Guest post by Adrian Walker, “The Snake Whisperer”
The Amazon Toad (Bufo marinus) is a native species of Peru and widespread throughout lowland jungle in the región. During the 1920’s it was revealed that a primary source of the Toad’s diet came from the Grey Cane Beetle, a pest species in Australian sugar cane crops. Thus Australian scientists decided to determine whether it would be feasible to introduce the Toad as a control measure but scientific evaluations aren’t always done in 5 minutes and so an impatient group of Northern Australian cane farmers flew to South America and successfully smuggled a number of live toads into the country. This is believed to have happened in about 1927 and the Toads were first released near the village of Innisfail on the east coast and coincidentally a mere 45 kilometers from my home of many years.
Within a short space of time it became clear that the illegal introduction was a disaster as firstly the Toads found hundreds of preferred dietary items and so ignored the Cane Beetles but also were killing native Australian amphibians, birds and reptiles. The main method was of ingestion as Toads are easily caught and so lacking the knowledge that this prey species carried toxin glands, birds and snakes particularly died in their millions. Frogs also were subject to Toad predation and within a few years the Toads were classified as vermin.
Nearly 90 years from the initial introduction the Toad has spread westward to the border of Western Australia, some 2 and a half thousand kilometers and a similar distance to the south, occasionally reaching Sydney.
Thus a common Amazonian inhabitant became public enemy number one in another continent in a matter of a few years and studies have failed to determine a satisfactory means of eradication. Remarkable Toads in Australia have evolved longer legs than their cousins in South America, enabling them to cover greater distances as they continue their relentless march throughout the continent, causing widespread destruction in their wake.
A few Australian animals have learnt to detoxify the Toad before eating it, a simple technique of pecking out the toxin glands prior to consumption. For Snakes who have no such ability, the Toad remains a threat and one or two species have declined alarmingly and in some instances only survive on Toad free offshore islands. Marsupial carnivores such as the cat like Quoll have also declined and are now listed as endangered over the continent. A few still persist and it appears that Toad is no longer on the Quoll’s diet, another example of evolutionary trickery in that new habits can be conveyed genetically rather than taught.
This of course clearly illustrates that one man’s meat is another’s poison and stands as a clear reminder that biosecurity is a critical issue in all continents.
The Amazon Toad
Hi, this is Bill Grimes reporting from Iquitos Peru. Welcome back for more of the story. Adrian Walker and his family have moved out of our apartment. They are still considering their options to purchase or rent, or build a lodge. Adrian has been kind enough to write this series of articles for my Captain’s Blog and the Iquitos Times. We hope this is Chapter twelve of his new book, The Road to Iquitos. Click the links below to read chapters 1 – 11. Thank you.