Nostrils are small round or oval. The toes are blunt and horny. The tongue is large, filling the floor of the mouth, free at back and slightly at sides. The palatine teeth are in two contiguous patches on each side with the anterior patch longer and wider. Dorsum ground color is olive to light gray, some have black spots.
Sides are lighter in color with faint greenish or yellowish spots and dashes.
Venter has bluish gray ground color with numerous small greenish or yellowish flecks or spots. The Greater Siren inhabits most of the Coastal Plain, favoring muddy, weed-choked ditches, swamps, ponds, large lakes and streams. Seldom seen during the day, these creatures eat crustaceans, mollusks, worms, insects and algae. They develop large fat deposits to allow survival up to several years without feeding, as when stranded by drought in their deep burrows. Larvae are about 16mm at hatch.