|[Note Guidelines] Photographer's Note|
|I know that images of this particular toad have been posted before but I thought I'd be able to add some information about the toad to this previous post and felt I'd got a fairly good shot of this specimen in our garden one night.|
The cane toad, Bufo marinus, is an invasive pest species in many countries (e.g. Australia and the USA - Florida) having been introduced to these areas from its native south-central America. The cane toad has become a well known and severe pest in Australia where about 100 individuals were introduced in 1935 to Gordonsvale in northern Queensland. The toad was originally introduced as a biocontrol agent to control sugar cane beetles but were completely ineffective at at controlling the beetle and in the process became a pest themselves. Since then the toad has spread to the west into the Northern Territory, reaching the well known Kakadu National Park in 2001, and south into New South Wales. It rate of expansion to the south is estimated at about 1.3 km a year and renewed efforts are being made in an attempt to prevent the toad from spreading into Western Australia through the Kimberley area.
The cane toad is a voracious predator and will eat other amphibians, reptiles, small mammals and insects (anything it can fit in its mouth basically). But aside from it direct impact through its hefty appetite it also contributes to the loss of many native Australian fauna as a result of the bufotoxins that are secreted through the large parotid glands (and the smaller glands on the rest of the back) to the rear of the tympanum. These glands secrete a milky substance when the toads are provoked and can also cause skin irritations in humans.
The success of the cane toad, as with many pest species, is its ability to maximise its opportunities. Without and natural predators to control their numbers the toad is able to maximise survival of tadpoles and continue its spread into new areas. Cane toad females can lay on average 8000 to 30000 eggs at a time throughout the year when conditions are favourable whereas local frog species lay only about 1000-2000 eggs each year.
The toad does require constant access to water so the spread of the toad into some parts of Australia will be limited by the lack of this resource. The toads also seem to prefer the warmer temperatures and cooler regions may also restrict the ingress of toads.
There are a number of trapping methods that have been suggested to control the numbers but it does not look like the toad will be eradicated from Australia in the near future. Perhaps evolution will beat us to the line by enabling native species to evolve a resilience to the toad bufotoxin allowing these species to recover.
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- [2007-01-30 11:45]
Good macro of this pest, but as always humans tried to play God. Sharp and very detailed with focus on the eye and face. Well done.
- [2007-01-30 13:19]
bravo guy splendid
I do like this capture of the most unfortunate introductive irradiction schemes we have ever seen within Australia. As of right know they have pennetrated into Kakado and are having a large affect on the carnivorous marsupials of Northern Territory.
Here in Qld as I am sure you Know we have had predatory adaptations from turtles eating the tadpoles, birds turning the toad over and eating the stomache as well as my favourite the Keelback snakes being totally amuned to the bufotoxin.