During the past 100,000 years, many of Earth's largest animals — including ground sloths, mammoths, woolly rhinos and sabre-toothed cats — became extinct. Scientists have debated why for decades, with climate change and hunting by humans the chief suspects. Graham Prescott, David Williams and their group at the University of Cambridge, UK, have created a model of unprecedented geographical breadth — and concluded that it took both factors to seal the beasts' fate.

The researchers modelled extinctions in North America, South America, Palaeoarctic Eurasia, Australia and New Zealand, running simulations with climate data from ice cores and thousands of plausible combinations of human-arrival and species-extinction times, reflecting the large uncertainty in both these estimates. The recipe that best predicted the pattern of extinctions included both climatic and human ingredients.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1113875109 (2012)