The cane toad is covered with bumpy olive to reddish brown skin on the back. This resembles leather in its feel and is mostly dry. On their underside this is white or a pale yellow and is speckled with brown spots.
Their large head has bony ridges over the eyes.Their legs are short and on the front the toes are not webbed while on the back foot they have basal webbing.
Behind the head are bumps on either side, these are the parotid glands which deliver poison to predators.
Cane toads are the world’s largest toads. Males are smaller than females. On average they measure 10-15cm (3.9-5.9in) long and weigh up to 1.5kg (3.3lbs). One exceptionally large female was found which measured 24cm (9.5in).
The cane toad is a carnivore when it is an adult. They will feed upon almost anything that can fit in their mouth. The majority of their diet is insects but they will also eat toads and frogs, small mammals and snakes. As they move in to human areas they will feed on carrion, pet food and household scraps.
When in their tadpole stage the cane toad feeds on algae and aquatic plants.
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The native range of the cane toad is across South and Central America. Their range starts in the far South of Texas, USA and runs down through Mexico, Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Ecuador, Venezuela, Guyana, Trinidad and Tobago, Suriname, French Guiana, Brazil, Bolivia and Peru.
They are highly invasive and have been introduced to a number of islands in the Caribbean and throughout the Pacific Ocean including Papua New Guinea and the Philippines. They were also introduced to Hawaii.
Their most high profile introduction was to Australia in 1935 in an attempt to control pests which ate sugar cane. Since their release in Queensland they have spread South to New South Wales and West through the Northern Territory and in to Western Australia.
Cane toads are highly adaptable and due to this can survive in almost any habitat. They are found in sand dunes, coastal heath, rainforest, mangroves, grassland, woodland and urban areas.
They are reliant on water for their survival and as such their habitat needs to be near a source of moisture such as a river or moist sand.
While the cane toad is capable of breeding during any part of the year but there is typically a peak after periods of rain.
Males will make their call by the water’s edge in the dark and wait for females to approach the water where they can mate with them. The eggs are released by the female on to plants or debris in the water and fertilized externally by the male.
They are capable of increasing their population rapidly as a single female can lay up to 20,000 eggs in a single clutch. It takes just 2-3 days for these eggs to hatch. Infant mortality is high with as little as 0.5% of hatchlings surviving to adulthood in some areas.
Tadpoles may be preyed upon by insects, turtles and snakes. Some of these animals have shown a tolerance to small amounts of toad poison.
Toads begin their life as a tadpole which lives solely in the water and resembles a small fish with a long tail. These tadpoles are entirely black. If conditions are ideal for their development the tadpoles will metamorphose in to adult toads within a month.
Sexual maturity is achieved by one year old in most of their natural range though in colder regions this can be delayed to 2 years.
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The call of the cane toad sounds similar to a running motor.
They are primarily nocturnal. During the day they will hide under moist crevices or hollows or dig a hole under a log or rock.
Cane toads are incredibly adaptable which has led to their successful spread across the Earth. One such adaptation is the ability to lose 50% of their body water.
Predators and Threats
To defend against predation the cane toad is equipped with poison which they can deliver through glands on the back of the neck as well as their skin. It can also be sprayed from the parotid gland at attackers. This poison is capable of causing death within 15 minutes for animals which attempt to eat them.
In humans the poison can cause temporary blindness and intense pain.
Cane toads typically prove more of a threat to other animals in area they those animals do to them. In some parts of Australia which they have spread to cane toads are seen as responsible for wiping out much of the native predators in these areas.
The cane toad is also known as the ‘marine’ or ‘giant’ toad.
They are the world’s largest toad species.
Since their introduction to Australia in the 1930s cane toad numbers have increased from 3000 to 200 million.
At present no highly effective control method has been found for cane toads that would allow for their removal from areas which they have been introduced to that would not affect native frog species.
Sam Fraser-Smith from Brisbane, Australia – Bufo marinus (Linnaeus, 1758) – cane toad, giant toad, marine toad Uploaded by Amada44, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=25213986
By Froggydarb, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1552230
Sam Fraser-Smith from Brisbane, Australia / CC BY (https://creativecommons.org/licenses/by/2.0)
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