Though eel-like in appearance (with long, slimy bodies, vertically-flattened paddle-like tails and internal gills that are retained even in adulthood) the three species of amphiumas are actually large salamanders adapted to a fully-aquatic way of life, and can be distinguished from one another by the number of toes at the end of their tiny vestigial legs (either three, two, or a single small nub of a toe.) Endemic to the southern USA, Three-Toed Amphiumas live mainly in densely vegetated swamps, lakes and slow-moving rivers where they spend much of the day hidden in burrows or among submerged plants, emerging at night to prey on worms, aquatic insects and smaller vertebrates which they catch using two rows of short, sharp teeth. Although they spend much of their lives underwater and are extremely vulnerable to predators and environmental conditions when not submerged Three-Toed Amphiumas possess simple lungs in addition to gills and may crawl to new bodies of water during particularly rainy nights, although when faced with prolonged drought or a lack of food they may also retreat underground and enter a dormant state until conditions improve.