Mighter than the croc: cane toads are linked to a major reduction in crocodile numbers in the VRD. (Reuters: David Gray)
Researchers from the University of Sydney have found that cane toads have caused a 75 per cent drop in freshwater crocodile numbers in the Northern Territory's Victoria River District (VRD).
The researchers say this is first time that extensive research has confirmed anecdotal reports about the introduced pests' effect on the native predator.
Researcher Doctor Mike Letnic, says they studied crocodile populations before and after the cane toad arrived in the district.
He says the worst damage was in the arid areas during the dry season.
"The rivers are essentially an oasis and the crocodiles live in the river, but the landscape is dry and during the dry season the cane toads congregate on the edge of the water where they encounter the crocodiles.
"They turn the table on the predator."
He says freshwater crocs are more susceptible to the pest than their saltwater cousins.
"Saltwater crocodiles appear to be more resistant to the toxin than the freshwater crocodiles and the reason for that is probably because saltwater crocodiles occur throughout southern Asia where some toad species also exist, so it's likely that the saltwater crocodiles evolved with species similar to cane toads."
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