What damage did the cane toad do to native species in Australia?

Answer 1

It causes problems for humans as the poisons from a cane toad can give us intense pain, temporary blindness and inflammation.

And for pets it can affect them as well, signs are;

-profuse salivation -twitching -vomiting -shallow breathing and collapse of the hind legs and the pet may fall into cardiac arrest within 15 minutes.

Further information:

Cane toads have become an ecological disaster in Australia, and other places to which they have been introduced. They eat the native wildlife, but have no natural predators. Cane toads eat native frog species, as well as other small birds and mammals, and they compete directly with native frogs and other species for food. Many native frog species are at risk of extinction as a result of the cane toad population.

The only animals that have worked out how to eat them safely are crows, which flip the toads over and eat the soft underbelly, where there are no poison glands. Northern quolls have suffered huge population losses because habitat loss and the resultant drop in food sources has driven them to try to eat the cane toad, which has, of course, poisoned these mammals. Any native animal that normally eats frogs will be poisoned by the cane toad.

Cane toads are also continuing to spread south. They are remarkably adaptable creatures, and seem to be becoming hardier, adapting to a wide variety of habitats and climate conditions. They also breed prolifically, and wherever they populate, they push out the native species.

Answer 2

Cane toads out-compete native species. They are super-survivors; they reproduce quickly, mature quickly, and they will eat any organism that is smaller than itself (Sometimes a small mammal has been found in the stomach of a cane toad). But importantly, cane toads don't have efficient predators in Australia because their skin is toxic. Native snakes and birds keel over when they swallow a cane toad. With no predators to control the population, cane toads have proliferated and spread over much of the western coast of Australia. I would recommend watching the documentary on cane toads-an unnatural history for a humorous and informative account on cane toads.