Australasian Science: Australia's authority on science since 1938

Cane Toads Develop Shady Habits

Cane toads in Western Australia have been spotted awake and active during the day in deeply shaded habitats, despite the species usually being nocturnal. However, nearby cane toad populations at more exposed sites have remained active only at night.

“We didn’t expect them to change such a fundamental behaviour, particularly given their nocturnal neighbours were only 4–7 km away,” says Dr Simon Clulow of Macquarie University’s Department of Biological Sciences. “This suggests that cane toads are particularly good at changing their behaviour in response to their environment, something known as behavioural plasticity, which might assist their invasive spread into new environments.”

The research, which was published in Scientific Reports (https://goo.gl/DMDqfB), looked at cane toad populations near the invasion front in WA’s Kimberley region from 2013 to 2015. The toads first arrived at the sites studied in 2012 or 2013.

It’s thought cane toads are nocturnal in Australia to escape northern Australia’s intolerably hot and dry conditions during the dry season. However, this area of the Kimberley is rich in sandstone gorges, some of which are the right size and orientation to the sun to offer cane toads more comfortable shady habitats.

The researchers used remote cameras at eight different locations to monitor toad activity. Cane toads living in gorges with an east–west orientation, and therefore in shadows throughout the day, or narrow gorges were mainly active during the day. Gorges that ran north–south or were wider contained mainly nocturnal toads.

The researchers weren’t able to tell if this was beneficial, but the toads’ ability to change their behaviour in response to their environment is troubling news for managers attempting to control cane toads. “Such behavioural plasticity can help invasive species successfully invade new areas, and does help explain why cane toads have been able to colonise so much of northern Australia since their introduction in 1935,” Clulow says.