For a typical meta-analysis, researchers mine the literature for dates associated with now-extinct megafauna, as well as for estimates of when humans arrived at a particular region (on the basis of archaeological and other data). In some cases, they then combine these records with global-scale palaeoclimate data, such as those obtained from ice cores collected from the Arctic. By mapping correlations between events, investigators try to identify the dominant factor driving species losses.
In March, the last male northern white rhinoceros died. The sub-species joins a long list of large land animals that have gone extinct over the past 100,000 years.