Cane toads in Australia

Invasive species


The cane toad in Australia is regarded as an exemplary case of a "feral species"thers being rabbits, foxes, cats, and Giant Mimosa. Australia's relative isolation prior to European colonisation and the industrial revolutionoth of which dramatically increased traffic and importation of novel speciesllowed development of a complex, interdepending system of ecology, but one which provided no natural predators for many of the species subsequently introduced. The recent, sudden inundation of foreign species has led to severe breakdowns in Australian ecology, after overwhelming proliferation of a number of introduced species for which the continent has no efficient natural predator or parasite, and which displace native speciesn some cases these species are physically destructive to habitat as well.


Introduction and spread
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A young cane toad.
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Cane toads were introduced to Australia from Hawaii in June 1935 in an attempt to control the native Cane Beetle (Dermolepida albohirtum). They bred immediately in captivity, and by August 1935 more than 102 young toads were released in areas around Cairns, Gordonvale and Innisfail in northern Queensland. More toads were released around Ingham, Ayr, Mackay and Bundaberg. Releases were temporarily limited because of environmental concerns but resumed in other areas after September 1936. Since their release, toads have rapidly multiplied in population and now number over 200 million and have been known to spread diseases affecting local biodiversity. The toads have steadily expanded their range through Queensland, reaching the border with New South Wales in 1978 and the Northern Territory in 1984. The toads on the western frontier of their advance have evolved larger legs; this is thought to be related to their ability to travel farther. As a consequence of their longer legs, larger bodies, and faster movement, about 10% of the leading edge cane toads have also developed arthritis. It is estimated that cane toads migrate at an average of 40 kilometres (25 mi) per year.


Ecological effects


The spread of cane toads in Australia from 1940 to 1980 in five year intervals.


The long-term effects of toads on the Australian environment are difficult to determine. Precipitous declines in populations of the Northern Quoll (Dasyurus hallucatus) have been observed after toads have invaded an area. There are a number of reports of declines in goanna and snake populations after the arrival of toads. The preliminary risk assessment of cane toads in Kakadu National Park stated that the predation of the cane toad by native wildlife is the greatest risk to biodiversity. Other factors, such as competition with native wildlife for resources, and the predation of the cane toad on native wildlife, were considered much lower risk factors but requiring further study. In the Northern Territory, goanna predation on cane toads has been linked to a rise in the amount of undamaged salt water crocodile eggs. Cane toads were present within a few days of the crocodiles hatching in April, 2007.


Numerous native species have been reported as successfully preying on toads. Some birds, such as the Black Kite (Milvus migrans), have learned to attack the toad's belly, avoiding the poison-producing glands on the back of the head. Reports in the Northern Territory suggest that a native frog, Dahl's Aquatic Frog (Litoria dahlii), is able to eat the tadpoles and live young of the toad without being affected by the poison that often kills other predators. This is believed to account for slower than expected infestations of toads in certain areas of the Northern Territory. Some snakes have been reported to have adapted smaller jaws so that they are unable to swallow large cane toads which have large quantities of poison. Another study, however, notes that the cane toad is adapting to a wider environmental range and may in the future be spreading into habitats currently not available. In 2009 it was found that the native meat ant is immune to the toad's poison and can successfully prey upon young cane toads. Whereas native frogs and toads have natural reflexes to avoid the meat ants, the cane toads do not tend to try to escape the ants, rather standing still when attacked.


As of 2005, ultraviolet light which attracts the moths the toads love has been used to lure and capture Cane Toads for extermination. In June 2006, the University of Queensland announced research into a gene to reverse the sex of female cane toads. This would lead to a population of males, and thus eliminate the population.


In popular culture


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A purse made from a cane toad.


The introduction and migration of the cane toad in Australia was popularised by the film Cane Toads: An Unnatural History (1988), which tells the tale with a humorous edge and is often shown in Environmental Science courses. Don Spencer, a popular children's entertainer, sang the song "Warts 'n' All", which was used in the documentary.


Attempts have been made to make use of dead cane toads, which can number in the thousands and cause hygiene problems. This includes processing the carcasses into liquid fertilisers. Their skin can be made into leather, and comical cane-toad purses, or coin-purses, retaining the toad fore-body, are sometimes seen (eg see accompanying photo).


Cane toads have also been known to be a significant source of food for humans in their native environment; cane toads are cooked by skinning them and taking out the internal organs (including the poisonous glands), and then roasting them. Many people who have eaten cane toads say they are like chicken except with a drier taste.[citation needed]


In Australian states where the cane toad is common, some rather cruel 'sports' have developed, such as cane toad golf and cane toad cricket, where cane toads are used as balls. In April 2005, Dave Tollner, a Northern Territory Member of Parliament, called for legalisation of attacks on cane toads. This was criticised by many animal and conservation groups who claim freezing is a more humane way to kill cane toads than hitting them with cricket bats. The short film Cane Toad - What happened to Baz? displays an Australian attitude towards the cane toad. This film won the "Best Comedy" award at the 2003 St Kilda Film Festival. The film relies on humour which Australians, especially, connect with, and screenings in overseas festivals have been less well received.[citation needed]


This was controversial in relation to an ad put out by the Tooheys beer company which showed people from New South Wales standing at the New South Wales-Queensland Border with golf clubs and lights, attracting Cane Toads just so they could hit them back across the border with the golf clubs.


The cane toad has been listed by the National Trust of Queensland as a state icon of Queensland, alongside the Great Barrier Reef, and past icons, the Royal Flying Doctor Service and the backyard mango tree (also an introduced species).


"Cane toad" is also a colloquial term for an inhabitant of Queensland, particularly the state's State of Origin rugby league team members and supporters.[citation needed]


Also, many websites when talking about Cane-Toads will also refer to the Queensland football team.


The invasive nature of cane toads was part of The Simpsons episode "Bart Vs. Australia".


See also


Invasive species in Australia


Conservation in Australia


References


^ "Institute for Molecular Bioscience, Killing off the cane toad". http://www.imb.uq.edu.au/index.html?page=48437. Retrieved 2006-12-06. 


^ "Toxic Toads Evolve Longer Legs, Study Says. 15/02/06. National Geographic News". http://news.nationalgeographic.com/news/2006/02/0215_060215_cane_toads.html. Retrieved 2006-05-19. 


^ Henry Fountain (October 16, 2007). "Arthritis Fails to Slow Invading Toads in Australian Fields". NY Times. http://www.nytimes.com/2007/10/16/science/16obtoad.html?_r=1&adxnnl=1&oref=slogin&pagewanted=all&adxnnlx=1193531451-eJSm5PA39SmnzeZ9ztvwsQ. Retrieved 2007-10-27. 


^ Tyler, M. J. (1994). Australian Frogs A Natural History. Reed Books. pp. 112. ISBN 0-7301-0468-0. 


^ Mayes, P.J.; Thompson, G. G. and Withers P.C. (2005). "Diet and foraging behaviour of the semi-aquatic Varanus mertensi (Reptilia: Varanidae)" (PDF). Wildlife Research 32: 6774. doi:10.1071/WR04040. http://publish.csiro.au/%3Fact%3Dview_file%26file_id%3DWR04040.pdf. 


^ "SSR164 - A preliminary risk assessment of cane toads in Kakadu National Park". http://www.deh.gov.au/ssd/publications/ssr/164.html. Retrieved 2006-05-22. 


^ Boland, C. R. J. (2004). "Introduced cane toads Bufo marinus are active nest predators and competitors of rainbow bee-eaters Merops ornatus: observational and experimental evidence". Biological Conservation 120 (1): 5362. 


^ "Cane toad impact will boost croc hatchling numbers, researchers say". http://www.abc.net.au/news/newsitems/200609/s1742950.htm. Retrieved 2006-10-15. 


^ "Cane Toads Present for Croc Hatching". http://sbs.discuvery.australia/canetoads.65145.d69f2544a66. 


^ Mitchell, D.; Jones, A. Hero, J.-M. (1995). "Predation on the Cane Toad (Bufo marinus) by the black kite (Milvus migrans)". Memoirs - Wueensland Museum 38: 512531. 


^ "NT frog 'eats' Cane Toad. 15/15/2004. ABC News Online". http://www.abc.net.au/news/newsitems/200412/s1265310.htm. Retrieved 2006-05-09. 


^ Phillips, Ben L.; and Shine, Richard (December 2004). "Adapting to an invasive species: Toxic Cane Toads induce morphological change in Australian snakes". PNAS 101(49): 1715017155. doi:10.1073/pnas.0406440101. PMID 15569943. http://www.pnas.org/cgi/content/abstract/101/49/17150. 


^ Urban, Mark C.; Ben L. Phillips, David K. Skelly, and Richard Shine (2007). "The cane toad's (Chaunus [Bufo] marinus) increasing ability to invade Australia is revealed by a dynamically updated range model". Proceedings of the Royal Society B: Biological Sciences. doi:10.1098/rspb.2007.0114. 


^ "Killer ants are weapons of mass toad destruction". London. http://www.timesonline.co.uk/tol/news/environment/article6007268.ece. Retrieved 2009-03-31. 


^ "Northern Australian Frog Database System". http://www.frogwatch.org.au/index.cfm?attributes.fuseaction=viewResearch&research_id=141. Retrieved 2006-05-20. 


^ "ABC news online: Gender bending could see cane toad's end". http://www.abc.net.au/news/newsitems/200606/s1656274.htm. Retrieved June 18, 2007. 


^ "Toads as Fertilizer - DirtDoctor.com - Howard Garrett". http://www.dirtdoctor.com/view_question.php?id=1470. Retrieved 2006-06-07. 


^ "Cane toad clubbing sparks controversy". http://www.abc.net.au/news/newsitems/200504/s1342444.htm. Retrieved 2006-06-20. 


^ "Vulgar, Violent Ads". http://www.walk.com.au/pedestriancouncil/Page.asp?PageID=866. Retrieved 2009-07-20. 


^ "Cane Toad Golf Out of Bounds". http://www.telegraph.co.uk/news/worldnews/1553992/Cane-toad-golf-out-of-bounds-says-RSPCA.html. Retrieved 2009-07-20. 


^ "National Trust Queensland National Icons". http://www.nationaltrustqld.org/qldicons.htm. Retrieved 2006-10-17. 


^ "How to kill a cane toad - Daily Telegraph". http://www.dailytelegraph.com.au/news/how-to-kill-a-cane-toad/story-e6frf0q0-1111113541375. Retrieved 2009-07-20. 


Further reading


Tyler, M. J. (1994). Australian Frogs A Natural History. Reed Books. ISBN 0-7301-0468-0. 


Barker, J.; Grigg, G.C.; Tyler, M.J. (1995). A Field Guide to Australian Frogs. Surrey Beatty & Sons. ISBN 0-949324-61-2. 


Lawson, Walter J. (1987). The Cane Toad, Bufo marinus: A Bibliography (AES working paper). School of Australian Environmental Studies, Griffith University. ISBN 0-86857-247-0. 


External links


Summary of cane toad research in Australia


Cane toad factsheet - Australian Museum


The Cane Toad - Australia's Amphibian Plague at h2g2


"Cane Toad - What Happened To Baz?", the prize-winning Australian animated short, hosted on a German site


Categories: Conservation in Australia | Fauna naturalised in AustraliaHidden categories: Pages containing cite templates with deprecated parameters | Articles needing cleanup from August 2009 | All pages needing cleanup | All articles with unsourced statements | Articles with unsourced statements from February 2009