Cane toad

Origin

The natural range of cane toads (Rhinella marina) extends from the southern United States to tropical South America.

Description

Cane toads (Rhinella marina) are large heavily-built amphibians with dry warty skin. They have a bony head and over their eyes are bony ridges that meet above the nose. They sit upright and move in short rapid hops. Their hind feet have leathery webbing between the toes and their front feet are unwebbed. Adult cane toads have large swellings - the parotoid glands - on each shoulder behind the eardrum

Cane toads may be grey, yellowish, olive-brown or reddish-brown, and their bellies are pale with dark mottling. Average-sized adults are 10-15 cm long. The largest female measured in Queensland was 24 cm long and weighed 1.3 kg. Male cane toads are smaller and wartier than females. During the breeding season males develop dark lumps (nuptial pads) on their first two fingers; these help them cling to a female while mating. Their mating call is a long loud purring trill.

Young cane toads have a smooth dark skin with darker blotches and bars, and lack conspicuous parotoid glands.

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. Cane toad spawn is unique in Australia. It is 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.

Source: Office of Environment and Heritage

Think you’ve found a cane toad?

Find out how to tell the difference between a cane toad and a native frog.

These native frogs are often mistaken for cane toads in NSW:

  • Eastern pobblebonk frog
  • Giant burrowing frog
  • Northern banjo frog
  • Peron’s tree frog
  • Tusked frog
  • Great barred frog
  • Ornate burrowing frog
  • Common eastern froglet
  • Spotted marsh frog.

Learn about these native frogs on the Australian Museum’s Frog ID website, or download their app.

If you spot an animal you think may be a cane toad, carefully contain it (but don’t harm it) and take photos. Then report the sighting to us using our online reporting form (including your photos), or if it’s in a national park, report the sighting to the Office of Environment and Heritage.

Impact

The cane toad is tough and adaptable as well as being poisonous throughout its life cycle. It has few predators in Australia, which is bad news for competing native amphibians, and it may be responsible for the population decline of the few snakes and other species that do prey on it.

Cane toads were deliberately introduced from Hawaii to Australia in 1935 to control scarab beetles that were pests of sugar cane. 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. In February 2009, cane toads crossed the Western Australian border with the Northern Territory (over 2000 km from the site they were released 74 years before). To the south, cane toads were introduced to Byron Bay in 1965 and then spread to Yamba and Port Macquarie on the north coast of NSW in 2003.

Cane toads are considered a pest in Australia because they:

  • poison pets and injure humans with their toxins
  • poison many native animals whose diet includes frogs, tadpoles and frogs' eggs
  • eat large numbers of honey bees, creating a management problem for bee-keepers
  • prey on native fauna
  • compete for food with vertebrate insectivores such as small skinks
  • may carry diseases that are can be transmitted to native frogs and fishes.

Cane toads can be accidentally transported to new locations, for example in pot plants or loads of timber.

Behaviour

Cane toads eat almost anything they can swallow, including pet food, carrion and household scraps, but most of their food is living insects. Beetles, honey bees, ants, winged termites, crickets and bugs are eaten in abundance. Marine snails, smaller toads and native frogs, small snakes, and small mammals are occasionally eaten by cane toads. The tadpoles of cane toads eat algae and other aquatic plants which they rasp off with five rows of tiny peg-like teeth. They also filter organic matter from the water. Large tadpoles sometimes eat cane toad eggs.

Adult cane toads are active at night during the warm months of the year. During the day and in cold or dry weather they shelter in moist crevices and hollows, sometimes excavating depressions beneath logs, rocks and debris. They can survive the loss of up to 50% of their body water, and can survive temperatures ranging from 5ºC - 40ºC.

Cane toads are prolific breeders, requiring only a small pool of water of almost any nature.

Cane toads can breed in most still or slow-flowing water, and tolerate salinity levels up to 15%. Male cane toads start calling for mates after the first summer storms (in Australia that is about September) or when water temperatures reach 25º C. The choruses peak in January and finish by March. The males congregate after dark around shallow water and mount females as they arrive at the water's edge. The male grips the female in the armpits (this is called axillary amplexus) and she releases her eggs, which are fertilised externally by the male's sperm.

Females lay 8,000 to 35,000 eggs at a time and may produce two clutches a year although only a small proportion of young survive to adulthood. The eggs hatch within 24-72 hours and the tadpole stage may last from 3-20 weeks, depending on food supply and water temperature - generally a range of 25-30ºC is needed for healthy development. The tadpoles gradually change (metamorphose) into toadlets 1-1.5 cm in length that leave the water and congregate in large numbers.

Legislation

In Australia, the importation of live animals is controlled by the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Under the EPBC Act, restrictions have been established as a safeguard to protect Australia against exotic pests and diseases that are considered a threat to the Australian environment, economy and the wider community and to protect endangered species from uncontrolled trade which can lead to population decline and extinction of endangered species.

In order to be eligible for import into Australia, animal species must be listed on the Commonwealth Government’s Live Import List under the EPBC Act. The cane toad is only eligible for import for research purposes in high security facilities.

In NSW, everyone has a biosecurity duty (under the NSW Biosecurity Act 2015 ) to prevent the spread of cane toads beyond the area where they are currently established in north-east NSW (to the Clarence River).

Information on the management of cane toads in national parks can be found on the Office of Environment and Heritage cane toad page.

Information sources

Australian Museum

Office of Environment and Heritage

Department of the Environment and Energy