Primates Evolved in Cold Climates, Not in Tropical Forests

Photo credit: Andrew Walmsley

When you think of monkeys and apes, and perhaps even our early primate ancestors, you might imagine them surrounded by lush tropical forests. New research challenges this assumption — showing that primates evolved in cold, seasonal climates, not in tropical jungles.

Researchers mapped the geographical locations of early primates with historical climate data — discovering they originated in cold conditions, most likely in North America. Next, they adapted to mild climates and dry desert-like conditions. It took millions of years until primates spread to tropical forests.

The climate is a major evolutionary driving force; species that can adapt are more likely to survive. The climate pushed our ancestors to adapt — those who could travel long distances in response to rapid climate change had better chances of survival. Those less able to move went extinct.

Early primates may have survived freezing temperatures by hibernating: slowing their heart rate and metabolism to save energy. Some primates still do this today, like the dwarf lemur, who digs into the ground and keeps warm beneath a soft layer of plant roots and leaves.

Understanding the evolutionary impact of climate shifts is crucial for primate conservation. When orangutans are restricted to small, fragmented forests, they are unable to migrate, adapt, find food or mates, and ultimately survive. We must protect, connect, and rewild their forest home.

Reference: Jorge Avaria-Llautureo, Thomas A. Püschel, Andrew Meade, and Chris Venditti (2025) “The radiation and geographic expansion of primates through diverse climates” PNAS Vol. 122 | No. 32