Crikey! Crocs in the Top End are eating 9 times the amount they did 50 years ago

Embargoed until: Publicly released: 2025-03-12 11:01

Australia; VIC; QLD; NT

Image by Maxi Diaz from Pixabay

Crocs in the Top End are eating nine times the amount they did 50 years ago, and could be helping to control feral pigs and buffalo, according to Australian research, which suggests the predators are having a significant impact on their environment. The researchers looked at the food intakes and the outputs of crocodiles across Northern Australia over a 50 year period, during which the population increased from a few thousand to over 100,000. They found that the crocodile population’s annual prey consumption increased ninefold between 1979 and 2019, and they shifted from eating aquatic prey to more land animals. The researchers say this suggests the crocodiles could be helping put pressure on invasive feral animals such as pigs and Asian water buffalos. The researchers also found that the crocodiles are helping to add nutrients such as nitrogen back into the water.

News release

From: The Royal Society

Quantifying the ecological role of crocodiles: A 50-year review of metabolic requirements and nutrient contributions in northern Australia.

Apex ectotherm predators, like estuarine crocodiles, are thought to impact ecosystems differently from endothermic predators due to lower prey needs. Our study examined changes in prey consumption and nutrient cycling as northern Australia’s crocodile population grew from 1,000 to over 100,000 in 50 years. Consumption increased ninefold since 1979, with a shift towards terrestrial prey. This high crocodile biomass now drives prey consumption rates similar to terrestrial endothermic predators. Crocodiles exert significant top-down pressure on invasive feral ungulates and enhance the transfer of biomass-limiting nutrients (N and P) into nutrient-poor freshwater ecosystems, which may impact these oligotrophic freshwater environments.

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Research The Royal Society, Web page Please link to the article in online versions of your report (the URL will go live after the embargo ends).

Journal/
conference: Proceedings of the Royal Society B

Research:Paper

Organisation/s: Charles Darwin University, Australian Institute of Marine Science (AIMS), Monash University, Griffith University

Funder: This work was supported by the Australian Research Council (Project ID: DP210103369).

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