demonstrate that predictable chum salmon runs were occurring from the Pacific Ocean to the far interior of Alaska by at least 11,500 years ago. This sets up a scenario in which these abundant salmon could have been processed and stored, although for this we have no evidence yet.”
Scientists think that human may have went to particular places annually in order to feed from salmon, which is why this information about salmon spawning runs is relevant from anthropological point of view too. Even though currently there are no evidence supporting this idea, research does have enough proofs to negate long-held thought that humans in that particular age relied on hunting big animals, like mammoths and bison.
Scientists conducted the ancient DNA and stable isotope analyses and verified the fish remains are of the sea-run chum salmon that migrated upriver nearly 900 miles from where the mouth of the Yukon River now exists. This means that modern salmon migration paths may have ancient roots, dating back to at least the end of the last Ice Age.
Scientists explained that there were cases when salmon became landlocked, which changed their isotopic signatures. This knowledge helped scientists to identify salmon remains as chum salmon, which still inhabit the area today, and to understand their life histories, which is important in bettering understanding of how humans used salmon as resource for food.
These remains of salmons were actually found in an ancient cooking hearth in a residential structure. This is a big challenge for archaeologists too, because fish remains are very delicate to handle. Fish bones are usually very small, fragile and typically do not preserve well, which is one of the reasons why in global archaeological studies and findings fish remains are mentioned only sporadically.
Scientists say that this research expands the understanding about ancient Beringian diets, which now appear to be much broader than previously thought. It also shows that humans from Ice Age used much more complex strategies and technology to obtain their food that previous researches might have shown. Furthermore, even though there is no evidence now, scientists think that salmon runs were probably present few thousand years before too, which means salmon as a food source may have played a role in the early human colonization of North America.
Studies of diet of humans of the past are always very interesting, because they show how human lifestyle correlated with search for food. There are still many questions remained to answer and we will have to wait and see how this research develops further and what other findings may be made. But even now it is interesting to know that humans during the last Ice Age did not rely solely on big animals as a source for food.