Table 2. δ¹³C of atmospheric CO₂ (δ¹³C_atmCO2) and mammalian enamel δ¹³C (δ¹³C_enamel) cut-off values between different environments in the late Miocene, Pliocene and Pleistocene.

	Late Miocene	Pliocene	Pleistocene
δ13CatmCO2	−6.2	−6.3	−6.5
δ13Cenamel closed canopy forest	< −14.2	< −14.3	< −14.5
δ13Cenamel woodland to woodland-mesic C3 grassland	−14.2 to −9.2	−14.3 to −9.3	−14.5 to −9.5
δ13Cenamel open woodland-xeric C3 grassland	−9.2 to −6.2	−9.3 to −6.3	−9.5 to −6.5
δ13Cenamel mixed C3–C4 grassland	−6.2 to −1.2	−6.3 to −1.3	−6.5 to −1.5
δ13Cenamel C4 grassland	> −1.2	> −1.3	> −1.5

δ¹³C_atmCO2 values are from Tipple et al. [40], δ¹³C_enamel have been calculated using a diet-to-enamel fractionation of 14.1‰ from Cerling & Harris [39]. All values are in ‰ VPDB.