A new study has revealed that climate change is pushing estuarine crocodiles in Australia to their limits, forcing them to change their behavior in response to rising temperatures. The research, published in Current Biology, suggests that higher temperatures are reducing the reptiles’ diving ability and increasing their need to cool off.
Crocodiles Struggling in the Heat
Crocodiles are ectothermic (cold-blooded) animals, meaning they rely on external environments to regulate their body temperature. While they usually thrive in warm climates, rising global temperatures are pushing them closer to dangerous thermal limits.
Researchers analyzed 203 crocodiles and found that since 2008, their highest body temperatures have risen by 0.55°C. The study noted that many of these crocodiles are now experiencing temperatures close to their critical thermal threshold (32°C-33°C) causing noticeable changes in their behavior.
Impact on Activity and Hunting
The study found that crocodiles are becoming less active during the hottest periods, reducing their hunting and feeding time.
“A hotter croc has a higher metabolism, meaning it burns oxygen more rapidly. Lab research found that they couldn’t hold their breath as long and took longer to recover at the surface,” explained lead author Kaitlin Barham.
In extreme cases, some crocodiles abandoned sunlit basking areas altogether, retreating to deeper, cooler waters. This shift could affect their growth, reproduction, and survival, as prolonged heat stress depletes their energy reserves.
Potential Migration to Cooler Regions
Out of the 203 crocodiles studied:
- 65% exceeded 32°C at least once
- 41% exceeded 33°C
- 22% exceeded 34°C
If global temperatures continue to rise, researchers suggest that crocodiles may need to cool off more frequently or even migrate to cooler regions, such as southern Australia.
This study highlights yet another way in which climate change is disrupting ecosystems, affecting even some of the most resilient species on Earth.