The South American lungfish is an eel-like species that grows to a length of about 1.5 metres. It is well-adapted to swamps and the weedy margins of rivers and lakes, where oxygen levels in the warm, still waters are often low. It obtains oxygen through a pair of lungs, as well as through its gills, coming to the surface frequently to gulp air. In times of drought, it burrows into the mud, where it stays until the rains return.