Western Narrow-Mouthed Toad

Gastrophryne olivacea
Other Common Name
Great Plains Narrow-Mouthed Toad

Microhylidae (narrow-mouthed toads) in the order Anura (frogs)


Like the eastern narrow-mouthed toad, this species has a plump body, small pointed head, and a fold of skin behind the eyes. This species is typically uniform in color, ranging from tan to gray or olive green, with few markings. The belly is white. Call is a high-pitched short peel sound that sounds similar to the buzz of a bee and lasts 1–4 seconds.

Similar species: The eastern narrow-mouthed toad has a darker overall color as well as a pattern of dark markings on the back. Also, its call is a bleating, nasal baaaa, like the cry of a lamb, and is nothing like the call of the western narrow-mouthed toad. These two species often occur in the same areas, but their mating calls are so different they don’t interbreed and hybridize.


Length (snout to vent): 7/8 to 1 1/2 inches.

Western Narrow-Mouthed Toad

Image of a western narrow-mouthed toad
Audio of a Western Narrow-Mouthed toad.
Habitat and conservation

This species prefers grasslands, rocky and wooded hills, and areas along the edge of marshes. They spend most of their time hiding in loose soil, under rocks, boards, logs, or other objects, and have been known to hide in animal burrows.


Mostly ants. This species has evolved a toxic skin secretion that may protect it from ant bites, since it tends to sit on anthills while eating its preferred food.

image of  Western Narrow-Mouthed Toad Great Plains Narrow-Mouthed Toad
Distribution in Missouri

Western Missouri and along the Missouri River floodplain.


This species used to be called the Great Plains narrow-mouthed toad.

Life cycle

Breeding occurs from late May to early July. Warm, heavy rains stimulate males to congregate at ditches, temporary ponds, flooded fields, or pools in wooded areas. Special glands on the male’s belly secrete a gluelike substance that sticks the mating pair together. The female lays up to 645 eggs as a film on the water surface. These hatch in 2–3 days, and the tadpoles transform into froglets 20–30 days later.

Human connections

As predators, these amphibians help control populations of many insects that are pests to humans. Additionally, their weirdly beautiful, strange-sounding choruses add to the magic of a Missouri evening.

Ecosystem connections

Narrow-mouthed toads are predators that help keep populations of ants and other insects in balance. They, and especially their eggs, tadpoles, and young toadlets, become food for both aquatic and terrestrial predators ranging from water bugs to fish to grackles to raccoons.