Skip to menu Skip to content Skip to footer
News

Hot crocs show impacts of a warming climate

13 February 2025
a crocodile moves away on a sandy bank
A crocodile wearing a satellite tracker by the Wenlock River, Qld. Image: Australia Zoo

Crocodiles in northern Australia are heating up as the climate warms, with higher body temperatures changing their behaviour.

Research led by The University of Queensland’s School of the Environment analysed 15 years of information from sensors and trackers on 203 wild crocodiles on the Wenlock and Ducie rivers on Cape York Peninsula.

PhD candidate Kaitlin Barham said the data revealed crocodiles were spending more time at or close to their critical thermal limit of 32-33°C, when behavioural performance decreases.

“As ectotherms crocodiles can’t regulate their own temperature like birds and mammals, so as their environment is becoming warmer the animals in our study are also getting hotter and needing to spend more time on cooling behaviours,” Ms Barham said.

“But if their time and energy is dominated by the need to stay cool, activity necessary for hunting, keeping safe from predators or reproducing is reduced.”

Researchers check the temperature of a crocodile. Image: Australia Zoo. 

Researchers check the temperature of a crocodile. Image: Australia Zoo. 

Since 2008 the temperature peaks experienced by the crocodiles in the study have increased by 0.5°C, and their median body temperature has increased by 0.11°C.

The Northern Australia Climate Program reports the region’s mean temperatures are increasing 0.05 - 0.2°C per decade.

Forty-five of the crocodiles in the study experienced body temperatures above 34°C at least once.

Co-author Professor Craig Franklin said high body temperatures were recorded even while the crocodiles were actively trying to stay cool.

“When they’re above 32-33°C, a crocodile’s diving and swimming performance is impacted,” Professor Franklin said.

“Hotter crocodiles don’t dive for as long which is concerning because as ambush hunters, they need to wait underwater holding their breath for a wallaby or feral pig to come past.

“The next step in our research will be to look at what impacts behaviour change related to higher body temperatures may be having on the overall health of the crocodile population.”

This long-term research project has been carried out in collaboration with crocodile experts from Australia Zoo and based from the Steve Irwin Wildlife Reserve.  

The research has been published in Current Biology.

Media assets

Images available via Dropbox

 

Related articles

Three researchers wearing blue protective lab gowns stand among rows of potted chickpea plants inside a controlled-environment plant research facility.

Turning up the heat on chickpea yield

A University of Queensland study has outlined a practical pathway for accelerating the development of heat adapted chickpeas using data from new ‘omic’ technologies. PhD candidate Callum Jamie said the suite of technologies offered tremendous opportunities to understand how a complex trait like heat tolerance works. “The narrow genetic diversity in the elite chickpea gene pool has limited conventional breeding’s effectiveness for stress tolerance,” Mr Jamie said. “These technologies have improved our capacity to dissect trait architecture and phenotype secondary traits but their use in chickpeas has been limited.” The technologies include genomics, epigenomics, transcriptomics, proteomics, metabolomics, phenomics and enviromics, and help provide a comprehensive picture of biological systems. Epigenomics helps understand what controls gene activity; transcriptomics considers gene expression; proteomics protein production; metabolomics looks at biochemical processes; phenomics observes traits; and enviromics considers environmental factors influencing outcomes. Mr Jamie said previous studies had focused on just 1 to 2 -omic datasets, a small number of genotypes, and single tissues. This has meant it was hard to infer what results meant for trait architecture and mechanisms and the ability to extrapolate the information to breeding populations was limited. There have also been challenges around cost, scalability and integrating very different types of data to make the technologies useful. To overcome the hurdles, Mr Jamie’s research at the Queensland Alliance for Agriculture and Food Innovation has resulted in a proposed staged approach. It would start with genomic prediction and phenotyping, before adding -omic layers as costs fall and unknowns were resolved. “These technologies are novel and we still don’t know which information provides added value and how best to integrate all of this data to achieve an outcome,” Mr Jamie said. His PhD is supported by the Grains Research and Development Corporation (GRDC) and the International Research Training Group (IRTG) Accelerating Crop Genetic Gain and is aligned to a project which aims to fast-track the development of chickpea varieties adapted to high temperatures. Project leader Dr Millicent Smith said heat stress causes severe yield implications through flower and pod loss, reduced pollen viability and impaired grain filling. “Late sown chickpea is particularly in the firing line across most of Australia's crop in southern Queensland and northern New South Wales,” Dr Smith said. “We want to ensure that Australian growers maintain their competitive edge. “New varieties with improved genetics to cope with heat stress are essential for the future. “This work, suggesting a staged approach to utilising the new -omic technologies, is an exciting frontier.” The research was published by Food and Energy Security. Callum Jamie’s PhD is supported by the Grains Research and Development Corporation (GRDC) and the International Research Training Group (IRTG) Accelerating Crop Genetic Gain.
15 October 2026
Close-up photograph of a red-bellied black snake coiled across pale, weathered wood. The snake has glossy black scales on its back and vivid red coloration along its sides and underside. The image highlights the texture of the scales and the contrast between the dark body and the light wood background.
Analysis

Deadly fungi are harming Australia’s wild reptiles. This is how to stop the spread

With spring underway and the weather warming, reptiles are on the move in suburbs, parks and bushland across Australia. Snake catchers and wildlife carers are responding to calls for help, and reptile enthusiasts – known as “herpers” – are heading outdoors in search of their next sighting.
13 October 2026

Media contact

Subscribe to UQ News

Get the latest from our newsroom.