The Body Temperature of Crocodiles Is Rising Resulting in Strange Behaviors; Blame the Climate Change
Crocodiles are known for adapting to their life on land and water. These cold-blooded reptiles regulate their body heat in response to their environment which is why, crocodiles are typically spotted basking under the sun to warm up and retreating to cool streams to bring down their body heat during nights. However, in a recent study published in the scientific journal Current Biology, it was disclosed that crocodiles have started changing their behavior for a concerning reason lately.
Kaitlin E. Barham, a doctoral candidate studying crocodile movement and behavior at the University of Queensland, Australia, led the research and revealed how climate change might be pushing the crocodiles to their limits. Particularly in Australia, the estuarine crocodiles are struggling due to global warming. Climate change caused the body temperature of the crocodiles to rise, resulting in their strange behavior. The experts produced a report after studying the behavior of crocodiles in the region for the past 15 years and realized that the average body temperature of the crocodiles had increased significantly.
Their core temperature rose to 32 degrees Celsius and the crocodiles in captivity displayed a dip in their swimming and diving performances. As their bodies got hotter, the reptiles tried to minimize their physical activities to cool themselves off. "A hotter croc has a higher metabolism," Barham told Live Science. "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." Experts monitored 203 estuarine or saltwater crocodiles from 2008 to 2023 at the Steve Irwin Wildlife Reserve in Queensland, tracking their body temperature using acoustic devices implanted under their skin.
Those devices send signals to receivers nearby and other trackers monitor the crocodile's physical condition when they submerged themselves. "The croc would disappear for a few hours, and then come back 1 or 2 degrees Celcius or 1.8 to 3.6 Fahrenheit cooler," Barham explained. While conducting the study, experts recorded almost 6.5 million temperature readings from the crocodiles. The highest body temperature they recorded was increased by 0.55 degrees Celsius. A total of 135 crocodiles showed that their body temperature exceeded 32 degrees Celcius at least once. One of the crocodiles had a consistently high body temperature for more than a month in 2021.
The peak in their body temperature was recorded mostly during the periods of El Nino when warm Pacific currents caused hot and dry spells in Australia. "Every minute that they're up on the bank trying to bring their body temperature down is a minute that they're not spending traveling, reproducing or looking for food," Barham added. "That could result in future indirect effects on their health." The study concluded that crocodiles are susceptible to multi-year fluctuations in ambient temperature, which requires them to undertake concomitant changes in behavior. They are already close to their physiological thermal limit and it is not known how they will cope with the increasing temperature in the future.