TEMPORAL PATTERNS IN THE DIETARY ECOLOGY OF LATE PLEISTOCENE MAMMALIAN CARNIVORES FROM RANCHO LA BREA
Isotopic results demonstrate that although both carnivore species were feeding within a C3 plant ecosystem throughout the late Pleistocene, their dietary ecologies differed. S. fatalis had a constant average d 13C value through time, but there was a significant decrease in the values of C. dirus at 11ka. The higher d 13C values of C. dirus at 30 and 15 ka cannot yet be explained by currently analyzed prey species. S. fatalis had a constant average d 15N value with low variability, indicating a limited prey base. There was a significant increase in S. fatalis d 15N variability through time possibly reflecting a more diverse prey base at 11 ka. C. dirus had a similar average d 15N value, but with higher variability than that of S. fatalis. This suggests that C. dirus was a generalist and scavenger with a wide prey base. In general, there appears to be a shift in the diet of both species from 15 to 11ka, correlating to both established environmental change and the possible arrival of humans in the area.