work on excavation at the Upward Sun River site in Alaska.
(photo courtesy of Ben Potter, UAF)
Researchers in Alaska have found the earliest known evidence
that Ice Age humans in North America used salmon as a food source,
according to a new paper published this week in the Proceedings
of the National Academy of Sciences.
The findings counter traditionally held beliefs that Ice Age
Paleoindians were primarily big-game hunters. They are based on
analysis of 11,500-year-old chum salmon bones found by University
of Alaska Fairbanks anthropologist Ben Potter and colleagues at
the Upward Sun River site in Interior Alaska. Excavation of the
site has revealed human dwellings, tools and human remains, as well
as the salmon bones.
"Salmon fishing has deep roots, and we now know that salmon
have been consumed by North American humans at least 11,500 years
ago," said lead author Carrin Halffman, a UAF anthropologist
who helped analyze the fish bones with co-authors Brian Kemp of
Washington State University, Potter and others.
The findings also 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.
Ancient DNA and stable isotope analysis verified the fish remains
as sea-run chum salmon that migrated upriver some 1,400 kilometers
from where the mouth of the Yukon River now exists. These analyses
indicate that modern salmon migrations may have ancient roots, dating
back to at least the end of the last Ice Age.
"We have cases where salmon become landlocked and have
very different isotopic signatures than marine salmon. Combining
genetic and isotopic analyses allow us to confirm the identity as
chum salmon, which inhabit the area today, as well as establish
their life histories," said Potter. "Both are necessary
to understand how humans used these resources."
The salmon were found in an ancient cooking hearth in a residential
structure. Fish remains pose a challenge to archaeologists because
their bones are very small and fragile and typically do not preserve
well. Because of these challenges, their remains are likely underrepresented
in global archaeological studies and findings.
Findings show that ancient Beringian diets were broader than
earlier thought and that Ice Age humans used complex strategies
and specialized technology to obtain their food, Potter said. He
also noted that there is no evidence to suggest that salmon runs
weren't also present in the area a few thousand years prior
to the time when people were living at the Upward Sun River site.
"This suggests that salmon fishing may have played a role in
the early human colonization of North America."
The excavation and analysis were funded in part by the National
Science Foundation. Other contributors to the paper include UAF
postdoctoral researcher Holly McKinney, Bruce Finney of Idaho State
University, and Antonia Rodrigues and Dongya Yang of Simon Fraser