Sirens and Dwarf Sirens: Sirenidae

Sirens and dwarf sirens are salamanders with eel-like bodies, no hind legs, and front legs that are extremely small. The jaws are covered with a hard, beaklike structure. The gills are large and stick up from the head like feathers. The body is shaped like a tube with a flat tail. Young sirens have a clear fin on their back that extends to the tip of the tail. On older sirens the part of the fin on the back disappears, and the tail fin that is left becomes solid rather than clear. The legs of sirens have three or four toes that have hard tips.

Sirens and dwarf sirens never leave the water. They get oxygen from water passing through their gills and skin, but they also have lungs. These salamanders live their entire lives with a larva body form. A larva (LAR-vuh) is an animal in an early stage that changes form, or goes through metamorphosis (meh-tuh-MOR-foh-sus), to become an adult. Sirens and dwarf sirens do not respond to the environmental signals that tell other salamanders to start metamorphosis.

Sirens and dwarf sirens are 5 to 40 inches (12 to 100 centimeters) long. Newly hatched sirens and younger larvae (LAR-vee, the plural of larva) are deep black with yellow, red, or silvery white markings. There is a band across the nose and another on the top of the head. Many of these animals have stripes on the body. When the animals are older the markings become dull or disappear.