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Researchers from Charles Darwin University found Top End crocodiles have changed their diet from fish and marine life to wild pigs and buffalo in recent years, a shift biologists believe has significantly boosted crocodile numbers.
CDU Research Associate Dr Mariana Campbell said the diet change could be the reason crocodile populations bounced back so quickly after record lows in the 1970s, when only a few thousand of the predators remained.
“We were surprised to observe such a significant shift in the diet of estuarine crocodiles across the Top End over the past 50 years,” Dr Campbell said.
“Our results show that they have shifted from a marine-estuarine based diet, such as fish, marine turtles, to a more terrestrial-based diet of feral pigs and buffalo.
“A reduction in estuarine prey may have also contributed to the crocodiles’ diet change.”
Scientists analysed crocodile isotopes from bones in museums to the bones of crocodiles around today.
From near extinction, the reptiles are now a protected species with over 100,000 in the wild in the Northern Territory today.
Co-author of the study, CDU Professor of Environment Hamish Campbell said increasing numbers of wild pigs had made crocodile conservation efforts “Australia’s large carnivore success story”.
He said the reduction of feral pig populations, one of Australia’s most destructive pests, is an added bonus of the crocodile’s diet change.
“The research shows that crocodile recovery is having a significant impact on both freshwater and terrestrial food webs in northern Australia,” Professor Campbell said.