The Claim
Zinc isotope ratios (δ66Zn) in fossil tooth enamel from Late Pleistocene mammals in Tam Hay Marklot cave, Laos, exhibit a consistent pattern across trophic levels, with carnivores showing the lowest mean values (0.09‰), omnivores intermediate values (0.41‰), and herbivores the highest values (0.68‰), resulting in a carnivore-herbivore spacing of +0.60‰, demonstrating that zinc isotopes in bioapatite can preserve dietary information over tens of thousands of years under tropical conditions where collagen is degraded.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Analysis of zinc isotopes in fossilized teeth from ancient mammals in Laos reveals a predictable pattern: meat-eating animals have lower zinc isotope values than plant-eating animals, with herbivores showing the highest values. This pattern persists even after tens of thousands of years, indicating that zinc isotopes in tooth enamel can record dietary habits when other biological markers like collagen have disappeared.
See the scientific wording
Zinc isotope ratios (δ66Zn) in fossil tooth enamel from Late Pleistocene mammals in Tam Hay Marklot cave, Laos, show a consistent trophic-level pattern: carnivores exhibit the lowest values (mean: 0.09‰), omnivores intermediate values (mean: 0.41‰), and herbivores the highest values (mean: 0.68‰), with a carnivore-herbivore spacing of +0.60‰, indicating that zinc isotopes in bioapatite can preserve dietary information over tens of thousands of years under tropical conditions where collagen is degraded.
Plants take up more of the heavier zinc isotope from the soil, so animals that eat only plants end up with higher levels of this heavier zinc in their teeth. Animals that eat other animals get zinc that has already been lightened by the animals they consumed, so their teeth have less of the heavy zinc. This difference gets locked into tooth enamel as it forms and stays unchanged for tens of thousands of years, even in hot, wet environments where other body parts decay.
What the research says
1 studyScientists found that the zinc in ancient animal teeth changes based on what they ate—meat-eaters have less of a certain zinc type, plant-eaters have more—and this pattern stayed intact for over 10,000 years even in hot, humid caves where other clues rot away.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
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