The colour of the smooth skin of the eastern narrowmouth toad (Gastrophryne carolinensis) is highly variable within and between populations, and may be grey, brown, brown-yellow or reddish (3). Some individuals may have a wide, wavy, dark band that runs along the middle of the back (2) (3). The underside of this amphibian is darkly coloured, patterned with lighter specks (2) and unlike the upper surface, may have a slightly rough appearance (3). The body is pear-shaped (3) and the head is small (2) with a sharply pointed snout (2) (3) and a red oval on either side, which are located where the hearing organs are internally positioned (2). The toes are not webbed (2) (3) and there are horn-like lumps on the rear feet, which are used for digging (2).
The female eastern narrowmouth toad is generally larger than the male, although its physical appearance is similar (2) (4). During the breeding season, it is easy to distinguish the sexes from each other, as the male has a darkly coloured vocal sac on its throat, which is especially prevalent when it calls (2) and it also develops enlarged tubercles on its chin and jaw (4). When in the larval tadpole stage of life, this species is mostly black (2) (3), occasionally with a white stripe along each side of the tail. When viewed from above, the body of the tadpole is rather square, but with rounded corners. The body is relatively flat when viewed from the side (3).
The mating call of the eastern narrowmouth toad is often compared to a bleating lamb (2) (3) (4), although it is more nasal and has a slightly higher pitch (2).
- Adult body length: 2.5 - 3.5 cm (2)