Cane toad (Rhinella marina)

Description and biology

Cane toads are among the largest toads and are recognizable by their robust, squat bodies, dry warty skin and large parotoid glands behind each eye. These glands secrete a complex mix of chemicals commonly referred to as bufotoxins; the secretion can be irritating or lethal to many predators and is a key reason for the species' impact when introduced outside its native range. Adults are opportunistic feeders with an omnivorous diet that includes insects, other invertebrates and occasionally small vertebrates; tadpoles develop in still or slow-moving water.

• Body form: stout, short limbs adapted more for walking and short hops than long leaps.
• Reproduction: breeds in ponds, ditches and similar waters where females lay long strings or masses of eggs that hatch into aquatic tadpoles.
• Life history: adaptable to varied habitats, from agricultural areas to urban environments; can tolerate disturbed landscapes.

Native range and introductions

The species is native to parts of Central and South America; for regional context see resources on Central American and South American amphibians. Cane toads have been transported by people to other regions as a form of biological control and for other reasons. Those human-mediated movements are documented in accounts of introductions, and established non-native populations now occur in parts of Oceania and throughout parts of the Caribbean and Pacific islands.

Ecological impacts

Where introduced, cane toads have caused substantial ecological disruption. Their toxins can kill or injure native predators that attempt to eat them; they can outcompete native amphibians and other small animals for food and habitat; and dense populations can alter local food webs. The severity of impacts varies by location and depends on the vulnerability of native fauna. In their native range, cane toads are an integral part of ecosystems and subject to natural checks such as native predators and parasites.

Management, research and human interactions

Management strategies used where cane toads are invasive include public education, targeted removal, exclusion fencing, trapping and research into longer-term control methods. Biological control proposals require careful assessment because of risks of unintended consequences. Scientists have also studied cane toad toxins for pharmacological properties and used the species in ecological and evolutionary research. Public guidance in affected regions emphasizes keeping pets and livestock away from toads and reporting sightings to local authorities.

Further reading and resources

For summaries and conservation guidance consult regional amphibian guides and invasive-species resources; see general species accounts here, regional overviews for Central America and South America, and information on introductions and management on introduction history and in affected regions such as Oceania and the Caribbean.