Sometimes the term toad is restricted to the so-called true toads, members of the family Bufonidae. These are characterized by warty skins and prominent parotid glands behind the eyes and as a group are the most terrestrial of the order. In most the feet are only slightly webbed. They range in length from about 1 to 7 in. (2.5–18 cm). Most species belong to the genus Bufo; members of these species spend much of the time on land, generally near water. They generally live in cool, moist places and absorb moisture through the skin. The white fluid that they exude through the skin, as well as from the parotid glands, is very poisonous and causes intense burning if it comes in contact with the eyes or mouth; however, contrary to an old belief, it does not cause warts. Toads, like frogs, move on land by jumping and feed on insects and grubs. Also like frogs, they usually lay their eggs in water in strands of jelly. Fertilization is external. The egg hatches into a tadpole , a gilled, aquatic, larval toad that undergoes metamorphosis into the adult.
There are about a dozen Bufo species in the United States, among them the common American toad ( Bufo americanus ), Fowlers toad ( B. fowleri ), of the E United States, and the red-spotted toad ( B. punctatus ), of the Southwest. The cane, marine, or giant toad ( B. marinus ), a large toad native to Central and N South America, was widely introduced in warm regions (Caribbean, Pacific, Australia, and Florida) to control agricultural pests but is now regarded as an invasive species; they compete with and prey on native species, and their toxic secretions can kill predators.
The spadefoot toads, burrowing toads of the family Pelobatidae, are represented in the United States by several species of the genus Scaphiopus. Toads are classified in the phylum Chordata , subphylum Vertebrata, class Amphibia, order Anura.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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