An unexpected behaviour change is being reported in the crocodiles as climate change pushes these reptiles to their limit, a new study has claimed. With increased temperatures due to global warming, the estuarine crocodiles in Australia are struggling, meaning they are diving less and cooling themselves off more.
Crocodiles are ectothermic or cold-blooded animals, meaning they rely on external environments to regulate their body temperature. They usually thrive in warm climates, basking in the sun or cooling off in water as needed. But as global temperatures climb, the balance is tipping.
As per the study published in the journal Current Biology, earlier this month, the average body temperature of crocodiles had increased by a small but significant amount. In total, data from 203 crocodiles revealed that, since 2008, the highest crocodile body temperatures have risen by 0.55C.
"As ambient temperatures rose, crocodiles experienced more days close to critical thermal limits (32C-33C), at which temperatures the duration of dives was reduced and the prevalence of active cooling behavior was elevated," the study highlighted.
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Changed behaviour
The overheating is not just a comfort issue for one of the oldest reptiles on the planet. It is altering their routines. Researchers observed that crocodiles were less active during the hottest periods, reducing their hunting and feeding time.
"A hotter croc has a higher metabolism. Higher metabolism means burning oxygen more rapidly. Lab research found that they just couldn't hold their breath for as long. It would take them a bit longer to recover at the surface," said lead author Kaitlin Barham.
In extreme cases, some abandoned sunlit basking areas entirely, retreating to deeper, cooler waters. This shift could impact their growth and reproduction, as prolonged heat stress hampers metabolism and energy reserves.
Of the 203 crocodiles examined, 65 per cent exceeded the 32-degree body temperature limit at least once, 41 per cent exceeded 33 degrees and 22 per cent exceeded 34 degrees.
The researchers suggested that if climate change continues, the crocodiles may need to cool more frequently or potentially seek newer pastures such as the southern region of Australia which is relatively cooler
