Analysis of zinc isotopes in ancient tooth enamel shows no link to carbon or oxygen isotopes that reflect diet type or climate conditions, meaning zinc isotopes can reliably indicate an organism's...
Mechanism
Synthesis from 1 study
Animals that eat plants end up with more of a heavier form of zinc in their teeth, while meat-eaters have less of it because their prey already lost some. This difference gets locked into teeth as they form and doesn’t change after death, even if the animal lived in a hot or wet place or ate...
Most probable mechanism
When animals eat plants, their bodies retain more of the heavier zinc isotope, making their teeth have a higher ratio of that isotope. When animals eat meat, they get zinc that already lost some of the heavier isotope, so their teeth have a lower ratio. This difference stays locked in tooth enamel as it forms and doesn’t change after death, even if the animal lived in a hot, wet environment or ate different kinds of plants. That’s why scientists can tell if an animal was a plant-eater, meat-eater, or both, just by measuring the zinc in its teeth — without being misled by climate or plant type.
Plants absorb zinc from soil and preferentially take up heavier zinc isotopes during root uptake, while lighter isotopes move more readily toward leaves and edible parts.
Herbivores consume plant material rich in heavier zinc isotopes, and their bodies incorporate this isotopic signature into developing tooth enamel with minimal alteration during metabolism.
Carnivores consume muscle tissue from herbivores, which has already been depleted in heavier zinc isotopes due to metabolic retention in the prey, resulting in lower zinc isotope ratios in their own tissues.
Zinc is incorporated into the mineral structure of tooth enamel during formation, and this isotopic signature is chemically stable and resistant to postmortem alteration by environmental factors such as temperature, humidity, or soil chemistry.
Evidence from Studies
Supporting (1)
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Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information
Contradicting (0)
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