The cane toad is a large toad native to Central and South America. These toads have been introduced to several other countries in a futile attempt to control other pests. The most well-known of these attempts was in Australia, where the cane toad was introduced in 1935 from Hawaii to control the cane beetle. The cane beetle is a major pest of sugar cane, and it was hoped that the cane toad would control these pests. Instead the toads became pests themselves.
Worst of all, the cane toad was ineffective at eliminating the cane beetle. Instead of eating the beetles, they began eating everything else in sight, including bird’s eggs and native frogs.
The cane toad isn’t particularly adapted to Australia’s climate. Many die of dehydration during the dry season. But this is a resilient species that can survive losing half their body water. They can also survive a temperature range from 5 to 40 degrees Celsius. Another sign of their resilience is the fact that they will eat anything and everything. Cane toads kept in captivity have grown to ten inches in length and weigh up to nine pounds. Wild toads can live up to five years. Cane toads reproduce rapidly, because females lay between 8,000 and 35,000 eggs at a time.
Certain developmental factors give the cane toads advantages over other species. They are hearty animals and voracious predators of insects and other small prey. Tadpoles of cane toads grow faster than most native frogs, so they are easily able to compete for food. The biggest advantage they have is their toxicity. They have an array of highly toxic chemical defenses available at almost all stages of their lives. Many natural predators die when exposed to cane toads.
Cane toads are considered a serious problem in Australia. They kill most native animals that normally eat frogs. They are only harmful to humans if the poison is swallowed.
Tourists traveling along Australia's east coast by car hire are bound to run into a cane toad race at least once during their travels. A bucket of cane toads is collected and each is fitted with a number on its back. They are let loose from the bucket in the middle of a dance floor and whichever toad is the first to leave the dance floor is the winner. Cane toad races are an example of how Australians try to find humor in the degree to which these pests have overstayed their welcome.
Resources
Learn more about the cane toad from the following resources:
Controlling cane toads has been difficult, because things that kill them also kill frogs. It has recently been discovered that they are susceptible to being killed and eaten by meat ants. Lungworm parasites have also been found to be lethal to very small toads. Research is continually being done to try to find a way to bring these pests under control.
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