Our primate ancestors evolved in the cold--not the tropics [View all]

August 24, 2025

by Jason Gilchrist, The Conversation
edited by Gaby Clark, reviewed by Alexander Pol



Primates historically transitioned across diverse climates. Credit: Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2423833122


Most people imagine our early primate ancestors swinging through lush tropical forests. But new research shows that they were braving the cold.

As an ecologist who has studied chimpanzees and lemurs in the field in Uganda and Madagascar, I am fascinated by the environments that shaped our primate ancestors. These new findings overturn decades of assumptions about how—and where—our lineage began.

The question of our own evolution is of fundamental importance to understanding who we are. The same forces that shaped our ancestors also shape us, and will shape our future.

The climate has always been a major factor driving ecological and evolutionary change: which species survive, which adapt and which disappear. And as the planet warms, lessons from the past are more relevant than ever.

The cold truth
The new scientific study, by Jorge Avaria-Llautureo of the University of Reading and other researchers, maps the geographic origins of our primate ancestors and the historical climate at those locations. The results are surprising: rather than evolving in warm tropical environments as scientists previously thought, it seems early primates lived in cold and dry regions.

These environmental challenges are likely to have been crucial in pushing our ancestors to adapt, evolve and spread to other regions. It took millions of years before primates colonized the tropics, the study shows. Warmer global temperatures don't seem to have sped up the spread or evolution of primates into new species. However, rapid changes between dry and wet climates did drive evolutionary change.

More:
https://phys.org/news/2025-08-primate-ancestors-evolved-cold-tropics.html