The greater siren (Siren lacertina) is an eel-like amphibian. The largest of the sirens and one of the largest amphibians in North America, they measure around 1.5 cm (0.59 in) in length upon hatching and then grow to lengths ranging from 18 to 97 cm (7.1 to 38.2 in).[2][3][4] Weight can range from 55 to 1,000 g (1.9 to 35.3 oz).[5][6] They range in color from black to brown, and have lighter gray or yellow underbellies.