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Cane Toad

2007 Schools Wikipedia Selection. Related subjects: Insects, Reptiles and
Fish

                                 iCane Toad

                             Conservation status

   Least Concern (LC)
                         Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Amphibia
   Order:   Anura
   Family:  Bufonidae
   Genus:   Bufo
   Species: B. marinus

                                Binomial name

   Bufo marinus
   Linnaeus, 1758
   Distribution of the Cane Toad. Native distribution in blue, introduced
   in red.
   Distribution of the Cane Toad. Native distribution in blue, introduced
   in red.

   The Cane Toad (Bufo marinus), also known as the Giant Neotropical Toad
   or Marine Toad, is a large, terrestrial true toad native to Central and
   South America. It is a member of the genus Bufo, which includes
   hundreds of different true toad species in different habitats
   throughout the world. The Cane Toad is a prolific breeder; females lay
   single-clump spawns with large numbers of eggs. Its reproductive
   success is partly due to opportunistic feeding: it has a diet, unusual
   among Anurans, of both dead and living matter. Adults average 10 to 15
   centimetres (4–6 in) in length; the largest recorded specimen weighed
   2.65 kilograms (5.84 lb) and measured 38 centimetres (15 in) from snout
   to vent.

   The Cane Toad has large poison glands, and adults and tadpoles are
   highly toxic to most animals if ingested. Because of its voracious
   appetite, the Cane Toad has been introduced to many regions of the
   Pacific and the Caribbean islands as a method of agricultural pest
   control, notably in the case of Australia in 1935, and derives its
   common name from its use against sugar cane pests. The Cane Toad itself
   is now considered a pest in many of its introduced regions, as its
   toxic skin kills many native predators when ingested.

Taxonomy

   The common name of "Cane Toad" is derived from the original purpose of
   using it to eradicate pests in sugar cane crops. The Cane Toad has many
   other common names, including "Giant Toad" and "Marine Toad"; the
   former refers to their size, and the latter to the binomial name, Bufo
   marinus. The specific epithet, marinus, was chosen by Carolus Linnaeus,
   and was based on an illustration by Albertus Seba. Seba mistakenly
   believed the Cane Toad to inhabit both terrestrial and marine
   environments. Other common names include "Giant Neotropical Toad,"
   "Dominican Toad," "Giant Marine Toad," and "South American Cane Toad."
   In Trinidadian English they are commonly called "Crapaud" (the French
   name for "toad").

   In Australia, the adults may be confused with species of the
   Limnodynastes, Neobatrachus, Mixophyes, and Notaden genera. These
   species can be readily distinguished from the Cane Toad by the lack of
   large parotoid glands behind their eyes. Cane toads have been confused
   with the Giant Burrowing Frog (Heleioporus australiacus), because both
   are large and warty in appearance; however, the Giant Burrowing Frog
   can be readily distinguished from the Cane Toad by its vertical pupils.
   Juvenile Cane Toads may be confused with species of the Uperoleia
   genus, because they all have large parotoid glands; juvenile Cane Toads
   can be distinguished from these species by the ridging around their
   eyes and the lack of bright colouring on their thighs .

   In the United States, the Cane Toad is morphologically similar to many
   species in the Bufo genus. In particular, it could be confused with the
   Southern toad (Bufo terrestris) and Fowler's toad (Bufo fowleri). The
   Southern Toad can be distinguished by the presence of two bulbs in
   front of the parotoid glands, and the Fowler's Toad has a pale,
   cream-white stripe that runs down the dorsal surface; the Cane Toad
   lacks this stripe.

   It is possible to confuse the Cane Toad with the Rococo Toad (Bufo
   schneideri), sometimes referred to as Schneider's Toad, whose range
   overlaps that of the Cane Toad. The Rococo Toad grows to nearly the
   same size, but has additional poison glands on its back legs which can
   be used to reliably identify it. Within its native range, the Cane Toad
   can be distinguished from the other true toads by the shape of its
   paratoid glands, and the arrangement of the ridges on its head.

Physical description

   Lightly coloured Cane Toad
   Enlarge
   Lightly coloured Cane Toad

   The Cane Toad is very large, reaching an average length of 10–15
   centimetres (4–6 in), and much longer in some cases. "Prinsen", a
   specimen kept as a pet in Sweden, is listed by the Guinness Book of
   Records as the largest recorded specimen, which weighed 2.65 kilograms
   (5.84 lb) and measured 38 centimetres (15 in) from snout to vent, or 54
   centimetres (21 in) when fully extended. A preserved specimen in the
   museum of Queensland was 24.1 centimetres (9.4 in) long 16.5
   centimetres (6.5 in) wide and weighed 1.36 kg (3 lb). They have a life
   expectancy of 10 to 15 years in the wild, and as long as 20 years in
   captivity.

   The skin of the Cane Toad is dry and warty. It has distinct ridges
   above the eyes, which run down the snout. Cane Toads can be grey,
   brown, red-brown or olive in colour, with varying patterns. A large
   parotoid gland lies behind each eye. The ventral surface is cream and
   may have blotches in shades of black or brown. The pupils are
   horizontal and the irises golden. The toes have a fleshy webbing at
   their base, and the fingers are free of webbing.

   Juvenile Cane Toads are much smaller than adults—only 5 to 10
   millimetres (0.2–0.4 in) long. Typically, they have smooth, dark skin,
   although some specimens have a red wash. Juveniles lack the adults'
   large parotoid glands, so they are usually less poisonous. Because they
   lack this key defence, it is estimated that only 0.5% of metamorph Cane
   Toads reach adulthood. The tadpoles are small and uniformly black. They
   are bottom-dwellers and congregate around plants forming schools.
   Tadpoles reach 27 millimetres (1 in) in length, but are smaller, up to
   22 millimetres (0.9 in), under overcrowded conditions.

Ecology and behaviour

   Adult Cane Toads possess enlarged parotoid glands behind the eyes, and
   other glands across the back. When threatened, the Cane Toad secretes a
   milky-white fluid known as bufotoxin from these glands. Bufotoxin
   contains components that are toxic to many animals. There are many
   reported deaths of animals, and even reported deaths of humans, after
   consumption of Cane Toads. A Cane Toad is capable of inflating its
   lungs, puffing up and lifting its body off the ground to appear taller
   and larger to a predator.

   Most frogs identify prey by their movements; Cane Toads can also locate
   food using their sense of smell. They are therefore not limited to
   living prey and can eat plants, carrion, dog food and household refuse
   apart from the normal frog prey of small vertebrates and a range of
   invertebrates. They are active primarily at night, and can range far
   from water.

   The common name of "Marine Toad", and the scientific name Bufo marinus,
   suggest a link to marine life; however, there is no such link. Adult
   Cane Toads are entirely terrestrial, venturing to fresh water to breed,
   and tadpoles have been found to only tolerate salt concentrations
   equivalent to 15% that of sea water. Both eggs and tadpoles are toxic
   to many animals. This toxic protection is lost for a period after
   metamorphosis until the parotoid glands develop. Cane Toads inhabit
   open grassland, generally avoiding forested areas; this inhibits their
   spread in many of the regions in which they were introduced.

   Many species prey on the Cane Toad in its native distribution. These
   include the Broad-snouted Caiman (Caiman latirostris), the Banded
   Cat-eyed Snake (Leptodeira annulata), the eel (family: Anguillidae),
   various species of killifish, the Jungle Perch (Kuhila rubestris), some
   species of catfish (order: Siluriformes) and some species of ibis
   (subfamily: Threskiornithinae). Predators outside the Cane Toad's
   native range include the Whistling Kite (Haliastur sphenurus), the
   Water Rat (Hydromys chrysogaster), the Black Rat (Rattus rattus) and
   the Water Monitor (Varanus salvator). Occasional cases of the Tawny
   Frogmouth (Podargus strigoides) and the Papuan Frogmouth (Podargus
   papuensis) feeding on Cane Toads have been reported. These predators
   possess either a tolerance to the Cane Toad's toxins, or behavioural
   adaptations that allow them to avoid the most poisonous areas of the
   frog as they hunt and consume it.

Reproduction

   The males of the Cane Toad will call near a still water source to
   attract females. The call is a loud, long trill; likened to the sound
   of a small engine or "purr". As with all true toads, the male and
   female undergo inguinal amplexus, in which the male is behind the
   female, and grips her around the waist. The female will then release
   her eggs, which the male covers with sperm.

   Females lay from 4,000 to 36,000 eggs per clutch, and breed at least
   twice per year. They are opportunistic breeders, breeding whenever
   enough water is available. As a result, they have no breeding season.
   The eggs are laid in still or slow flowing water, where the males
   congregate and call in a chorus. Eggs are laid in long strands, usually
   tangled around plants or submerged objects. The eggs are black, and
   surrounded in a clear jelly 4-5 mm in diameter. The duration until the
   eggs hatch is dependent upon the water temperature — lasting from 25
   hours at 34 degrees Celsius (93 Fahrenheit) to 155 hours at 14 degrees
   Celsius (57 Fahrenheit). The development of tadpoles also varies, from
   12 to 60 days.

Distribution

   The Cane Toad is native to the Americas, from the Rio Grande Valley in
   southern Texas to central Amazon and south-eastern Peru. This range
   includes both tropical and semi- arid environments. The density of the
   Cane Toad within its native distribution is significantly lower than
   that of its introduced distribution. In South America, it is recorded
   at densities of 20 adults per 100 metres of shoreline, but in Australia
   the density reaches 1000-2000 adults over the same area.

Introductions

   The Cane Toad has been introduced to many regions of the world,
   particularly the Pacific, for the biological control of agricultural
   pests. Up until 1844, Cane Toads had been introduced into Martinique,
   Barbados and Jamaica. They were unsuccessfully introduced into Jamaica
   to control the rat population.

   In 1920, Cane Toads were introduced into Puerto Rico to control the
   populations of white-grub (Phyllophaga spp.), a pest of sugar cane. By
   1932, the Cane Toad was well established on the island, and the
   populations of white-grubs were dramatically decreased. The decrease in
   the white-grub population was attributed to the Cane Toad, although
   there may have been other factors. The six year period after 1931 (when
   the Cane Toad was most prolific, and the white-grub saw dramatic
   decline) recorded the highest ever rainfall for Puerto Rico. However,
   the assumption that the Cane Toad controlled the white-grub led to the
   large scale introductions throughout many parts of the Pacific.

   There are introduced populations in Australia, Florida, Papua New
   Guinea, the Philippines, the Ogasawara and Ryūkyū Islands of Japan,
   most Caribbean islands and many Pacific islands, including Hawaii and
   Fiji. The introductions generally failed to control the targeted pests,
   most of which were later controlled by the use of insecticides. Since
   then, the Cane Toad has itself become a pest in the host countries,
   posing a serious threat to native animals. The introduction of the Cane
   Toad has had a particularly great effect on Australian biodiversity.
   This is probably due to the large number of species that the Cane Toad
   successfully competes with, and the large areas of open grassland.

   The Cane Toad was successfully introduced into New Guinea to control
   the hawk moth larvae, which were eating the sweet potato crops. Cane
   Toads have since become abundant in rural and urban regions, and have
   not penetrated the forested areas; because most of the native wildlife
   is restricted to forested areas, the Cane Toad has not caused
   significant environmental problems.

Introduction to Australia

   The spread of Cane Toads in Australia from 1940 to 1980 in 5-year
   intervals
   Enlarge
   The spread of Cane Toads in Australia from 1940 to 1980 in 5-year
   intervals

   In attempts to control the native Cane Beetle, 102 Cane Toads were
   introduced to Australia from Hawaii in June 1935. They bred immediately
   in captivity and by August 1935 more than 3000 young toads were
   released in areas around Cairns, Gordonvale and Innisfail in northern
   Queensland. More Toads were released around Ingham, Ayr, Mackay and
   Bundaberg. Releases were temporarily limited due to environmental
   concerns, but resumed in other areas after September 1936. Since their
   release, toads have rapidly multiplied in population and now number
   over 100 million. The population is increasing at a rate of about 25% a
   year. The toads have steadily expanded their range through Queensland,
   reaching the border with New South Wales in 1978 and the Northern
   Territory in 1984. The toads on the western frontier of their advance
   have evolved larger legs; this is thought to be related to their
   ability to travel farther. It is estimated that Cane Toads migrate at
   an average of 40 kilometres (25 mi) a year.

   The long-term impact of toads on the Australian environment is
   difficult to determine. Precipitous declines in populations of the
   Northern Quoll have been observed after toads have invaded an area.
   There are a number of reports of declines in goanna and snake
   populations after the arrival of toads. The preliminary risk assessment
   of Cane Toads in Kakadu National Park stated that the predation of the
   Cane Toad by native wildlife is the greatest risk to biodiversity.
   Other factors, such as competition with native wildlife for resources,
   and the predation of the Cane Toad on native wildlife, were considered
   much lower risk factors. In the Northern Territory, goanna predation on
   cane toads has been linked to a rise in the amount of undamaged salt
   water crocodile eggs. The full impact of this will not be known until
   the crocodiles hatch in March 2007.

   A number of native species have been reported as successfully preying
   on toads. Some birds, such as the Black Kite (Milvus migrans), have
   learned to attack the toad's belly, avoiding the poison producing
   glands on the back of the head. Reports in the Northern Territory
   suggest that a native frog, Dahl's Tree Frog (Litoria dahlii), is able
   to eat the tadpoles and live young of the toad without being affected
   by the poison that often kills other predators. This is believed to
   account for slower than expected infestations of toads in certain areas
   of the Northern Territory. Some snakes have been reported to have
   evolved smaller jaws so that they are unable to swallow large Cane
   Toads which have large quantities of poison.

   As of 2005, ultraviolet light has been used to lure and capture Cane
   Toads for extermination. In June 2006, the University of Queensland
   announced research into a gene to reverse the sex of female Cane Toads.
   This would lead to a population of males, and thus eliminate the
   population. However, this would risk a reverse introduction that would
   wipe out Cane Toads, and possibly other species, in their native range.

In popular culture

   The introduction and migration of the Cane Toad in Australia was
   popularised by the film Cane Toads: An Unnatural History (1988), which
   tells the tale with a humorous edge and is often shown in Environmental
   Science courses. Don Spencer, a popular children's entertainer, sang
   the song Warts 'n' All, which was used in the documentary. The
   documentary was referred to in the Simpsons episode " Bart vs.
   Australia."

   The children's novel Toad Rage, by Morris Gleitzman, is set in
   Australia; it is about a Cane Toad named Limpy who goes on an adventure
   to find out why humans go out of their way to run over Cane Toads. The
   novel has two sequels, called Toad Heaven and Toad Away.

   In the Australian rugby league, the Queensland State of Origin Team are
   informally known as the Cane Toads. Their opponents, the New South
   Wales State of Origin Team, are known as the cockroaches.

   Bufotenin, one of the chemicals excreted by the Cane Toad, is
   classified as a Class 1 drug under Australian drug laws. This is the
   same classification as heroin and cocaine. It is thought that the
   effects of bufotenin are similar to that of mild poisoning; the
   stimulating effect, which includes mild hallucinations, lasts for less
   than one hour. As the Cane Toad excretes bufotenin in very small
   amounts, and other toxins in relatively large amounts, toad licking
   could result in serious illness or death.
   Bufo marinus as purse
   Enlarge
   Bufo marinus as purse

   In Australia, attempts have been made to make use of dead Cane Toads,
   which can number in the thousands and cause hygiene problems. This
   includes processing the carcasses into liquid fertilisers. Their skin
   can also be used as a leather for clothing and accessories.

   In the Australian states where the Cane Toad is common, cruelty towards
   the toad has become popular, such as injuring the animals with golf
   clubs or cricket bats. However, this is not effective, as the force
   exerted by a golf club or cricket bat is not sufficient to kill the
   animals immediately, and their poison remains toxic after their death.
   In April 2005, Dave Tollner, a Northern Territory Member of Parliament,
   called for the legalisation of attacking the Cane Toad, which was
   criticised by many animal and conservation groups. The short film "Cane
   Toad - What happened to Baz?" displays the Australian attitude towards
   the Cane Toad. This film won the "Best Comedy" award at the 2003 St.
   Kilda Film Festival. However, the short relies on humour which
   Australians connect with, and screenings in overseas festivals have
   been more reserved.

   In the Dave Barry novel Big Trouble, a Cane Toad has a small yet
   important role.

   The Cane Toad has been listed by the National Trust of Queensland as a
   state icon of Queensland, alongside the Great Barrier Reef, and past
   icons, the Royal Flying Doctor Service and the backyard mango tree
   (also an introduced species).

   On the website Ezone.com, the game Lenny Loosejocks goes Walkabout has
   a minigame called Cane Toad Explode, where Lenny Loosejocks has been
   commissioned by the Australian government to kill Cane Toads, and is
   awarded money for each toad he kills, varying with the size of the
   toad. The game revolves around Lenny using his ute to try to run over
   as many Cane Toads as possible while avoiding large rocks, which damage
   his car.
   Retrieved from " http://en.wikipedia.org/wiki/Cane_Toad"
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   with only minor checks and changes (see www.wikipedia.org for details
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