The Wet Tropics of Queensland is home to more than 50 native frog species, including 22 species found nowhere else in Australia.  

But there's another amphibian that has made itself right at home here - the notorious, ecosystem-damaging cane toad. 

Cane toads (Rhinella marina) are originally from South America. In 1935, 102 individuals were introduced to Australia by the Queensland government as a way to control cane beetles in sugar cane plantations (it didn't work). Without any natural predators, the cane toads thrived, and their range slowly spread to urban areas, coastal dunes, woodlands, and freshwater wetlands. 

They also found their way into the Daintree lowlands (between the Daintree River and Cape Tribulation). By 1937, the population had increased to 62,000, and now they have reached estimates of 200 million or more.

Cane Toad

One female can lay up to 90,000 eggs a year. Only one in 200 eggs will survive, however, individual cane toads can live for up to 16 years. They are now well established in Queensland and New South Wales and are migrating through the Northern Territory at a rate of 40 km a year. A few have also reached Western Australia, hitching rides on travelling vehicles.

As an introduced exotic species, cane toads are a serious problem because they poison and kill their would-be predators. They also eat small reptiles, insects and other amphibians, and displace native species as they compete for food and resources to survive. The toads' poisonous tadpoles and eggs also kill aquatic creatures.

However, nature is fighting back. Not only are a number of birds and animals finding ways to safely eat cane toads, they are becoming infested with a range of parasites. One, lungworm, came with them, but a number hopped from native frogs to the new host. Any scrawny little cane toads you see are probably loaded with parasites.

Cane toad appearance:

It's important to know the difference between a native frog species and a cane toad. Here's what you need to know. They are;

  • Coloured brown, olive-brown or reddish 
  • Have thick, leathery skin with warts
  • A visor or awning over each eye
  • A bony ridge that extends from eyes to nose
  • Small feet, with claw-like un-webbed digits to dig
  • Two large toxin-filled parotid glands behind the ears
  • They may appear dry, are heavily built, and can reach up to 20 centimetres long
  • Have a very loud and distinctive mating call, a bit like a musical motorboat (produced by the male).

Controlling cane toads

Cane toads will find a moist, cool place to hide during the day and prefer urbanised areas, around houses and gardens with mown lawns. This is because they find it difficult to move through tall vegetation as they are not very good at climbing and jumping. Like most amphibians, they need water to breed. However, the soil in much of the Daintree Lowlands is sandy, and water doesn’t pool after rain, depriving the toads of suitable places for their eggs to develop. However – your ornamental pond or pools of water in your garden just might be an ideal breeding site! 

To reduce the number of cane toads, residents and land managers in the Daintree Lowlands can do a few simple things:

  • Remove places they can breed - still water, puddles, etc
  • Place pet food out of reach
  • Reduce lawns and increase rainforest habitat
  • Cane toads, unlike our native frogs, lay their eggs in long gelatinous strings, which are easy to recognise and scoop out (just lay them somewhere where they will dry out).

“Cane toads can be collected and removed by hand. Traps and barrier fencing can be used to contain them but vary in effectiveness. According to recent research by the University of Sydney, refrigeration followed by freezing is the most efficient, effective and humane method of cane toad euthanasia”, explains the NSW Department of Planning and Environment.

Two highly recommended videos:

Cane Toads, an Unnatural History

Cane Toads, The Conquest

Do you have more information about cane toads in the Daintree Lowlands?

Please, share your knowledge of cane toads in the Daintree Lowland Rainforest so that we can improve our understanding of the issue. Email us at [email protected]

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