Frequently Asked Questions
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Whilst many questions on cane toads are addressed here, it is worthwhile visiting CaneToadsinOz.com for great, up to date scientific information
presented in easy to understand terms by Dr Richard Shine, a
specialist in cane toads. There, he and his team debunk many of
the common cane toad myths around.
The area covered by south-east Queensland roughly incorporates the area from just north of Yeppoon and south to the Gold Coast and aligns a little west of Biloela and east along the coast.
Frogs, like any other native creatures (at least) are valuable and offer things to the environment that are unique to the frog world. Without them, you'd be surprised at just how much of an ecosystem would collapse, like removing the capstone from an archway. Hence, they can be referred to as a 'capstone species'.
It is also widely believed that frogs are sensitive indicators of the general health of the environment because of their permeable skins that are affected by water, soil and air quality (Collins and Storfer, 2003; Elzinga et al. 2001). Thus, if any of these factors are found to be in poor condition, then there is a good chance frogs will not be present, or at the very least unhealthy. It is also not exaggerating to say that there are likely to be other organisms in the vicinity that are also undergoing some form of health-related stress.
Contrary to how it seems with humans, in the frog world the males are the ones that do all the 'talking', or more accurately, calling. Males call to attract a female to mate and to warn off other males. Each frog species has it's own distinct call.
Chyrtid (Batrachochytrium dendrobatidis) is a fungus that is capable of killing entire amphibian populations whilst causing sporadic deaths on others, via the infectious Chytridiomycosis disease. It was discovered in 1993 amongst dead and dying Queensland frogs, and has since been identified in all Australian States, including the Australian Capital Territory, but not the Northern Territory. The disease also exists in Africa, the Americas, Europe, New Zealand and Asia but is thought to have arrived in Australia from one of these countries. Despite the numerous locations where Chytrid fungus exists, it is relatively confined to cool, wet climates.
The disease has proven very effective in reducing frog populations, causing mass mortality in some species whilst others have appeared less susceptible. In Australia, at least four species appear to have become extinct, of which the disease was implicated as the primary factor. These include two local South East QLD species, the Southern Gastric-brooding Frog (Rheobatrachus silus) and the Southern Day Frog (Taudactylus diurnus). Both species occurred along the Blackall-Conondale Ranges prior to their apparent extinction between 1979 and 1981. Nearly a dozen more species have experienced dramatic declines and now have lower abundances and smaller distributions.
Amphibians have very unique skin which allows for the passage and regulation of water and electrolytes between the frog and its outside environment. Unfortunately, this means frog skin is very susceptible to invasion by the fungus and is thought to result in the disrupted function of the skin, causing the frog to die.
Symptoms of the disease include abnormal amphibian activity, such as sitting out during day light hours and reduced mobility. Red colouration may be present on the stomach and limbs, whilst half-closed eyes and a depressed or bent over stance may also be present. Sloughs of skin is also often visible and can accumulate of the outside of the animal.
Chytridiomycosis is a contagious disease, however it only infects amphibians. The Chytrid fungi spores infect frogs when their skin comes into contact with water containing these spores, from other infected animals. Therefore proper hygiene and handling protocols are important when coming into contact with amphibians. Current permit information can be found on the QLD Frog Society's Laws and Permits for keeping Frogs page. Creating a frog-friendly garden is however always encouraged. Visit Frogs in Your Garden by the QLD Frog Society and/or Attracting frogs to your garden by the Queensland Government - Department of Environment and Heritage Protection (DEHP).
Chytrid fungus is widespread throughout most of Australia, and as such is difficult to contol. There are no proven methods to date that enable for the control of the disease in the wild, despite various research projects and scientific attempts. Understanding the impact of chytridiomycosis in wild populaions will allow for imrpoved mitigation and contol of the threat. This means monitoring frog populations for the disease and detecting new outbreaks is very important, as is creating restricted and controlled areas to protect certain susceptible species.
If you are travelling through potentially infected areas, appropirate hygiene controls are necessary, including washing of hands, footwear and equipment before and after leaving such areas, and only handling amphibians when absolutely necessary, using single-use vinyl gloves or a clear plastic bag. If necessary, only purchasing amphibians from licensed suppliers is another way to prevent the spread of the disease.
If you come across a sick frog or mass mortality in the wild, please contact your local community group, frog society or environmental department immediately. Additonally, animals suspected of chytrid disease can be collected using gloves and send for diagnosis.
For more information on Chytridiomycosis, check out this fact sheet from the Australian Government.
It is now illegal to transport frogs, their eggs and tadpoles from location to location, due to potential spread of the chytrid fungus and unsuitability of new habitat location/type. Scientists and community groups do not encourage the keeping of frogs as pets. Permits are necessary and not all frog species are suitable. Current permit information can be found on the QLD Frog Society's Laws and Permits for keeping Frogs page. Creating a frog-friendly garden is however always encouraged. Visit Frogs in Your Garden by the QLD Frog Society and/or Attracting frogs to your garden by the Queensland Government - Department of Environment and Heritage Protection (DEHP).
There is only one species of toad in Australia, the cane toad (Rhinella marina, also known as Chaunus marinus or Bufo marinus). The various Latin scientific names arise from ongoing research into their molecular relationships, with the latest researches proposing the Rhinella Genus name as the most accurate.
The cane toad was imported on purpose to Australia back in 1935 as a biological control in an attempt to quash the cane beetle that had been decimating the Queensland sugar cane industry. This was unsuccessful (Urban et al. 2007), however no-one can be sure of this as there was no base-line data prior to the cane toads' arrival to compare the before and after result of cane beetle populations.
Rhinella marina is native to Texas and Brazil and is America's most common and widespread amphibian (Zug and Zug, 1979).
Whoa! Hold up, only one question at a time!
Since its release, the cane toad has spread over 1.2 million kilometres between northern New South Wales, throughout Queensland, across the top of Northern Territory and recently into northern Western Australia (Australian Government, 2009). Hence the term 'invasive species'. Whilst the cane toad has caused some local species population declines, these species generally recover soon after, having understood to avoid eating toads or have become resistant to their toxins. Species unfamiliar with cane toads who may eat them can die though due to their unfamiliarity to their toxins (Zug and Zug, 1979) within the Australian landscape.
Below is a list of some native wildlife that a few studies have found to be negatively impacted by the cane toad. It is argued however that this evidence is only anecdotal (unreliable or subjective) and that there are quite likely to be other causes of declines. These populations usually recover though, as was the case of a study on crocodiles in tropical Australia, which found no population decrease despite the presence of cane toads (Somaweera and Shine, 2012).
In April 2005, the cane toad was listed under the Environment Protection and Biodiversity Act 1999 (EPBC Act) as a key threatening impact on the survival and abundance of native species and their respective communities.
- Northern quoll (Australian Government, 2009)
- Ornamental snake (Australian Government, 2009)
- Green and golden bell frogs (Australian Government, 2009)
- Rainbow bee-eaters (Boland, 2004)
- Crocodiles (Letnic et al., 2008)
- Bluetongue lizards (Price-Rees et al. 2010)
- Frog tadpoles (Crossland et al. 2008)
Cannibalistic behaviour increases in arurans (frogs and toads) when density of individuals is high or when their food source languishes (Crump, 1992). Scientific research reveals that cane toads do not eat frogs, instead preferring other forms of food, but on occasions will eat whatever fits in their mouth. Some native frogs will eat other native frogs on occasion too. Cane toads, juveniles and cane toad tadpoles do not eat frog tadpoles (Crossland et al. 2011).
Researches have implemented conditioned taste aversion (CTA) baits, as experimented on the northern quoll in a means to prevent quolls from consuming cane toads and dying afterwards. Identifying toad breeding habitat and modifying these to make them less suitable for breeding is another means of deterring these animals from spreading.
The use of the cane toad tadpole bait, developed by Prof. Rob Capon is one of the more recent and effective means of controlling cane toads at the tadpole stage. See the next question and answer for more information.
To discover if toad tadpoles actively search for cane toad eggs, funnel traps containing toad and native frog tadpoles were placed in a water body, positioned to mimic natural egg deposition. Some traps also had toad eggs placed inside. Control traps contained no toad eggs. The results found that the addition of toad eggs to traps returned a huge (86-fold) increase in the rate of toad tadpoles captured. A few native frog tadpoles were collected in both trap treatments, but much less than toad tadpoles caught, suggesting this might be an effective way of removing toad tadpoles without affecting many frog tadpoles.
Scientists found that the toad tadpoles were attracted to conspecifics (of the same species) by the chemicals that make up the toads' toxicity. This resulted in cane toad tadpoles eating cane toad eggs to decrease competition amongst the species for food, resources etc. It is also thought these tadpoles gain a nutritional benefit from eating the eggs, and other dead toad tadpoles. Thus, the scientists were able to take advantage of the cane toads' own toxins, which ironically is their downfall. A significant sized body of water was able to be completely eradicated of cane toad tadpoles by removing them as they were attracted to conspecific eggs. Whilst Professor Rick Shine does not expect this method to totally eradicate cane toads from Australia, but it is certainly possible in local areas. This method is also quite effective because it targets the reproduction of cane toads, by eliminating their eggs and tadpoles in concentrated areas, rather than roaming adults.
(Crossland and Shine, 2011; Crossland et al., 2011).
These baits are now available to QLD Frog Society members. Contact the QLD Frog Society to sign up and request these baits for local cane toad tadpole control.
The list below describes what to look out for in cane toad tadpoles.
This information was taken from the document 'Native tadpole...or cane toad?', available from Frogs Australia Network (resource no longer available). Please also refer to the 'Be Toadally Sure' campaign for images of Cane Toad tadpoles.
- Body is a uniform black colour
- Tail muscle is a uniform black colour and has clear fins
- The tail is only about 11/4 to 11/2 times the length of the body, with a rounded tip
- Tadpole is small, max body length of ~28mm, body only ~11mm
- Body is ovular and broader than it is deep, especially across the gills
- Eyes are positioned in from the side of the head with distinct nostrils
- The belly is black or a very dark bluish-grey
- Cane toad tadpoles often swim together in large swarms
- Cane toad eggs are laid in distinct strands of clear jelly and black eggs
- so if you're quite certain they are cane toad eggs these can be picked/scooped up and left to dry out of water
A 2015 paper by Prof. Rick Shine and his team argue that the fridge/freezer method is the best way to humanely dispose of cane toads. Whilst this method has up to recently received a lot of unsubstantiated criticism, Rick demonstrates through empirical evidence that the cane toad body cools at the same rate as the cane toad brain. This means that whilst freezing the animal it is unable to perceive pain (Shine et al. 2015). Cane toads should first be placed in the fridge for several hours until they are unconscious, before then placing them in the freezer for several days.
Aside from this method which is ONLY to be used if you are 'toadally sure' you have a cane toad, other control methods include:
There are other methods which ARE NOT appropriate to use for cane toad control. These include:
- Vegetating the edges of any water bodies/ponds in your yard acts as a natural barrier to cane toads as they prefer open, easy-access entry to breed in the water. This is not to say you will not totally prevent toads from clambering over low-growing plants to reach water, but it should deter most toads from doing what they do best!
- Targeting cane toads at the egg and tadpole stage, which has been discussed above is the most effective control method as many individuals can be targeted at once.
Finally, it must be stressed that before you decide to do anything with a cane toad, be absolutely certain it is a cane toad as there are many local native frogs with a similar appearance to toads in the eye of the untrained.
- An aerosol product called 'Hopstop' which is created to paralyse the toad once it has been sprayed, eventually killing it. Time until death takes approx. 45 mins and therefore this product is not endorsed here. For more on this product, have a read of this article from the Queensland Frog Society Inc.
- Kicking, clubbing or hitting cane toads just for the 'fun' of it. Cane toads feel pain like any other animal and do not deserve a cruel death for what is not their own fault.
- Spraying toads with Dettol is also not encouraged as the chemical burns which is simply inhumane.
The skin glands on all frogs produce many compounds that cover and help to protect the skin from bacteria and microbes that may infect the skin, and from predation. These compounds could therefore be generally toxic to some animals and humans. The best advice is do not put a frog in your mouth, and wash your hands after touching them (if you need to touch in the first place).
Please go to the 'Be Toadally Sure' page to learn all of the differences between frogs and cane toads.
For the more scientifically minded, visit the Shine Lab website of the University of
Sydney where you can find the latest scientific research on
cane toads, by Dr Richard Shine and 'Team Bufo'.
(2012) 'Shine Lab - Shine Lab - University of Sydney'. The University of Sydney, accessed 26 June, 2012, http://sydney.edu.au/science/biology/shine/canetoad_research/.
Australian Government (2013) 'Chytridiomycosis (Amphibian chytrid fungus disease) - Fact sheet'. Australian Government: Department of the Environment, http://www.environment.gov.au/resource/chytridiomycosis-amphibian-chytrid-fungus-disease, accessed 15 June, 2014.
Australian Government (2009) 'Australian Government Policy on Cane Toads'. Australian Government: Department of the Environment, Water, Heritage and the Arts, available at http://www.environment.gov.au/biodiversity/invasive/publications/cane-toad/pubs/cane-toad-policy.pdf, accessed on 22 May, 2012.
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, pp. 53-62.
Collins, J. P. and Storfer, A. (2003) 'Global amphibian declines: sorting the hypotheses'. Diversity and Distributions, 9, 89-98.
Crossland, M. R., Brown, G. P., Anstis, M., Shilton, C. M. and Shine, R. (2008) 'Mass mortality of native anuran tadpoles in tropical Australia due to the invasive cane toad (Bufo marinus)'. Biological Conservation, 141, pp. 2387-2394.
Crossland, M. R., Hearnden, M. N., Pizzatto, L., Alford, R. A. and Shine, R. (2011) 'Why be a cannibal? The benefits to cane toad, Rhinella marina [Bufo marinus], tadpoles of consuming conspecific eggs'. Animal Behaviour, 82, pp. 775-782.
Crossland, M. R. and Shine, R. (2011) 'Cues for cannibalism: cane toad tadpoles use chemical signals to locate and consume conspecific eggs'. Oikos, 120 327-332.
Crump, M. L. (1992) 'Cannibalism in amphibians' - In: Elgar, M. A. and Crespi, B. J. (eds), 'Cannibalism: ecology and evolution among diverse taxa', Oxford University Press, pp. 256-276.
Elzinga, C. L., Salzer, D. W., Willoughby, J. W. and Gibbs, J. P. (2001) 'Monitoring Plant and Animal populations'. Blackwell Science, USA, pp. 360.
Letnic, M., Webb, J. K. and Shine, R. (2008) 'Invasive cane toads (Bufo marinus) cause mass mortality of freshwater crocodiles (Crocodylus johnstoni) in tropical Australia'. Biological Conservation, 141, 1773-1782.
Shine. R, Amiel. J, Munn. A.J, Stewart. M, Vyssotski. A.L, and Lesku. J.A (2015) Is "cooling then freezing" a humane way to kill amphibians and reptiles? Biology Open (2015) 00, 1-4 doi:10.1242/bio.012179
Price-Rees, S. J., Brown, G. P. and Shine, R. (2010) 'Predation on toxic cane toads (Bufo marinus) may imperil bluetongue lizards (Tiliqua scincoides intermedia, Scincidae) in tropical Australia'. Wildlife Research, 37, pp. 166-173.
Somaweera, R. and Shine, R. (2012) 'The (non) impact of invasive cane toads on freshwater crocodiles at Lake Argyle in tropical Australia'. Animal Conservation, 15, pp. 152-163.
Zug, G. R. and Zug, P. B. (1979) 'The Marine Toad, Bufo marinus: A Natural History Resumé of Native Populations'. Smithsonian Contributions to Zoology, 284, pp. 1-68.