The histories of six large herbivores--the woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox--are linked with climate fluctuations and human activity, especially at the end of the last ice age, scientists find in a new report.

Research led by evolutionary biologist Eske Willerslev of the Centre for GeoGenetics at the University of Copenhagen along with an international team of paleontologists, geologists, geneticists and climate modelers suggests early humans and changing climate were responsible for the extinction of some cold-adapted animals, and the near-extinction of others.

The journal Nature published the results of the study this week. It was the first to use genetic, archaeological and climate data to infer the population history of large-bodied ice age mammals.

"The combination of approaches in this study--including the most modern molecular tools and painstaking fieldwork--sheds a powerful light on the complex interactions of humans, ecosystems and climate," said Hedy Edmonds, arctic natural sciences program director in the National Science Foundation's (NSF) Office of Polar Programs, Division of Arctic Sciences.

The results carry a message about the possible fates of living mammals as Earth continues to heat up.

"Our findings put a final end to single-cause theories of these extinctions," said Willerslev.

"Our data suggest care should be taken in making generalizations regarding past and present species extinctions," he said. "The relative impacts of climate change and human encroachment on species extinctions really depend on which species we're looking at."

"We couldn't pinpoint what patterns characterize extinct species, despite the large and varying amount of data analyzed," said scientist Eline Lorenzen of the University of Copenhagen, the first author of the paper.

"This suggests that it will be challenging for experts to predict how existing mammals will respond to future global climate change--to predict ...