Textbooks frequently depict primates as having evolved and dispersed exclusively in warm tropical forests, largely based on fossil evidence found in tropical regions. However, a recent study conducted by researchers at the University of Reading indicates that the earliest primates may have thrived in North America’s cold climate, experiencing hot summers and frozen winters.
Primates have transitioned to historically diverse climates: (a) For all primates, transition between the main climates of temperate (top), arid (left), tropical (bottom), and cold (right). The size of the arrows represents the percentage of phylogenetic branches with each transition. (b) Climate transition of early primates living between 650,780,000 years ago. (c) Climate transition of species that lived between 47.8 and 2303 million years ago. (d) Climate transition of species that have lived from 2,303 million years ago to the present. Image credit: Avaria-llautureo et al. , doi: 10.1073/pnas.2423833122.
In this research, Jorge Avalia Lautulo from the University of Reading and his team harnessed statistical modeling alongside fossil data to reconstruct ancient environments and trace where the common ancestors of modern primates existed.
“For decades, the prevailing belief was that primates evolved within warm tropical forests,” stated Dr. Abaria Lautzleo.
“Our findings dramatically overturn this narrative. We discovered that primates did not originate in the lush jungles but in the cold, seasonal environments of the Northern Hemisphere.”
“Understanding how ancient primates adapted to climate change offers insights into how current species might respond to modern shifts in climate and environment.”
Primates, capable of relocating swiftly in response to rapid weather changes, excelled at reproducing, ensuring that offspring survived to establish new species.
As they migrated, primates moved towards entirely different, more stable climates. On average, those remaining in similarly unstable regions were about 561 km apart.
Early primates might have hibernated through the frozen winters, much like today’s bears, sleeping through the coldest months to slow their heart rates and conserve energy.
Some small primates continue this behavior today; for instance, the dwarf lemur in Madagascar digs underground, sleeping for several months during colder periods, shielded from freezing temperatures by layers of roots and leaves.
It wasn’t until millions of years later that primates reached tropical forests.
They began in cold habitats, gradually migrating through temperate zones, arid desert-like areas, and ultimately arriving at today’s hot, humid jungles.
As local temperatures and precipitation fluctuated drastically, primates were compelled to seek new habitats, which facilitated the development of new species.
“Our research indicates that non-tropical, changing environments exerted strong selective pressures on primates with greater dispersal capabilities, encouraging primate diversification and the eventual colonization of tropical climates millions of years post-origination,” the authors concluded.
Their paper was published on August 5th in Proceedings of the National Academy of Sciences.
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Jorge Avalia Rautreo et al. 2025. Radiation and geographical expansion of primates due to diverse climates. PNAS 122 (32): E2423833122; doi: 10.1073/pnas.2423833122
Source: www.sci.news
