Early primates survived in chilly climates not tropical forests

Primates – the group of animals that features monkeys, apes and people – first developed in chilly, seasonal climates round 66 million years in the past, not within the heat tropical forests scientists beforehand believed.

Researchers from the University of Reading used statistical modelling and fossil knowledge to reconstruct historical environments and hint the place the frequent ancestors of all fashionable primates lived. 

The examine, printed at the moment (Tuesday, 5 August) within the journal PNAS, says these first primates probably lived in North America in a chilly local weather with scorching summers and freezing winters, overturning the long-held “warm tropical forest hypothesis” that has lengthy influenced evolutionary biology.

Dr Jorge Avaria-Llautureo, lead creator on the University of Reading, mentioned: “For decades, the idea that primates evolved in warm, tropical forests has gone unquestioned. Our findings flip that narrative entirely. It turns out primates did not emerge from lush jungles – they got here from chilly, seasonal environments within the northern hemisphere.

“Understanding how ancient primates survived climate change helps us think about how living species might respond to modern climate change and environmental changes.”

Primates that might journey far when their native climate modified rapidly have been higher at surviving and having infants that lived to turn out to be new species. 

When primates moved to utterly completely different, extra secure climates, they travelled a lot additional distances – about 561 kilometres on common in comparison with simply 137 kilometres for these staying in related, unstready climates. Early primates might have survived freezing winters by hibernating like bears do at the moment – slowing down their coronary heart charge and sleeping by means of the coldest months to save lots of power. Some small primates nonetheless do that – dwarf lemurs in Madagascar dig themselves underground and sleep for a number of months when it will get too chilly, defending themselves from freezing temperatures below layers of roots and leaves.

Primates did not attain tropical forests till tens of millions of years later. They began in chilly locations, then moved to delicate climates, then to dry desert-like areas, and at last made it to the new, moist jungles we see them in at the moment. When native temperatures or rainfall modified rapidly in any path, primates have been pressured to seek out new properties, which helped create new species.

Püschel, T. A., Meade, A., Baker, J., Nicholson, S. L., & Venditti, C. (2025). The radiation and geographic growth of primates by means of various climates. Proceedings of the National Academy of Sciences, 122(32), e2423833122.