Cane toads (Rhinella marina) are an invasive species. Accurate identification is crucial to manage their spread and protect native wildlife. This guide details how to distinguish cane toads from other amphibians.
Key Physical Characteristics
Cane toads are typically large amphibians, with adults commonly measuring 10 to 15 cm in length, though some females can reach up to 24 cm. Their skin appears dry, rough, and covered in warts, varying in color from grey, yellowish, olive, or brown to reddish-brown. The underside is usually cream-colored, sometimes with darker blotches.
One of the most distinguishing features is the presence of large, triangular or kidney-shaped parotoid glands located behind each eye, extending onto the shoulders. These glands secrete a milky, potent toxin known as bufotoxin when the toad feels threatened. Cane toads also possess prominent bony ridges above their eyes that meet at the snout. Their pupils are horizontal, often with golden irises.
Their legs are relatively short and stout. Cane toads have minimal or absent webbing between their front toes, but they do exhibit some leathery webbing between their hind toes. Unlike some native frogs, they lack discs or adhesion pads on their toes, which means they cannot climb smooth vertical surfaces.
Distinguishing From Native Species
Native frogs generally have smoother, more moist, and often slippery skin, contrasting with the cane toad’s dry, warty texture. Many native species also lack the large, prominent parotoid glands behind the eyes. This distinction is important, as many native species can be mistaken for cane toads.
The bony ridges above the eyes of a cane toad, which meet at the snout, are a unique feature not found in most native amphibians. For instance, the southern toad (Anaxyrus terrestris) has smaller, oval parotoid glands and well-defined cranial crests that resemble horns, unlike the cane toad’s large, triangular glands and different head structure.
Cane toads have horizontal pupils, whereas some native frogs may have round or vertical pupils. Native frogs often have webbed front feet or toe pads, allowing them to climb, which cane toads generally cannot do. Always consider a combination of these characteristics for reliable identification.
Behavioral and Habitat Indicators
Cane toads are predominantly active at night, foraging for food after dusk during warmer months. During the day or in extreme weather, they typically seek shelter under rocks, logs, or in depressions. Their movement is characterized by short, rapid hops or a slow, lumbering walk, rather than the leaping motion common to many native frogs.
They often thrive in disturbed environments, including urban areas, gardens, golf courses, and agricultural lands, frequently congregating around artificial light sources that attract insects. Cane toads require access to moisture, absorbing water through their skin from dew, moist sand, or other damp materials. They breed in still or slow-moving water bodies, including temporary puddles, and females lay long strings of black eggs. A female can lay between 8,000 and 35,000 eggs in a single clutch, potentially producing two clutches per year. Their call is a low-pitched trill, sometimes described as sounding like a distant tractor or a telephone dial tone.
What To Do If You Spot One
If a cane toad is identified, avoid direct handling without proper protection due to their toxic secretions. The bufotoxin they produce can cause irritation, temporary blindness, or pain if it contacts mucous membranes like eyes, mouth, or nose. Dogs and other pets are particularly susceptible to poisoning if they mouth or lick a cane toad, which can be fatal.
It is advisable to report sightings to local environmental authorities, pest control services, or wildlife agencies. Many regions have reporting systems, such as online platforms, to track their spread. If containment is necessary and permitted by local guidelines, use a bucket or container to safely capture the toad without direct contact.
In some areas, humane management methods are recommended by authorities for population control. The stepped hypothermia method, involving refrigeration followed by freezing, is considered a humane approach for euthanasia by some guidelines, but this should only be undertaken if authorized and instructed by local authorities. Always confirm the species before taking any action, as native amphibians are protected.