C and N stable isotope measurements on Eurasian fossil mammals, 40 000 to 10 000 years BP: Herbivore physiologies and palaeoenvironmental reconstruction

Seventy-seven specimens of fossil (Upper Pleistocene-Early Holocene) woolly mammoth, reindeer, deer and bison from 17 different locations in Eurasia have been measured for the nitrogen and carbon stable isotope composition of their collagen and for the carbon stable isotope composition of bioapatite. The aim was: (1) to check the existence of differences in N and C isotope ratios between and within different herbivore species (mainly between mammoth and reindeer); (2) to discuss these data in terms of animal physiology, temporal and spatial distribution of animals and effects of climatic changes; and (3) to obtain further information about the environmental changes that occurred in that area during the period considered. A geographical variation from south-west to north-east in the delta N-15 and/or delta C-13 values of collagen and bioapatite for all the herbivore species is apparent, the most negative delta C-13 values and the most positive delta N-15 values bring located in the north-eastern area. This was probably due to a different temperature and water stress on animals and plants and to a different plant availability. The differences in C-13/C-12 and N-15/N-14 isotope ratios among species are mainly related to different food intake and different metabolic pathways. It seems also that the diet of mammoths from north-eastern Siberia was higher in protein content compared with that of mammoths from the Russian Plain. From this study, it is clear that there was a rapid and important change in the amount of precipitation soon after the last glacial maximum; the rainfall conditions around 40 000 and 30 000 years BP were probably similar to those existing around 10 000 years BP, though lower than those existing after the glacial maximum. (C) 2000 Elsevier Science B.V. All rights reserved.