Paisley, south-central Oregon, United States
Paisley Caves
Coprolites by 12,300 radiocarbon years ago (human DNA in the dated dung)
In a cave above a vanished Oregon lake, dried human feces carry DNA of Native American founding lineages and a radiocarbon age of 12,300 years, more than a millennium before Clovis on that same clock. The catch is whether the DNA and the dung are the same event, or whether a later body left a trace that soaked down.
Why this is extraordinary
The Paisley Caves are shallow shelters in a volcanic ridge above a dry Pleistocene lake in south-central Oregon. What made them famous is not a fluted point. It is dung. In 2008 a genetics paper reported human mitochondrial DNA from coprolites, the dried feces, and radiocarbon dates on those same coprolites of 12,300 radiocarbon years before present. The DNA fell into haplogroups A2 and B2, two of the founding lineages of Native American peoples. The paper's comparison was blunt. That is more than a thousand radiocarbon years older than the Clovis dates then in use, about 11,000 to 10,800 radiocarbon years.
So the clock is on the person, in a way bone usually is not. A stone tool dates a visit only if you trust the layer. A coprolite that is human, dated on its own carbon, is the visit. Later work at the caves put the oldest of those coprolites as far back as 14,525 calendar years, and described the Pleistocene layers as stable despite the occasional rodent hole. The only late ice-age stone tradition the excavators identify is the Western Stemmed points, a different idea from Clovis, reaching back at least into Clovis times and argued to be older.
The catch is the sort of catch caves invite. DNA drifts. Later visitors, and animals, leave genetic traces that can leach downward, and a carnivore's dropping can pick up human DNA without a human having sat there. The 2008 study and the later blind checks at other laboratories are the answer on offer. Few obvious tools sit with the oldest dung, which is either a problem for a human reading or a description of people who were eating and not knapping in that particular corner.
A 2020 lipid study sorts the dung by its fats. Of 18 coprolites called human by that DNA, 10 match human lipids, 6 match carnivores, and 1 is mixed. Of 6 pre-Clovis lumps called human by DNA, 3 are confirmed human. Two of the oldest had too little lipid to classify. The three double-confirmed lumps remain. Meadowcroft argues from hearths. White Sands argues from tracks. Paisley argues from the body itself, at one remove.
Why it matters
A date on a human coprolite is as direct as early American evidence gets without dating a bone. If it holds, people were in the Great Basin while the Clovis story still had the first Americans arriving later, and a western stemmed-point tradition is in the running as their toolkit. If the DNA is contamination, the caves go back to being a dry archive of animals and a few younger camps.
A coprolite is fossil dung. Mitochondrial DNA is the genetic material in the cell's energy factories, inherited down the maternal line, useful for placing a person in a broad lineage and not a portrait. A haplogroup is one of those lineages. Radiocarbon years and calendar years differ. The 2008 paper speaks in radiocarbon years, and the 14,525 figure is calendar years from a later compilation.
Photo tour
2 photographs, unedited. On a phone, swipe the row. Choose one to look closely.
What is still unexplained
These sit beside the consensus account, with the same visual weight. None of them is marked solved.
Location and dating
- Location
- Paisley Five Mile Point Caves, above the Summer Lake plain, near Paisley, Lake County, Oregon. Bureau of Land Management land. Several shallow wave-cut shelters, not one deep cavern.
- Period label
- Current consensus — open to revision Human coprolites at 12,300 radiocarbon years before present in the 2008 study, with a later report of an oldest coprolite at 14,525 calendar years. Western Stemmed points continue through Clovis times. The caves also hold much younger material.
- How this dating was done
- Radiocarbon directly on the coprolites, by accelerator mass spectrometry, plus the DNA extracted from them. Stratigraphy is the dry, organic cave dust, checked for rodent mixing. A point found nearby is not the same date unless it is in the same intact layer.
- What could change it
- A coprolite whose DNA, species, and radiocarbon age are published together from a sealed sample a second laboratory can rerun, with the leaching test stated. Several already exist. Another that fails would move the weight.
What is actually there
- Coprolites dated to 12,300 radiocarbon years before present yielded human mtDNA of haplogroups A2 and B2.
- That is more than 1,000 radiocarbon years older than the Clovis dates cited in the 2008 paper.
- A later synthesis gives an oldest coprolite of 14,525 calendar years.
- The excavators name Western Stemmed points as the late ice-age stone tradition, and note how few tools accompany the oldest dung.
- Contamination and leaching were the main objections, and independent laboratory checks are the published reply.
Open questions
| Question | Status |
|---|---|
| Is every human genetic trace in these coprolites from the person who left them? | The founding haplogroups and the direct dates are the strong form of yes. Leaching is why the question stays open at the edges. |
| What did those people hunt and carry, if the points are scarce? | Open. Diet remains in the dung are part of the later research. A toolkit can be elsewhere in the same cave. |
The current narrative
Where publication stands today. It is the best-supported reading, and it is open to revision. It is not a verdict.
The current narrative — open to revision
People in the caves by 12,300 radiocarbon years ago
Human coprolites with founding Native American maternal lineages are directly dated to 12,300 radiocarbon years before present, and some as old as 14,525 calendar years. The DNA is from the people who left the dung, not from later leaching, and the caves are a pre-Clovis site on the strength of that.
What supports this
- Direct radiocarbon dates on the coprolites, not only on nearby charcoal.
- Haplogroups A2 and B2, checked in more than one laboratory.
- Sediments described as stable, with rodent disturbance visible when it occurs.
- A stone tradition, Western Stemmed, in the same late Pleistocene levels.
What pushes back
- Cave DNA leaches, and carnivore dung can carry human traces.
- Few artifacts sit with the oldest coprolites, which is an odd quietness if the cave was a camp.
- The calendar figure of 14,525 and the radiocarbon figure of 12,300 are not the same measurement, and mixing them up makes the site sound more precise than the 2008 paper was.
What would settle it
This is the best-accepted pre-Clovis evidence of its kind in North America, because the date is on a human residue. The leaching objection is why it is not a closed case, and it is weaker than it was before the repeat extractions.
Emerging narratives
Other published readings. Each may be right. None is adopted here unless the evidence carries it.
An emerging narrative
The DNA is later than the dung
The coprolites may be old, even animal, and the human DNA soaked in from later Native American visitors or from the laboratory. The caves are not a 14,000-year-old human site on this evidence alone.
What supports this
- Leaching and contamination are real failure modes for cave genetics.
- A scarce toolkit is what you would also expect if the genetic signal and the occupation do not match.
- Extraordinary genetic claims need the sample history in print, every time.
What pushes back
- Founding haplogroups from blind tests are a strange result for random modern contamination, which would not politely be Pleistocene-aged.
- The carbon date is on the coprolite that yielded the DNA.
- The excavators' sediment study does not describe a churned cave.
What would settle it
Still the right question to ask of any single sample. It is no longer a better account of the whole series than the one the papers defend.
Should the current view be reevaluated?
Consensus holds well
Paisley's centre of gravity is a directly dated human coprolite at 12,300 radiocarbon years, with founding lineages and later laboratory support, and an oldest reported age of 14,525 calendar years. That holds better than most pre-Clovis claims because the person and the date are the same object. Leaching and a thin stone record keep it from being a finished proof.
What drives this
- Coprolites at 12,300 radiocarbon years with haplogroups A2 and B2.
- Independent laboratory checks.
- A reported oldest age of 14,525 calendar years.
- A leaching objection, and few tools with the oldest dung.
This is the museum’s own weighing of the evidence. It is not a visitor vote, and it is separate from the slider.
Weigh it yourself
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If the contested reading is right
What would follow if a reading that is not the consensus turned out to be true, and what could settle it. This explains the stakes. It does not adopt the reading.
The DNA leached in later
Paisley stops being a pre-Clovis anchor. The Western Stemmed points would need their own dates, and the peopling argument would lean harder on White Sands, Meadowcroft, and sites with tools in a layer.
Why it is still worth a test
A sample history that shows human DNA in a coprolite whose other contents are a carnivore's, or a date that splits the dung from the DNA.
Sources
- DNA from pre-Clovis human coprolites in Oregon Science
- Geochronology, archaeological context, and DNA at the Paisley Caves University of Oregon, field report compilation
- Lipids in the Paisley coprolites Science Advances, 2020. Of 18 coprolites called human by DNA, 10 match human lipids, 6 match carnivores, and 1 is mixed. Of 6 pre-Clovis lumps, 3 are confirmed human. Two of the oldest had too little lipid to classify.
Image credits
- A cave mouth at Paisley, above the Summer Lake plain. The dated evidence is not the rock. It is what people left in the dry dust inside.. Bureau of Land Management, Public domain. Shown unedited.
- A specimen the photographer identifies as a human coprolite from the Paisley Caves. The published ages belong to samples of this kind, dated in the laboratory. This frame is not a lab certificate for this particular lump.. Dennis LeRoy Jones, CC BY-SA 4.0. Shown unedited.