Exotic Animals - Major Pests
Cane Toad
Family: Bufonidae (True Toads)
Order: Anura (aka Salientia)
Class: Amphibia
Scientific names: Rhinella marina
How to Identify a Cane Toad
Sound
The male Cane Toad has a distinctive call which has been described by some as sounding like a motor running, a high-pitched broken brrrrrr sound, similar to a telephone dial tone or a long loud purring trill.
Eggs
Cane Toad eggs are quite distinctive from native frog eggs as they are laid in very long chains with individual eggs looking like small black beads encased in a tube of jelly. Each egg, which is predominantly black but also sometimes has sections of white, is held within a clear individual jelly capsule which is then connected to the long strand of jelly. Often, the eggs are placed in double rows along the strand. More than one female Cane Toad will usually lay in the same pool of water and each female lays up to 35,000 eggs. This means the strands often become tangled together, making them look like a large mass of eggs. Using a stick or a rake, if you try to pick the mass of eggs up you will see the long, individual strands hang down. Some native frogs also lay strands of eggs, however these strands often have sections where the eggs are clumped and do not form a straight strand of eggs like the Cane Toad's. Because native frogs do not lay nearly as many eggs in one sitting as the Cane Toad, their eggs are not as easy to find.
Tadpoles
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The tadpoles of Cane Toads are a shiny, uniform jet black colour on top and they have a plain dark bluish grey to black belly which is not transparent. Their tail is rounded at the tip, is short, thin, and uniformly jet black and only about 1.25 to 1.5 times the length of the body. The fins are totally transparent. Toad tadpoles are small and only grow to a maximum 30mm in total length, with the body about 11mm in length at most. The body is an oval shape, pointed at the snout and is often very broad across the gills. The eyes are positioned in from the sides of the head and they have nostrils which are distinct. Toad tadpoles tend to form large, slow-moving groups. They do not come up to the surface to ‘breathe’ like the tadpoles of native frogs do. Some native species will also form schools, however these species are larger and usually dull brown or pale in colour.
Juveniles
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With a smoother, darker skin, darker blotches and bars and a lack of obvious parotoid glands on their backs, juvenile Cane Toads are quite different in appearance to adult toads. Any toads that are under 4cm in length can particularly look like some native frogs. The dominating feature which helps to distinguish them from native frogs is their upright stance. They also tend to cluster together near water and are active in the daytime. If you are unsure what you are looking at then it is best to take juveniles to a frog expert to identify. It is a good idea to wear rubber gloves when handling them.
Adults
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Adult Cane Toads are usually very large and are generally between 9-15cm in length (3.5 to 5 inches), although they have been known to grow up to 24cm (9.4 inches) in length! They are heavily built and the skin on top is rough, dry and covered in warts. The colour can vary from grey, olive, yellow brown to red brown, but they are never brightly coloured. Their underparts are lighter in colour and are usually a mottled brown. Their heads are bony with a pointed snout and over their eyes are distinctive ridges which meet above the nose. Behind and slightly below each eye is a distinctive circular ear drum. On top of each shoulder is a large sack – this is the toxin-producing parotoid gland. Cane Toads have slightly webbed, leathery hind feet while the front feet have no webbing and are relatively small in size. Cane Toads have a particularly upright stance and they walk or move small distances in short, rapid hops, unlike many native species which leap. Male toads are smaller and have more warts than females. When it is the breeding season males will develop ‘nuptial pads’, which look like dark lumps, on their first two fingers. These assist the male with holding onto the female while mating.
Adult Cane Toads are both nocturnal and visual hunters. They need a lot of food to survive so they often congregate in open areas, such as on roads or lawns, where they can spot their next meal. They prefer places that are well lit, such as below street lamps or around houses, because this is where insects are attracted in the evenings. They are poor climbers and are unable to jump very high. Unlike some of our native species they cannot climb up smooth surfaces. Cane Toads are a terrestrial animal, however they do need daily access to water. This means the toad is most vulnerable during the dry season as they need to stay close to water as the environment begins to dry up.
For further information, relating to reporting sightings of cane toads, capturing toads, taking part in toad musters or for information on trapping:
Phone: FrogWatch on 1800 243 564
Email: toadreport@frogwatch.org.au
Go to: www.frogwatch.org.au
