Extinct Pleistocene carnivores were diurnal and highly active

There is much contention over the causes and correlates of megafaunal extinctions at the end of the Pleistocene. A major role for human impact such as hunting has been discussed widely. If correct, the overkill hypothesis explains not only why large mammals in general were highly prone to extinction but suggests that extinction may have been selective within large mammals. Among other things, it has been argued that extinct large mammals tended to be large and have small brains. Here we test these hypotheses using a comprehensive global dataset of 22 ecological and life history traits mapped to 120 living and 14 extinct carnivore species. The data document occurrences within 260 distinct fossil assemblages that span the Late Pleistocene and Holocene. To address collinearity and phylogenetic autocorrelation, we first perform least-squares orthogonalisation of the predictor variables and then use phylogenetic comparative methods to carry out regressions. Only basal metabolic rate and diurnality are robust predictors of extinction, even after accounting for phylogenetic and trait uncertainty. Furthermore, we show that living carnivores with high metabolic rates are more likely to be threatened and address the implications for conservation and the current extinction crisis.