Toads

TOADS, tailless amphibians, family Bufonidae, have a well-developed tongue (Phaneroglossa), their coracoids are movably connected to the sternum (Arcifera), and they lack teeth. The clumsy body with thick legs is covered with a warty skin. In the adult state, most toads live on land. They go into the water for spawning. Diagram of the arrangement of derivatives of the gill slits: I, II, III, IV, and V—gill or pharyngeal pouches; a and b—medial and lateral parts of the thyroid gland anlage; post-branchial body; c₁—anlage of the thymus gland of the III pharyngeal pouch (main part); c₂—anlage of the thymus gland of the IV gill pouch (inner part of the thymus gland); d₁, d₂—lower and upper epithelial bodies; d₃—anlage of the epithelial V pharyngeal pouch (not yet embryologically proven); e—anlage of tonsillae. (After Aschoff.) spawn. Active at night, when they emerge to catch prey, which consists of insects, spiders, some mollusks, and worms. About 140 species of toads are known. Toads are distributed worldwide, but are fewer in cold countries than in warm ones. The common, or grey toad—Bufo vulgaris, is found in Europe up to 66° N. lat.; it lives in damp and dark places (cellars, sheds, under stones, roots, etc.). It hibernates by burying itself in the ground. The green toad (Bufo viridis) lives in forests, fields, kitchen gardens, orchards, and is found in villages and towns, where it often climbs into human dwellings. In steppes, it is found in gopher burrows. It is distributed in northern Europe, Asia, and northern Africa. Toads are beneficial animals because they feed on various insects, including those harmful to agriculture; therefore, toads deserve protection. In England, they are bought by gardeners and released into gardens. But toads are also poisonous animals. Their skin contains many simple saccular poison glands that accumulate behind the eyes into "parotids." However, toads have no piercing or wounding apparatus. For defense, for example, the natterjack toad contracts its skin, thereby covering itself with an unpleasant-smelling white foam—the secretion of the poison glands. Both the odor of the poisonous secretion and its irritating effect on mucous membranes serve toads as a reliable defense against enemies. The active principle of toad poison is buphotalin (see Buponin, Buphotalin, Aga). Toad poison is insensitive to the action of radium rays in doses that destroy snake venom. Toads are little sensitive to the action of alkaloids—strophanthin, helleborin, scillopicrin, physostigmine, and muscarine. The skin secretion of salamanders is toxic to toads. Toads have been used in folk medicine since ancient times. In China, toad "Sen-so" is used as a cardiac remedy and as a roborans (see Amphibians).