Introduction
The Cane Toad was introduced from the tropical island of Hawaii in the year 1935 by one of Australia’s bureau, The Sugar Bureau Experiment Station. Cane toads were introduced as a measure to curb the problem of the native cane beetle otherwise known as Domolopedia albohirtum. The toads were first bred in captivity and they bred rapidly to a population of 102 toads by the month of August in 1935.
The toads were first released in the Northern Queensland, as was referred then, in a few areas specifically the areas around Carns. After sometime the cane toads were released tp other areas in the second drive.
At first the toads were released temporarily owing to the emerging concerns over the environment. Once the concerns were addressed the toad release was resumed in the month of September 1936.
The cane toad multiplied rapidly in a short span of time compared to other species in the same habitat. The toads had breed rapidly leading to the toads migration to other areas beyond the areas around the Queensland.
This can be attributed to the toad’s large and wide body, longer legs compared to other amphibians that helps in the toads movement from place to place and part of the frog, ten per cent, was affected by arthritis ( Tyler, 1944, 112).
The cane toad is a large amphibian, slightly heavily built with dry as well as warty skin cover ( Kessler, 2011, 7).
Reasons for Introduction
Cane toads were introduced in Australia in the year 1935 from South America ( Kessler, 2011, 3). The major reason for introduction of the cane toad was to control the French Cane Beetle and the Grey Back Cane Beetle that were destroying acres and acres of sugar cane crops( Kessler, 2011, 4).
The natural habitat for the cane toad is in the Central and South America ( Tyler, 1994, 123). They are basically terristerial animals but from time to time require the acquatic environment for rehydration as well as for breeding purposes ( Kessler, 2011, 11). In Australia the cane toad is found in mangrove areas, in rainforests as well as around sand dunes.
The toad breeds in slow-flowing or stagnant but clean water bodies. These kind of climate is favourable for the rapid growth of the cane toad. The Australian climate encourages the toads rapid and unparalleled growth. The female cane toad lays approximately 7,000 to 35,000 eggs at a go and breeds at least twice in a year.
The laid eggs hatch after seventy two hours into tadpoles. In a period of about twenty one days to a half a year the tadpoles develop to toadlets. A cane toad has an average lifespan of five years (Tyler, 1994, 156).
Another factor that led to the successful establishment of this pest is the fact that the cane toad has no known natural predator such as the fresh water crocodile or crawling reptiles. The tiger snakes have been known to eat the cane toads but they later die from the toads poisonous venom that it produces once it feels threatened or in danger. This venom is excreted from glands that are located right above each shoulder of the cane toad.
Another factor that has lead to the cane toad successful establishment is the fact that cane toad has a venom secreting gland on either side of it body right above the shoulders. The gland excretes venom immediately the toad feels threatened or in danger.
Another factor is that the Cane Toad is poisonous in all its stages of its life cycle. A cane toad excretes poisonous venom in all its developmental stages therefore insuring its survival no matter what stage of development the toad is. The toad has no stage where it is any less vulnerable to danger as it uses its poisonous venom as a protection measure to ensure its survival. Pros and cons of the method used to control pests.
Threat to other natural species
The cane toad eats a variety, a wide variey, of different species. A cane toad can eat approximately two hundred times as much as other amphibians therefore a large variety of prey. The cane toad consumes almost anything it can find that can fit in its mouth. It therefore consumes too much of what is in its environment making it a potential threat to other species living in the same habitat as the toad.
The cane toad breeds very fast and opportunistically as well. They breed rapidly especially in habitats that are generally warm all year round. As the cane toad continues to consume other species in the habitat essentially colonising this habitats preventing the other natural species from breeding.
Predation
Cane toads breed rapidly in a given area over a relatively short interval compared to other species. Since this toads consume large amounts of food therefore leaving it in completion with other species over food. They indirectly alienate other species from accessing this food. Cane toads feed on almost anything from ants to termites, flies and everything a cane toad can manage to put in its mouth.
In addition to this, the cane toads are in completion with other native species for things like food, water resources as well as shelter. The cane toad has been regarded as a major factor leading to the decline of the native species population because of the cane toad’s rapid breeding, consumption of large volumes of food as well as the toad being a predator.
Lethal Toxic Venom
In all the development stages in a cane toads life cycle its is poisonous in all the stages right from the tadpole stage all through to the adult stage, from the egg stage to adulthood. The cane toad has venom poison excreting glands on either of its shoulders that it utilises whenever it feels threatened or in danger (Barker et al 1995, 3).
If the venom is ingested it leads to convulsions, a rapid increase in heartbeat rate, over production of saliva and in later stages causes paralysis. It is therefore dangerous to other inhabitants especially the native species.
References
Barker, J; Grigg, G.C; Tyler,M.J. (1995) A Field Guide to Australia Frogs. Surrey Beatty & Sons.
Kessler, R. (2011) Long Dead Cane Toads Continue to Haunt Australian Wildlife. ScienceMagazine. Web.
Lawsons, W.J. (1987) The Cane Toad, Bufo Marinus: A Bibliography (AES Working Paper). School Of Australian Environmental Studies.
Patterson, E.K. (1936) The World’s First Insect Memorial.’’ The Review of the River Plate’’. nd.
Shaw, D. M. (2011) Prickly Pear and the Morning After. Healthnewsdigest.com. Web.
Tyler, M.J. (1994) Australian Frogs A Natural History. Reed Books.