Why were they introduced?
Cane toads were introduced to Queensland from Hawaii in 1935. They were brought over in an unsuccessful attempt to control the cane beetles that were killing the sugar cane crops. Cane Toads adapted well to the Australian environment and with no natural predators they quickly spread west to the Northern Territory and south into New South Wales.
Cane Toad (right) © Craig Cleeland
Why are they a problem?
Cane Toads are a serious conservation issue in Australia. As their populations increase, they threaten the existence of many natural ecosystems.
Cane Toads have a toxin that can kill most native animals that normally eat frogs. They therefore are a threat to Australian wildlife and pets. All stages of the Cane Toad's life-cycle are poisonous.Australian native fauna that have died from eating Cane Toads include goannas, snakes, dingoes and quolls.
Cane Toads have adapted well to the Australian environment because:
- they use a wide variety of habitats and thrive in urban and disturbed areas
- they eat a lot of different foods
- they breed quickly
These characteristics give Cane Toads a competitive advantage over our native frog species. In many habitats native frogs have been pushed out by the toads.
What do they look like?
Adult Cane Toads - are usually around 10-15 cm long. They have dry warty skin, bony ridges above their eyes, large swellings (parotoid glands) behind each shoulder and are grey, yellowish, olive-brown or reddish-brown in colour.
Photo (right) © Hal Cogger
Juvenile Cane Toads - can easily be confused with native frogs. They have smooth dark skin with darker blotches and bars, and lack conspicuous parotoid glands.
Photo (right) © Graeme Sawyer
Cane Toad tadpoles - are shiny black on top and have a plain dark belly and a short thin tail. They are smaller (less than 3.5 cm long) than most native tadpoles and often gather in huge numbers in shallow water.
Photo (right) © Graeme Sawyer
Cane Toad eggs - are laid in long strings of transparent jelly enclosing double rows of black eggs. The spawn tangles in dense dark masses around water plants, and hangs in ropy strands if picked up.
Photo (right) © Deborah Pergolotti
It is important to confirm the identity before disposing of a suspected toad, because two-thirds of suspects turn out to be harmless native frogs (such as the Banjo Frog) that need our protection.
For further information on Cane Toads visit:
Northern Territory Frogwatch - Cane Toad site
http://www.frogwatch.org.au/canetoads/
Australian Museum - Cane Toad FAQs
http://www.amonline.net.au/herpetology/faq/cane_toad.htm
Queensland Museum – Cane Toads
http://www.qmuseum.qld.gov.au/features/frogs/canetoad.asp
Australian Museum – Cane toad fact sheet
http://www.amonline.net.au/factsheets/canetoad.htm
Northern Territory Department of infrastructure, planning and environment - Cane toads in the top end
http://www.ipe.nt.gov.au/whatwedo/canetoads/
Frog Decline Reversal Project, Inc. - The Unwanted Amphibian http://www.fdrproject.org/pages/toads.htm