For decades, primates have been cast as children of the rainforest. Fossil-rich tropical soils and the distribution of living species reinforced the notion that the lineage leading to Homo sapiens arose beneath dense canopies of green. Yet a new study in PNAS1 suggests a very different picture. The first primates did not emerge in sultry forests but in colder, seasonal environments where adaptation to scarcity and temperature swings was essential for survival.
