Conservationists battling the toads say they have noticed a marked change in the animals’ behaviour and size as the toad front moves west and say to creatures now retreat from headlights, surf down rivers on debris and are showing an increased ability to survive when compared to their Queensland ancestors.
Field coordinator with Kimberley Toad Busters Ben Scott-Virtue said volunteers were reporting “Rambo” style toads that appeared to be leading the feral invasion.
He said the Rambo toads were hopping ahead of the toad front, finding suitable habitats and then calling in the nearest “wave” of the breeding population.
“The females are often, on average, as large as 17.5cm from snout to tail bone and the males around 14 to 15cm. There back legs are between 2 to 4cm longer than their bodies and the pads on their feet are blackened and calloused from constant travelling,” Scott-Virtue said.
He said the colonising toads were being found up to 30km ahead of the toad front and explorer toads had been observed in dry landscapes following cow trails and using moist cow dung to move between water holes.
Volunteers with the group had observed toads riding on logs and other debris in swollen rivers and staying underwater for up to 90 minutes.
The latest observations from group members contradicts earlier evidence that suggested the toads moved only a maximum of 30km a year, did not swim well in fast flowing rivers and had a low tolerance to salt.
Scott-Virtue said it appeared the creatures were evolving into ‘super toads’ and had even learned to move away from headlights that had previously stunned them.
As a result the creatures were becoming harder to hunt and harder to stop. He said all of the toad-busting volunteers were noticing the toads new response to lights.
“Not only are these front-line toads moving an average of 80 kilometers a year, they were larger, extraordinarily resilient to the saline conditions of some of the rivers they were crossing and that the breeding survival rate is in the vicinity of 75 per cent to 85 per cent.”