If you have visited Australia you will have likely heard of the cane toad. This large toad is an invasive species and a major cause for concern there. Cane toads not only crowds out other wildlife by using up resources, they are also quite poisonous, killing off any potential predators.
History
The cane toad did not exist in Australia prior to 1935. However, the French's Cane Beetle and the Greyback Cane Beetle destroyed much of the sugar crop in the state of Queensland. Australian scientists imported cane toads from Hawaii to eat the beetles in 1935. Unfortunately, the toads not only ignored the beetles, but they began to multiply rapidly and eat other insects, other frogs and bird's eggs. On top of it, any species that tried to eat the cane toad would die from its poison.
Poison
The cane toad has a well-defined self-defense system as it is poisonous during every stage of its life. Most animals that eat adult cane toads will die from this poison. Even the tadpole is toxic to fish or other animals that eat it. Cane toads also excrete small amounts of poison, making animals sick that drink the water they have been in. The poison generally effects the heart and symptoms of cane toad poisoning include vomiting, shallow breathing and intense salivation. Death comes via cardiac arrest within 15 minutes.
Predators
Some predators have adapted to learn eat the cane toad without being poisoned. Since the poisonous glands are located on the back of the head, eating the frog's tongue or belly is safe for some animals. Keelback snakes and saw-shelled turtles feed on the tadpole and can handle low levels of cane toad toxins. Predators that have adapted to eat the adult cane toad include birds such as the heron, crow and kite, some species of rat and the estuarine crocodile.
Meat Ants
Australian scientists are trying to manipulate the meat ant to eat the cane toad as a way to control the population. Scientists have found that Australia's predatory meat ants can tolerate eating cane toads. In order to encourage the ants to eat the frogs, scientists are helping meat ants to establish colonies near toad breeding ponds. Since cane toads are slower than other frogs and toads, they are also more susceptible when the meat ants attack.
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