Why was the Cane Toad Brought to Australia?
Scientists warned the farmers not to bring the cane toad to Australia but the farmers didn't listen and brought them in anyway.
Cane Toads are Adapting the the Australian Environment
Australian scientists have recently discovered that the once strictly nocturnal cane toads have started to change their behaviour as they move further into semi-arid parts of the Australian Outback.
Historically cane toads lived in reasonably moist environments and came out to hunt at night, but as they move further into the interior of Australia they have been confronted with dry and hot climate of these areas. Cane toads cannot survive for more than a few days without water, so they have tackled this environmental hurdle by congregating around man-made dams and watering holes constructed by graziers to water their cattle and sheep flocks. By cooling down and rehydrating themselves against the extreme daytime they have found a way to survive the extreme environment.
How the Cane Toad became a Pest
The cane toad has no natural enemies in Australia and lives up to 20 years. A female cane toad can lay up to 40,000 eggs (while the native frogs lay only about 1,000). Most native tadpoles can't live in the same water as the poisonous Cane Toad tadpoles.
The cane toad is highly poisonous. It carries toxin in two large bulging glands on its shoulders (see them in the picture). Native animals that normally feed on native frogs try t o eat the cane toad and die. The poison is so strong that even grasping the toad in their mouths is enough to kill them.
Because they are multiplying so rapidly and because they will eat almost anything that will fit in their mouths they are devastating the native animals, the ground dwelling micro-fauna (small ground creatures) in areas they invade.
What Animal can Kill a Cane Toad?
One of the most interesting killers of cane toads is the Australian crow. This bird has figured out that by flipping the cane toad on its back it can avoid the toad's poison glands. The crow then pecks through the toad's mouth and soft underbelly and eats its insides.
There are a few other Australian creatures that can successfully counter the cane toad. Spiders such as the common wolf spider and Australian tarantula can kills and eat cane toads. Meat ants and water beetles also eat millions of young cane toads and tadpoles each year.