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 frogs, 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.
The Cane Toad is a very large frog, 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.[3] 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).[4] 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 Toad 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.[5] 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.
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,[6] 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 that of 15% of sea water.[7] 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)[8] feeding on Cane Toads have been reported. These predators require 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.
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 puttering 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 4-5mm in diameter. The duration until the eggs hatch is dependent upon the water temperature — lasting from 25 hours at 34 degrees Celsius (93.2 Fahrenheit) to 155 hours at 14 degrees Celsius (57.2 Fahrenheit). The development of tadpoles also varies, from 12 to 60 days.
There you go.
2006-08-15 05:17:24
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answer #5
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answered by punk4emo 2
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