Managing Cane Toads (Bufo marinus) in Australian gardens
This introduced species is very common, very conspicuous and known to most Queenslanders. Cane Toads are also known, appropriately, as Giant Toads. Cane Toads are native to North, Central and South America. Females can weigh 2.5kg and have a length of 26cm!
Cane Toad eggs and tadpoles are very distinct. The eggs are small, black and usually numerous, in ‘strings of jelly’, deposited on the bottom of ponds. They may be laid in virtually any water – fresh or brackish; still or running; clear or muddy; deep or shallow; and natural or man-made, including swimming pools..Tadpoles, too, are black, small and numerous. They have shorter tails than native frogs and swim about in a group.
This is a very poisonous species. A cocktail of highly-toxic, biologically-active substances has been identified from Cane Toads. These substances are concentrated in the ‘warty’ skin and in two large glands, one on each side of a toad’s head. Toxins are also present in a toad’s muscles, bones and body organs, and in eggs and tadpoles. However, Cane Toads pose little threat to ‘life and limb’ unless they are eaten or their skin secretions have contact with a person’s eyes or mouth. Cane Toads are very passive animals and should always be avoided. Their toxins make Cane Toads a potential threat to some domestic animals like dogs and to some wildlife.
It is well-documented that many species of native vertebrates die if they eat Cane Toads, their eggs or tadpoles. Only a handful of species (the Snapping Turtle, Elseya latisternum; the Freshwater Snake, Tropidonophis mairii; the crocodiles, Crocodylus porosus and C. johnstoni; and the Water Rat, Hydromys chrysogaster) can sometimes prey safely on them. However, the full extent of the impact of the Cane Toad on native wildlife is not, and may never be fully understood. This is because it is not easy to separate their impact from other destructive impacts due to increasing human population and associated conservation problems such as clearance and degradation of native vegetation, pollution of waterways, the spread of introduced plant and animal pests.
Although it was introduced as a biological control for cane beetles, which are pests in sugar cane, it was unsuccessful at this task. Cane Toads rapidly spread from their places of introduction, and are still advancing south and west. The Cane Toad is now a pest.
Removal and humane disposal of Cane Toads from your local area may help reduce numbers.