Original: Science, 309:287-290 PMID 16002615 Increased aridity during peak glaciation (about 18,000 years ago) may have also contributed to the extinction of the megafauna.
Simplified: Science, 309:287-290 PMID 16002615 Climate change, which made the country much drier during an Ice Age about 18,000 years ago, may have also have led to the extinction of the megafauna.