Dietary flexibility helped bears and wolves survive after ice age



Washington: A new study led by researchers at the University of California, Santa Cruz, suggests that dietary flexibility may have been an important factor giving wolves and bears an edge over saber-toothed cats and cave lions.

"We found that dietary flexibility was strongly species-specific, and that large cats were relatively inflexible predators compared to wolves and bears," Justin Yeakel, first author of a paper said.

"This is a key observation, as large cats have suffered severe range contractions since the last glacial maximum, whereas wolves and bears have ranges that remain similar to their Pleistocene ranges," he said.

Yeakel, now a postdoctoral researcher at Simon Fraser University in British Columbia, worked on the study as a graduate student at UC Santa Cruz with coauthor Paul Koch, professor of Earth and planetary sciences at UCSC.

The researchers based their findings on an analysis of stable isotope ratios, chemical traces in fossil bones that can be used to reconstruct an animal's diet.

They used previously published stable isotope datasets to reconstruct predator-prey interactions at six sites located from Alaska to Western Europe.

The sites covered a range of time periods before, during and after the last glacial maximum, the period around 20 to 25 thousand years ago when the ice sheets reached their greatest extent.

The study found that the diets of the large cats were similar in different locations, especially in the post-glacial period.

Wolves and bears, in contrast, ate different things in different locations.

The findings have been published in the Proceedings of the Royal Society B.

ANI