Ancient Blood Mystery: Scientists Discover Shocking Ingredient Behind 2,000-Year-Old Cliff Paintings
SOUTHERN CHINA — Scientists have uncovered a surprising explanation behind the remarkable durability of the Zuojiang Huashan Rock Art in southern China: ancient artists mixed blood—possibly gathered during childbirth—into their paint.
Despite enduring two millennia of scorching heat, heavy monsoon rains, and typhoons on exposed limestone cliffs, the vibrant red figures created by the ancient Luoyue people (circa 5th century BCE to 2nd century CE) remain vividly visible today.
The Secret to 2,000-Year Durability
According to a study published in the Journal of Archaeological Science, researchers analyzed paint fragments that had naturally fallen from three rock-art sites. Using advanced microscopy, spectroscopy, and protein analysis, they discovered that the pigment was far more than simple paint:
Pigment Base: The red color was derived mainly from local iron-rich clay.
Organic Binder: The pigment was embedded in a lime-based layer containing animal and human blood proteins.
Biomineralization: Proteins in the blood helped form a dense, organic-mineral composite (biomineralized calcium carbonate) that tightly bonded the pigment to the limestone surface.
Links to Childbirth and Fertility Rituals
While the analysis identified blood proteins from cattle and other large herbivores, the most extraordinary finding came from specific human proteins: prolactin-inducible protein and lactotransferrin.
Because these proteins occur in elevated concentrations during late pregnancy and shortly after childbirth, researchers hypothesize that some of the blood may have been collected from women during delivery. This aligns with historic interpretations of Luoyue culture, which placed high spiritual value on imagery associated with fertility and reproduction.
Key Takeaways & Expert Caveats
Minimal Blood Required: The researchers estimate that surprisingly little blood was needed—no more than roughly 8 milliliters per square meter of painted surface.
A Hypothesis, Not Final Proof: Independent experts caution that human protein signals were relatively weak, meaning modern contamination or alternative biological sources cannot be fully ruled out yet.
Regardless of the blood's exact origin, the discovery offers strong scientific evidence that the Luoyue people engineered an unusually advanced biological-mineral binder, preserving their sacred art for thousands of years.
