Cane toads are native to South and Central America. They are extremely hardy animals and voracious predators of insects and other small prey.
These qualities led to their introduction into Australia as a means of controlling pest beetles in the sugar cane industry in 1935, before the use of agricultural chemicals became widespread.
Since then, the range of cane toads has expanded through Australia’s northern landscape and they are now moving westward at an estimated 40 to 60 km per year.
Cane toads reached Brisbane by 1945, Burketown in north-western Queensland by the early 1980s, Iron Range on the Cape York Peninsula by 1983 and the tip of the Cape by 1994. Cane toads are capable of poisoning predators that try to eat them and they continue to spread across Australia.
There is no broad scale way to control this pest but scientists are developing a better understanding of the impacts they have on the environment and the ways in which assets, such as rare and vulnerable wildlife, can be protected.
Cane toads forage at night in a wide variety of habitats. The toad is a ground-dwelling predator, primarily eating terrestrial and aquatic insects and snails. Toads will even take food left out for pets. The toads can be accidentally transported to new locations, for example in pot plants or loads of timber.
Cane toads need constant access to moisture to survive. Instead of drinking, they absorb water through the skin on their belly — from dew, moist sand or any other moist material.
If forced to stay in flooded conditions, cane toads can absorb too much water and die. They can also die from water loss during dry conditions. In Australia there are no specific predators or diseases that control cane toads.
The toads can breed at any time of year but seem to prefer the weather conditions that occur with the onset of the wet season. They will lay their eggs in still or slow-moving waters. Females can lay 8000–30 000 eggs at a time.
The cane toad defends itself through poison and is poisonous, to varying degrees, during all its life stages. Adult cane toads produce toxin from glands over their upper surface, but especially from bulging glands on their shoulders — these exude venom when the toad is provoked.
While some birds and native predators have learned to avoid the poison glands of adult toads, other predators are more vulnerable and die rapidly after ingesting toads. Toads contain poisons that act on the heart and on the central nervous system. The poison is absorbed through body tissues such as those of the eyes, mouth and nose.
Adult cane toads may compete with native animals, particularly for shelter. For example, a 2004 study showed that cane toads ruined one-third of nest attempts of ground-nesting rainbow bee-eaters by usurping their nest burrows and preying upon their eggs and young nestling.
There is unlikely to ever be a broad scale method available to control cane toads across Australia.
Researchers are beginning to understand the toad’s impact on native fauna and to appreciate the ways in which native species are adapting to the presence of cane toads and recovering from the impact of their arrival. Protecting our most vulnerable native species on a local scale is the focus of current planning around cane toads.
The Government will continue to work with regional natural resource management organizations and with state governments to achieve outcomes for our environment and sustainable agriculture.
Crickey Conservation Society Foundation 2020.