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true toad
The true toads are the family Bufonidae, members of the order Anura (frogs and toads). They are the only family of anurans in which all members are known as "toads", although some may be called frogs (such as harlequin frogs). The bufonids now comprise more than 35 genera, ''Bufo'' being the most widespread and well known.
==Characteristics==
True toads are widespread and are native to every continent except Australia and Antarctica, inhabiting a variety of environments, from arid areas to rainforest. Most lay eggs in paired strings that hatch into tadpoles, although, in the genus ''Nectophrynoides'', the eggs hatch directly into miniature toads.
True toads are toothless and generally warty in appearance. They have a pair of parotoid glands on the back of their heads. These glands contain an alkaloid poison which the toads excrete when stressed. The poison in the glands contains a number of toxins causing different effects. Bufotoxin is a general term. Different animals contain significantly different substances and proportions of substances. Some, like the cane toad ''Bufo marinus'', are more toxic than others. Some "psychoactive toads", such as the Colorado River toad ''Bufo alvaris'', have been used recreationally for the effects of their bufotoxin.
Male toads possess a Bidder's organ. Under the right conditions, the organ becomes an active ovary and the toad, in effect, becomes female.〔Brown, Federico D., Eugenia M. Del Pino, and Georg Krohne. "Bidder's organ in the toad Bufo marinus: Effects of orchidectomy on the morphology and expression of lamina-associated polypeptide 2." Development, Growth & Differentiation. Wiley Online Library. Volume 44, Issue 6, pages 527–535, December 2002.〕
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