Crocodile Ancestors Survived Extinction by Chasing Warmth
A study in Science Advances links crocodilian survival through mass extinctions to a long-standing preference for warm climates.
Updated on Nov. 3, 2026 in Environmental
A new study in the journal Science Advances proposes that the ancestors of modern crocodiles survived the dinosaur-ending extinction partly because of their preference for warm climates. The crocodilian lineage, which first appeared around 250 million years ago, has endured multiple mass extinctions, including two of Earth's largest.
Why it matters
The findings suggest that climate preference, rather than size or diet alone, may determine which species persist through extinction events. As modern species face ongoing environmental change, the study indicates they may need room to move as the planet warms.
Researchers estimate up to 10 percent of sunlight was blocked after the Chicxulub impact, a model-based figure drawn from the study's paleoclimate reconstruction. Exactly how many equatorial refuges persisted and for how long remains unspecified in the available findings.
The players
Science Advances
A peer-reviewed open-access journal published by the American Association for the Advancement of Science, which released the study.
The details
Crocodile ancestors repeatedly spread toward the poles during warmer phases of Earth's history and returned to the equator when temperatures cooled. Researchers' models indicate that certain equatorial regions likely stayed suitable for ancient crocodiles even after the Chicxulub impact, which also triggered continent-wide wildfires in North America and tsunamis along coastlines worldwide.
Timeline
Around 250 million years ago: the crocodilian lineage first appeared.
Around 66 million years ago: the Chicxulub impact and mass extinction killed the dinosaurs.
Around 34 million years ago: cooling during the Eocene-Oligocene transition pushed crocodiles back into tropical pockets.
Big Picture
The study extends the historical record of the Chicxulub impact and the K-Pg mass extinction around 66 million years ago by explaining why the crocodilian lineage survived when the dinosaurs did not. It also reframes survival at that boundary as partly a matter of climate tolerance rather than body size alone.
Understanding which climates species have historically tolerated can help readers interpret how today's wildlife may fare as temperatures rise. The findings underscore that habitat access, not only physical traits, can determine whether a species endures environmental upheaval.
The takeaway
Species that can move toward suitable climates have historically had a better chance of surviving extinction events. Protecting connected habitats may matter as much as protecting individual populations today.
Further reading
For broader context on how species respond to shifting climates, explore our Environmental coverage.
