You are what you eat:
Using isotopes to work out the diet of extinct animals
C3 and C4 plants
carbon isotopes in distinctly different ways and it is this feature which makes them suitable for
By studying the carbon isotopes in animal/human bones or teeth the diet of the living animal can be extrapolated from the carbon 13 to carbon 12 ratio. The scientific way of writing this is 13C /12C. The 13C /12C ratio of fossil bones or teeth thus reflect the diet of an animal or human. If a sample has a relatively high ratio of 13C /12C, it means the animal ate a diet rich in C4 plants. If the animal is a carnivore it would indicate that they ate animals which were in turn eating the C4 plants.