| Great
Plains Narrowmouth Toad |
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Great
Plains Narrowmouth Toad (Gastrophryne olivacea)
By J. Eric Wallace, Nongame Biologist |
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Scientific
Name:
Gastrophryne olivacea. From the Greek gaster meaning belly and phryne meaning
toad, possibly referring to the pot-bellied appearance, and from the Latin
oliva meaning olive, referring to the general coloration. |
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Description:
Small; up to 1.5 inches long; females usually larger than males. Relatively
stout body tapers to a narrow, pointed, flattened head. Smooth, tough
body skin forms a fold along back of head. Eyes resemble small, black,
glass beads. Legs short, forelegs slender when compared to stout, stubby
hind legs. No webbing between toes. Dorsal coloration olive-brown,
light tan, or grayish, with at least a few dark spots. Distinct bars
or blotches usually present across thigh and calf. Underside usually
immaculate, but strongly mottled in some Arizona upland populations.
Males have dark throat, especially during breeding season. Young have
distinctive, dark, leaf-like pattern on back, fading with age. |
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Habitat:
In Arizona, from desert grassland (mesquite) to oak woodland. Found in
deep, moist crevices or burrows, often with various rodents, and under
large flat rocks, dead wood, and other debris, near streams, seeps,
and ephemeral pools. More terrestrial than aquatic in habits. |
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Distribution:
Ranges throughout most of the Great Plains to northern Mexico, east to
the Gulf of Mexico, and west to the Sea of Cortez, then north into
south-central Arizona. Limited occurrence in Arizona, mainly on the
Tohono O'odham and Gila Indian reservations, and in and near the Patagonia
and Pajarito mountains. From sea level to approximately 4,100 feet. |
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Biology:
These inconspicuous little toads live a primarily subterranean lifestyle,
surfacing at night, usually after heavy summer rains, to breed and
occasionally to feed. During these wet periods, males make their way
to pooled water and commence calling. At a distance, their breeding
chorus has been likened to the "baaing" of sheep and, in
closer proximity, to the buzzing of honeybees. Upon attracting a mate,
the male grasps her from behind and "glues" himself to her
back with a viscous skin secretion, which ensures a good connection
and reduces the possibility of disturbance from rival males. The eggs,
laid in a film at the water's surface, are fertilized as they are laid.
Narrowmouth toads develop quickly, growing from egg to toad in 24 to
50 days.
This species is myrmecophagous (ant-eating), which may account for the
tough skin and the fold of skin across the neck, both affording protection
from ant bites and stings. Narrowmouths share burrows with tarantulas,
lizards, moles, and many other creatures. Once, in the Texas hill country,
I overturned a large flat rock and revealed a narrowmouth co-habiting with
such dangerous bedfellows as two scorpions and a black widow spider. |
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Status:
The Great Plains narrowmouth toad is included on the Department's list
of Threatened Native Wildlife in Arizona (1988) as a candidate species
due to known and suspected habitat threats, but is neither listed nor
proposed for listing by the U.S. Fish and Wildlife Service as endangered
or threatened. This species is abundant across most of the Great Plains. |
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Management
Needs:
Recent Heritage-funded surveys have confirmed that Great Plains narrowmouth
toads still occur at most historical localities in Arizona. This information
suggests that no active management is necessary, although continued monitoring
would help to ensure the continued presence of this tiny toad among our
native fauna. |
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