Saltwater Crocodiles Outlived The Dinosaurs But Climate Change May See Their Demise

20/12/2015 6:14 AM AEDT | Updated 15/07/2016 12:51 PM AEST
Dennis Jones via Getty Images
Kakadu National Park, Northern Territory, Australia, Australasia

Saltwater crocodiles may look like a hardy bunch but new research shows a few degrees of warming could have a devastating impact on their ability to eat and sleep.

The University of Queensland study exposed saltwater crocodiles to three temperatures -- the current summer average at 28C; moderate climate warming at 31.5C; and high climate warming at 35C -- and found slight increases on the norm literally put them in hot water.

“We thought that crocodiles -- like many animals -- would adjust to temperature changes so life continues,” School of Biological Sciences professor Craig Franklin said.

“However, we were surprised to find they had little capacity to compensate for water temperature changes and seemed to be hard-wired to operate at certain temperatures."

The crocs stopped diving as often and for shorter periods, which concerns researchers because they go under to eat, evade predators, socialise and sleep.

“Their submergence times halved with every 3.5C increase in water temperature,” lead author and PhD student Essie Rodgers said.

Franklin said global warming may also mean saltwater crocs would move south.

“It’s likely that if the water is too hot, crocodiles might move to cooler regions, or will seek refuge in deep, cool water pockets to defend their dive times,” Franklin said.

Another study also released this week showed climate change could also stop baby fish from finding a safe haven.

The study by The University of Adelaide looked into the established link between increasing levels of CO2 in the atmosphere and ocean acidification.

Using barramundi hatchlings, the study found acidic water caused neurological issues, stopping them from finding mangroves and other safe places for young hatchlings to hide.

"Baby fish can find those places through ocean noise: snapping shrimps and other creatures produce sounds that the baby fish follow," PhD candidate Tullio Rossi said.

“But when ocean acidity increases due to increased CO2, the neurological pathways in their brain are affected and, instead of heading towards those sounds, they turn tail and swim away.”

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