Crocodiles are large aquatic reptiles that live throughout the tropics in Asia, Africa, the Americas, and Australia. The first crocodiles appeared approximately 240 million years ago – around the same time as dinosaurs. And while the resilient species did survive the last great extinction, crocodiles might not be climate change-proof after all.
Rising water temperatures could threaten the future of the species. Researchers at the University of Queensland in Australia studied the behavior of crocodiles in three pools heated to different temperatures: 28 degrees Celsius (the region’s current summer water temperature), 31.5 degrees Celsius (water temperature expectations under moderate climate change), and 35 degrees Celsius (the worst case climate change scenario).
Scientists noticed that increased water temperatures resulted in shorter crocodile dives. Essie Rodgers, the lead author of the study, said the submergence time of crocodiles “halved with every 3.5-degree Celsius increase in water temperature.”
Crocodiles submerge themselves for a variety of reasons, including protection, socializing, sleeping, and eating. They can linger up to 30 minutes under water at a time, and spend an average of 11 hours a day submerged.
Crocodiles are also ectothermic – meaning they regulate their body temperature using external elements like the sun. And when they get too hot, crocodiles rely on cooler waters to keep them from overheating.
In order to survive in a changing climate, crocodiles will likely be forced to seek more suitable habitat or face extinction. And while crocodiles survived on this planet for millions of years – unfortunately for them and for us – they seem to have finally met their match.
Photo, posted October 2000, courtesy of Bernard Dupont via Flickr.