One of Australia's most famous and successful pests. An invasive import that like many was deliberately released, this one into Queensland back in 1935 from where it spread rapidly and today is found right across the top of Australia and well into northern WA. These toads are invasive in other places as well, as the story above tells. They are very, very poisonous and many native species from crocs to snakes and eagles to quolls are found dead with a toad still in their mouths.
Once away from endemic range without their natural predators they can breed uncontrolled and populations often explode. Their size alone means they can eat most other species and as prolific egg layers they overwhelm in numbers with highly mobile young toads once they metamorphose from the larval (tadpole) stage. Estimates are of 10-55km rate of territory expansion per year for the species in Australia.
Averaging 10-15cm in length specimens can reach over 38cm and weigh up to 2.5kg. Lifespan 10-15 years in the wild but up to around 35 years in captivity. A female can lay up to 25,000 eggs twice a year, giving you an idea of how hard it is to control them. Preferring fresh water they are tolerant of salty water with around 15% salt content hence 'Marine toad' being another common name for this large amphibian.
Diet wise – if it moves they will try to eat it - bugs, spiders, small rodents reptiles and amphibians are all consumed. Unusually for amphibians they will also eat dead or static food so carrion and even dried cat foods will be taken.
Natural predators (in South America) include, Black rat (Rattus rattus), Whistling Kite (Haliastur sphenurus), Broad snouted Caiman (Caiman latirostris). In Australia some freshwater crocs, crows and tawny frogmouths are apparently eating the non toxic parts of their bodies.
Uses for Cane toads include:
- Scientists are using them for anti cancer treatments;
- Bufotenin, an active ingredient of the poison, has also been used in Japan as an aphrodisiac and a hair restorer, and in China for cardiac surgery to lower the heart rates of patients;
- Some native South/Central American peoples will use them in black magic ceremonies;
- In Australia stuffed as souvenirs and as leather goods and as a liquid fertilizer from pulverised cane toad carcasses;
- They are skewered or roasted in several countries;
- The collected toxin tipping arrow/darts in South America;
- In Peru as a food source once the poison glands are removed;
- I have kept them as pets (in UK). They tame well.
Two documentaries about Cane toads in Australia can be watched on Youtube:
Cane Toads the Conquest (2010)
Cane Toads: An Unnatural History (1988)