Cane Toad: Effects of the Invasive Species
Cane toads have gotten more than their fifteen minutes of fame. Documentaries and films alike have shown the plight of the cane toad and the people that have to learn to live with them as humorous. Yet, the toads keep dying and people that have had pets or children poisoned are not laughing. The toads were introduced to pacific islands, including Australia, the Caribbean, Fiji, and the Philippines during the first part of the 20th century. Sugar cane crops were being reduced by white grubs and beetles. The Australian Bureau of Sugar Experimental Stations imported the toads from Hawaii and released 3,000 into the plantations of North Queensland. The cane toad has proven itself to be resilient and prolific reproducers. There now exist millions of toads. They have played havoc with the natural order of native animals; prey and predators alike. One of the main reasons for the toads resiliency is its toxic body and ability to poison anything or anyone when it feels threatened.
Cane toads are native to central and South America. The Embera people of Colombia still use their poison dart guns for hunting. In their natural ecosystem the balance of cane toads is maintained between the links in the food chain. There are only about 20 adult toads per 100 meters in Central and South America. This is approximately 50-100 times lower than the introduced population in Australia.
Strategies to Contain and Eliminate Cane Toads
The toads are considered a pest in Australia as well as Florida where the Fish and Wildlife commission has asked residents to euthanize the frogs. In Australia, entire community mobilization efforts have taken place to rid themselves of the cane toad. The Caring for Our Country Initiative has put millions of dollars aside for the campaign against toads. The government states that putting up fencing around ponds can help keep the toads out of backyards and sensitive wildlife habitats. There have been calls to legalize attacks on cane toads. Animal rights groups insist that freezing the toads is the most humane way of killing the toads. Scientific research has come up with gene therapy whereby the sex of hatched toads will all be male. Another approach is to release small, juvenile cane toads into an area before the thousands of adult cane toads arrive. Scientists argue that wildlife many predators of cane toads learn from eating the toads if they can survive. With small toads released as teaching toads the animals would not ingest as much poison, learn from their mistake, and be able to survive the settlement of approaching cane toads. Strategies to end the toad invasion have led to some containment of the toads, but none as yet have been able to stop the spread of the frogs.
The effects to the wildlife of Australia have been less than expected. Many animals, including snakes and birds have learned to live with the toads. Birds have learned to flip over the toad and eat the less toxic tissues of the frogs belly. Snakes have developed immunities. Many animal populations that feed on the toads initially experience a die off, but their numbers return to mostly normal after learning to live with the toads. The goanna is an exception and some lizards as well have not been able to recover and are now listed as endangered. People have also been able to learn to live with the toads and been able to avoid most poisonings.
Fun Frog Fact
Cane toads can be transported by ship or truck. They can survive temperatures from 5-40 degrees Celsius. They also can conserve their water for long stretches of time. A plane unintentionally carried the frogs to Florida in 1955.
A: No, researchers have found that some toads roamed more than a kilometer at night.