Cane toad

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This article provides information about the identification, biology, impact and management of the cane toad.

Introduction

The cane toad (Rhinella marina) or giant toad is native to south and central America. It has been introduced to many countries, including northern and eastern Australia. The cane toad is a declared pest under the Biosecurity and Agriculture Management Act 2007 (BAM Act) in Western Australia (WA).

The Western Australian Organism List (WAOL) contains information on the area(s) in which this pest is declared and the control and keeping categories to which it has been assigned in WA. Use the links on this page to reach cane toad in WAOL.

Identification and behaviour

Cane toads are the only true toads present in Australia. They are heavily-built and are typically 100–150mm in length. They can grow to more than 230mm and over 1kg in weight, but in areas with high toad densities individuals rarely exceed 100mm in length. The skin of cane toads is dry and rough rather than moist and slippery like many native frogs.

The backs of male toads have large warty lumps that feel like sandpaper when rubbed, while females have slightly smoother skin with less prominent lumps. The body colour on top ranges from dull brown to yellowish or blackish (never bright greens, yellows or reds) and there is rarely any marked pattern. The light underparts are usually mottled with brown.

The large glands behind the head can sometimes exude a poisonous milky substance when the toads are disturbed. Other distinctive features include a visible eardrum, bony ridges on the head, slight webbing between the toes (but not the fingers) and lack of enlarged pads (suckers) on the digits.

The call of the male is a guttural trill, sustained for about 30 seconds, and very different from most native frog calls.

Cane toads are most active at night, often in open areas such as roads and lawns. They sometimes congregate beneath streetlights and other lights to catch insects. On land, toads walk and hop short distances, but do not leap or climb smooth surfaces like some native frogs. They also typically sit more upright than many native frogs. Where toads have established in the wild they can occur in much larger numbers than native frogs.

The egg masses (spawn) of cane toads are unlike those of most native frogs and the tadpoles are also different. Toads produce chains of black eggs about 1mm in diameter enclosed in a thick transparent gelatinous cover, forming long strands about 3mm thick.

Toad tadpoles are jet black and reach a maximum of about 30mm from head to tail. They have non-transparent abdominal skin, their bodies are wider than they are long and their tails are relatively short with a dark central muscle and clear fins. The tadpoles of native frogs are generally very dark (but not jet black) with lighter or transparent abdominal skin and longer tails. Toad tadpoles form large slow-moving groups at the water’s edge and do not rise often to the surface to ‘breathe’. In contrast, tadpoles of native frogs regularly rise to the surface, having developed lungs sooner.

Newly-formed toads (metamorphs) are small (9-11mm) compared to adults and are conspicuous by their large numbers and daytime activity near their watery breeding sites. They develop into juveniles that have a distinct camouflage pattern that diminishes with age.

Distinguishing features of a cane toad.
Distinguishing features of a cane toad. Photo: Department of Parks and Wildlife.

Further information

For further information, or to report a cane toad sighting, please contact the Cane Toad Hotline 1800 44 WILD (1800 449 453), or the Department of Parks and Wildlife.

Food

Cane toads mostly eat insects, but will consume whatever else they can fit into their mouth including spiders, snails, small frogs, other cane toads, reptiles and mammals. Unlike native frogs, toads also eat inanimate items including pet food, cigarette butts and animal excreta.

Distribution and habitat

The natural range of the cane toad includes Brazil, through central America to eastern Mexico and Texas. Feral populations now occur in many countries including other parts of the Americas and many island groups. Toads were introduced into Puerto Rico, Hawaii and the Philippines in the 1920s and 1930s, and to Queensland in 1935 to control insect pests of sugar cane, but there is no evidence that this was effective.

Since their introduction to Australia, toads have proved to be highly invasive and computer modelling indicates that they could spread over most coastal areas of the continent. They are still spreading in eastern and northern Australia, including two off-shore islands in the Northern Territory. They are also spreading west and now occur in the Kimberley district of WA.

Reproduction and longevity

In Australia, cane toads normally breed from June to January although breeding may occur throughout the year. Females produce 8 000-35 000 eggs at a time and can breed at least twice a year. Local conditions greatly influence the number of eggs and tadpoles that survive to become adults. Toads normally lay eggs in slow-moving freshwater streams or dams, but can also use brackish water and temporary pools and puddles. Tadpoles hatch in 48-72 hours and, depending on temperature and food, they can develop into metamorphs in 17-180 days, reaching sexual maturity in approximately 18 months. Toads can live for at least 15 years in captivity and individuals have bred for at least five years in the wild.

Impact

Native animals affected by cane toads in Australia include frogs, reptiles such as large goannas, crocodiles and blue tongue lizards, fish and mammals such as quolls (native cats). They are vulnerable to cane toad toxin (all toad life stages are poisonous) and are often killed when cane toads first arrive in an area, leading to population reductions. Toads also compete with native species for food, consuming large numbers of native invertebrates, and they carry diseases that can spread to native frogs. Although there are some reports of native predators consuming cane toads safely, the longer-term impact of cane toads on native fauna is not yet clear and is the subject of ongoing research.

Toads eat beneficial insects like dung beetles and constitute an economic threat to beekeepers. Cane toad poison is highly toxic to most animals and causes pain if it comes in contact with eyes. Without emergency veterinary care, dogs and cats which mouth or bite cane toads sometimes die.

Map showing the current distribution of the cane toad in north eastern Australia and predicted distribution in north western and souther Australia.
Current and predicted distribution of the cane toad in Australia.

Management

Biological control may be the only long-term means of reducing the number of cane toads across large areas. Research to date has been unable to find a suitable disease or parasite specific to cane toads that will provide effective control.

Various physical methods for reducing toad numbers including traps, hand removal and fences are being used by government and volunteer groups in an attempt to slow the westward movement of toads. The effectiveness of these techniques is still being investigated.

Anything being moved from toad-infested areas outside or within WA could contain cane toads and this has already occurred. Vigilance is required by freight companies and travellers as toads have been found in pipes, containers and fruit packaging as well as pot plants, shoes and camping gear. Until effective control methods are available, quarantine checks, public awareness and the removal of detected toads will reduce their rate of spread.

Key to distinguish cane toads from native frogs.
Key to distinguish cane toads from native frogs.

Native frogs sometimes mistaken for cane toads

Western Australia has 78 species of native frogs. The photographs below, arranged by geographical region, will assist in identifying native frogs that are sometimes mistaken for cane toads. Many of these native frogs burrow and only emerge after rain. This sometimes gives the impression that they have suddenly ‘arrived’ in the area. Frogs can also vary greatly in colour and patterning, so these photographs should be used as a guide only.

South-west

Motorbike frog
Native frogs mistaken for cane toads - Motorbike frog or western tree frog (Litoria moorei) (53–74mm). Variable in colour and markings. Usually has a pale dorsal stripe and dark stripe from nose though eye and ear. Suckers on fingers and toes. Photo: D RobinsonDistribution: Murchison to Cape Riche.
Moaning frog
Native frogs mistaken for cane toads - Moaning frog (Heleioporus eyrei) (45–63mm). Often has prominent eyes. Brown with greyish, white or yellowish marbling on back and sides. Photo: D RobinsonDistribution: Coastal south-west and south coast, Geraldton to Cape Arid.
Banjo frog
Native frogs mistaken for cane toads - Banjo frog (Limnodynastes dorsalis) (60–75mm). Usually has reddish colour to inner thigh, a pale dorsal stripe and a prominent lump on calf. Photo: R Browne-CooperDistribution: Lower Murchison to Cape Arid.
Hooting frog
Native frogs mistaken for cane toads - Hooting frog (Heleioporus barycragus) (60–86mm). Chocolate-brown frog with raised yellow spots on sides. Photo: G HaroldDistribution: Darling Scarp, Bullsbrook to Darkan and Dryandra.
Native humming frog
Native frogs mistaken for cane toads - Humming frog (Neobatrachus pelobatoides) (37–44mm). Dull green to pale yellow with irregular dark brown/grey-green patches. Usually has a fine pale red stripe down the back. Photo: R JohnstoneDistribution: Central west to south coast and agricultural areas between.

Gascoyne

Water-holding frog
Native frogs mistaken for cane toads - Water-holding frog (Cyclorana platycephala) (40–68mm). Flattened head with eyes pointing up. Toes (but not fingers) are fully webbed. Photo: B MaryanDistribution: Gascoyne district east through the desert.

Kimberley and Pilbara

Giant frog
Native frogs mistaken for cane toads - Giant frog (Cyclorana australis) (71–102mm). Variable in colour and patterning. Has a poorly defined dark stripe from the nose through the eye to the jaw, and folds of skin on the sides of the body. Photo: C MillsDistribution: East Pilbara to the Kimberley and Gulf of Carpentaria.
Native ornate frog
Native frogs mistaken for cane toads - Ornate frog (Opisthodon ornatus) (36–42mm). Large bulging eyes, can be elaborately patterned, occasionally with lighter dorsal stripe or band, limbs barred with dark bands. Photo: G HaroldDistribution: Kimberley
Northern burrowing frog
Native frogs mistaken for cane toads --Northern burrowing frog (Neobatrachus aquilonius) (48–59mm). Yellow with dark irregular blotches, short limbs, ear drum not visible. Photo: B MaryanDistribution: West Kimberley, Pilbara, east Gibson Desert.
Desert spadefoot
Native frogs mistaken for cane toads - Desert spadefoot (Notaden nichollsi) (42–65mm). Dull orange/olive grey/brown, short legs, long fingers and toes. Black ‘warts’ and scattered spots. Exudes smelly poison when disturbed. Photo: B MaryanDistribution: Southern Kimberley, Pilbara and through the Great Sandy Desert to the Northern Territory.