TADPOLE

also called polliwog aquatic larval stage of frogs and toads. Compared with the larvae of salamanders, tadpoles have short, oval bodies, with broad tails, small mouths, and no external gills. The internal gills are concealed by a covering known as an operculum. Most tadpoles are vegetarians, although those of some species are carnivorous or even cannibalistic. Tadpole metamorphosis follows a pattern of gradual development of fore- and hind-limbs, resorption of the tail, shortening of the intestine, disappearance of the gills, and development of lungs. Upon completion of metamorphosis, the tadpole emerges onto land as a young frog or toad.