Crocodile relatives tracked warm climates for 250 million years, study finds
A UCL-led study of more than 7,000 fossils and records from over 400 living and extinct species found that crocodile relatives generally followed warm climates, spreading towards the poles in warmer periods and retreating towards the tropics as the planet cooled. The researchers’ climate simulations suggest warm refuges near the equator and in the subtropics remained suitable after the asteroid impact 66 million years ago in all but the most extreme scenario.
Bottom line — The researchers say climate was only part of the explanation: smaller bodies, semi-aquatic lifestyles and flexible diets may also have helped crocodile relatives survive.
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UCL researchers found that, around 50 million years ago, crocodile relatives lived in high-latitude regions including Europe and Antarctica.
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In the simulations, a 15% reduction in sunlight erased suitable climates; reductions of 5% or 10% left warm refuges.
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The study authors note two exceptions: one lineage tolerated hotter conditions around 94 million years ago, while an extinct Australasian group adapted to drier conditions about 34 million years ago.
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UCL professor Philip Mannion said roads, farms and cities are making it harder for today’s crocodiles to move towards suitable habitats as the planet warms.