These North American microhylids (Family: Microhylidae) are distinguished from true toads (genus Bufo), and other anurans by their moist, smooth skin, their lack of eardrums or tympana, their distinguishable squat body shape, and the unique fold of skin superior to their eyes.

[9] Gastrophryne carolinensis toads have a typical teardrop-shaped body that is characteristic of members of the family Microhylidae.

[11][12] Directly behind the eyes, resting on the toad's neck, is a distinctive skin fold evolved for protection from ant bites while feeding.

The species resides in the southeastern quarter of the US, extending from Missouri and eastern Texas and from southern Maryland to the Florida Keys, as well as in an isolated colony in Iowa.

[20] Although they live in a broad range of habitats and are rather ubiquitous, their most important environmental variables must include moisture and shelter.

[1] The members of this species tend to discount dry areas and mountains, though some may live in near desert-like conditions.

[22] General habitat types include: The species' population is currently large throughout most of its range, and also in many suburban locations.

[3] A male can be distinguished from a female during breeding season due to the visibility of a dark-pigmented vocal sac on his throat.

Breeding males also exhibit enlarged tubercles on the chin, as well as a visible anterior edge of the lower jaw.

The toad species will breed in deep water only if it is covered with a dense mat of floating vegetation or debris.

[20] They can also call the female while sitting on a bank, or on rainy nights while buried in the damp sand with only their head and vocal sac exposed.

[3] If they are reproducing in ephemeral aquatic habitats, the male toad calling will position himself to be completely underwater with only his head exposed.

[14] Unlike other frog and toad species, G. carolinensis does not exhibit the typical trill sound in their mating call.

In the south, April to October rains initiate their breeding season, or midsummer in areas farther to the north.

[30] A study in 2013 identified 4,859 individual ants retrieved from stomachs of 146 eastern narrow-mouthed toads in Florida scrub.

[11][25] These various arthropods make up to 75% of their diet, though other prey may include small snails, spiders, mites, collembolans, and lepidopterans.

However, Gastrophryne carolinensis has been observed using irritating and noxious integumentary secretions as a defense mechanism to discourage predators when caught.

[33] Gastrophyryne carolinensis toads are weak jumpers, thus either run or move by short and rapid hops.

Other known predators include the glossy watersnakes (Liodytes rigida), the eastern cottonmouth (Agkistrodon piscivorus), and the cattle egret (Bubulcus ibis).

This particular toad species avoids predators by burrowing, seeking cover, and/or nocturnal activity patterns.

Based on observances of the different developmental features of the ilium between G. carolinensis and G. olivacea, the two species could have differentiated from the early Miocene.