- Also called:
- bufo toad, giant toad, or marine toad
- Related Topics:
- bufotoxin
- On the Web:
- NSW Government - Department of Primary Industries - Cane toad (Oct. 25, 2026)
cane toad
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What is a cane toad?
The cane toad, Rhinella marina, is a large, terrestrial, omnivorous amphibian native to South and Central America. They have reddish to grayish brown coloring, and they typically range from 10 to 17 cm in length, but the largest on record weighed about 2.7 kg.
They are considered one of the most invasive pests on Earth because they reproduce rapidly, are highly toxic, and eat almost anything. They were introduced to other parts of the world, like Australia, to control crop-eating insects, but they failed to control the beetle population and became a threat to native species.
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Where do cane toads come from originally?
Cane toads are native to South and Central America, ranging from the Amazon basin to the lower Rio Grande valley of Texas. They are terrestrial creatures that can thrive in urban areas and undisturbed natural environments such as dunes, coastal grasslands, and mangrove swamps.
In the early 20th century, countries introduced cane toads to control crop-eating insects. They are now considered one of the most invasive species. The Australian government introduced 2,400 cane toads in 1935 to sugarcane farms in Queensland to control beetles. The toads failed to control the beetle population, reproduced rapidly, and now number in the millions, covering most of northeastern Australia.
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How can you recognize a cane toad?
Cane toads (Rhinella marina) are identifiable by their reddish to grayish-brown coloring, sometimes with red, yellow, or dark green tinges. They are typically 10 to 17 cm (4 to 7 inches) long, but can grow much heavier than their usual 1.5 kg (3.3 pounds), with the largest recorded at 2.7 kg (about 6 pounds).
Key characteristics include prominent cranial crests above the eyes and large parotid glands on their shoulders that extend down the sides of their bodies. Their call sounds like a slow, low-pitched sound, similar to a faraway tractor. Cane toads have dry, rough, and bumpy skin.
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Why were cane toads introduced to places like Australia?
Cane toads were introduced to various regions, including Australia, in the early 20th century to control crop-eating insects. In 1935, the Australian government brought in 2,400 cane toads to Queensland sugarcane farms to combat beetles that were damaging the plants' roots. While the toads failed to control the beetle population, they thrived, and the cane toad population in Australia now numbers in the millions.
These toads are now considered one of the most invasive species because of their rapid breeding, short development time, high toxicity, voracious appetite, and overall hardiness, which allows them to thrive in a variety of environments. Their introduction has disturbed multiple ecosystems, as they can outcompete native species for food and habitat.
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What problems have cane toads caused in new environments?
Cane toads, native to South and Central America, have become a highly invasive species in many regions after their introduction as a form of pest control. Their rapid breeding, varied diet, and toxicity have led to significant ecological problems.
Cane toads outcompete native species for food and habitat, causing declines in prey populations and other amphibians. The toxins they secrete can kill predators that mistake them for local amphibians, further disrupting ecosystems. Their introduction has harmed regions, including Australia, the Philippines, Papua New Guinea, Guam, Hawaii, Florida, and several Caribbean islands. Because of the issues they have caused, deliberate introduction of cane toads to new lands is now rare.
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How do cane toads defend themselves from predators?
Cane toads have several defense mechanisms against predators. Throughout their lives, cane toads are poisonous to some extent. When threatened, they turn sideways to aim a parotid gland at their attacker and secrete a milky-white toxin called bufotoxin. This toxin contains cardioactive steroids that impact the heart and central nervous system. Many predators have learned to avoid cane toads because of this. The toxin can be fatal if a cane toad is licked, bitten, or consumed by a pet or native species.
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cane toad, (Rhinella marina), a large terrestrial omnivorous amphibian considered to be one of the most invasive pests on Earth. This toxic species is native to South and Central America but is now found across the world, from Australia and Oceania to Caribbean islands and parts of the United States, after being introduced as a natural pesticide on sugarcane plantations.
Physical characteristics
Cane toads have reddish to grayish brown coloring on the back, with occasional tinges of red, yellow, or dark green. Somewhat flat in appearance, the toads typically range from 10 to 17 cm (4 to 7 inches) in length. Though they usually weigh about 1.5 kg (3.3 pounds), they can grow much heavier. The largest on record weighed up to 2.7 kg (about 6 pounds). Males are smaller and wartier than females.
Notable characteristics of the cane toad include prominent cranial crests above the eyes and large parotid glands on the shoulders that extend down the sides of the body. Cane toads communicate with a slow low-pitched call that is said to sound similar to a faraway tractor.
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Diet
Cane toads are omnivores that consume a wide variety of foods. Their activity increases at night, when they forage and hunt for prey, using mainly their eyes to detect potential plant and animal food sources. Although known for their ability to eat small insects, cane toads also eat vegetation as well as small mammals, birds, reptiles, and other amphibians. Cane toads will even eat human garbage, table scraps, and food left out for pets. In addition, they can filter out organic material from water.
Reproduction
Cane toads reach sexual maturity at 18–24 months of age, after which they reproduce rapidly and can mate multiple times a year. Reproduction may occur in any season, but the species prefers the start of the wet season. Female cane toads lay gelatinous strings of eggs in fresh and even brackish bodies of water, including ponds, slow-moving creeks, and canals. Anywhere from 5,000 to more than 30,000 eggs are released at a time and are fertilized externally by males.
After two or three days, tadpoles emerge from the eggs, and they develop into toads in a stage lasting from 3 to 20 weeks, depending on food availability and water temperature. Cane toads can reach full maturity within a year in tropical regions. The species’ typical lifespan in the wild is about five years. A group of cane toads is called a knot or nest.
Toxicity
Cane toads are poisonous to some extent throughout their lives. Both their eggs and their tadpoles are poisonous, and adults produce a milky white toxin called bufotoxin from the parotid glands. When threatened, cane toads turn sideways to direct a parotid gland toward their attacker and secrete the toxin. Bufotoxin contains cardioactive steroids that affect the heart and central nervous system.
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In humans, bufotoxin may be absorbed through the eyes, nose, or mouth, and the toxin may irritate the skin and eyes when contacted. Many predators have learned to avoid cane toads, and the toxin may be fatal if a cane toad is licked, bitten, or consumed by a pet or a native species.
Natural habitat and invasive species
Cane toads are native to South and Central America, inhabiting a range from the Amazon basin to the lower Rio Grande valley of Texas. They are ground-dwelling creatures that can live in urban areas as well as in undisturbed nature. Cane toads absorb water through their skin and require some form of moisture in their environment to survive, which allows them to live in habitats such as dunes, coastal grasslands, and the edges of mangrove swamps and rainforests.
Large populations of cane toads can be found around the world. In the early 20th century several countries introduced the species to control crop-eating insects. The species’ expansion has been well documented, and cane toads are now considered to be one of the most invasive species.
In 1935 the Australian government introduced 2,400 cane toads to sugarcane farms in Queensland to control beetles that destroyed the plants’ roots and stunted their growth. The cane toads failed to control the beetle population, and they reproduced rapidly and flourished. The country’s cane toad population now numbers in the millions and covers most of northeastern Australia. The toads are advancing westward by 40–60 km (25–40 miles) per year. In response, the Australian government is taking active measures to humanely reduce their numbers.
Other regions harmed by the introduction of cane toads include the Philippines, Papua New Guinea, Guam, and Hawaii. Florida and several Caribbean islands also had cane toads introduced to their habitats. In Florida they are considered an invasive species, and humane killing of cane toads is permitted.
The cane toad’s rapid breeding, short development time, high toxicity, voracious appetite, and overall hardiness allow them to thrive in a variety of environments. Their introduction has disturbed multiple ecosystems, as they can outcompete native species for food and habitat. Though their deliberate introduction to new lands is now rare, cane toads can still be introduced accidentally through the transport of wood or of potted plants containing the species.