New research challenges the widely accepted hypothesis that primates originated and evolved in warm tropical forests. The study, published in the Journal PNAS, finds that in fact, the first primates most likely lived in North America, in a cold climate with hot summers and freezing winters.
Researchers including Dr Thomas Püschel, Associate Professor in Evolutionary Anthropology at the School of Anthropology and Museum Ethnography, University of Oxford and collaborators from the University of Reading used fossil data and statistical modelling to reconstruct ancient climate environments and trace the locations where the common ancestors of modern primates lived. The results suggest that early primates mostly lived in the non-tropical climates of the northern continents.
These findings not only overturn the longstanding narrative that early primates originated in tropical forests, similar to the environments where we find modern primates, but could provide clues to help us understand how the primate common ancestor survived and thrived. It is possible, for example, that early primates survived freezing winters by hibernating, just as dwarf lemurs do today. These small primates dig themselves into the ground for hibernation beneath a soft layer or plant roots and leaves where they are protected from freezing temperatures.
The research also sheds new light on how primates may have spread to new areas and how new species may have evolved. When local temperature or rainfall changed quickly, early primates were forced to find new homes. Those that could travel longer distances to different but more stable climates were more successful, they survived and reproduced, with their descendants going on to diversify into new species. Contrary to the hypothesis that their survival, evolution and spread was dependent on tropical forests it appears that primates started in cold climates, moved to mild climates, then to dry desert-like environments and finally reached the tropical forests where we see them today millions of years later.
Dr Thomas Püschel said:
We’ve long assumed that primates evolved in tropical forests because that’s where most of them live today. But the fossil and climate evidence tells a different story, early primates were more adaptable than we thought, and they likely evolved in much colder, more seasonal environments. By combining fossil data with climate reconstructions and statistical modelling, we were able to trace where primates’ ancestors actually lived, and it wasn’t the tropics. That’s exciting because it opens up entirely new ways of thinking about how primates first evolved and spread across the globe.
Read the research in full:
Avaria-Llautureo, J., Püschel, T. A., Meade, A., Baker, J., Nicholson, S. L., & Venditti, C. (2025). The radiation and geographic expansion of primates through diverse climates. Proceedings of the National Academy of Sciences, 122(32), e2423833122. https://doi.org/10.1073/pnas.2423833122
