Possible Former Range in
California: Red
Dot-locality range map
Listen to this toad:
One short call
More sounds of
Bufo microscaphus
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| Adult, Washington County, Utah |
Adult, Washington County, Utah |
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| Adult, Washington County, Utah |
Adult, Washington County, Utah |
Adult, Washington County, Utah |
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| Adult, Washington County, Utah |
Underside of adult |
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Adult, Yavapai County, Arizona |
Adult, Arizona. Arizona-Sonora Desert Museum
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Habitat |
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Possible habitat along the Colorado River near Needles, San Bernardino County |
Possible habitat near the Colorado River near Fort Mojave, San Bernardino County |
Short Videos |
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Several male Arizona Toads calling and interacting at night at the edge of a small creek next to a river in Washington County, Utah, including two examples of a male attempting amplexus with another male who then makes release calls. Canyon Treefrogs can be heard in the background.
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A short example of a male calling at night. |
Several Arizona Toads seen hanging around the edge of a small creek at night in Washington County, Utah. |
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Description |
| Size |
| Adults are 2 - 3 inches from snout to vent ( 4.6 - 8.6 cm). |
| Appearance |
| A plump, stocky toad with dry, skin with low warts and few tubercles. No cranial crests. Oval, widely separated parotoid glands that are pale toward the front. Pupils are horizontal. Color is usually gray, but can be beige, pale yellow, pink, rusty, and brown. No stripe down the middle of the back. Often paler on front of parotoids, upper eyelids, and central upper back. Whitish below, with no spots or mottling. Male and female throats are pale. Young are salmon-colored or light olive with reddish warts. Moves by hopping instead of walking. (Has fewer warts and spots and tubercles than related B. californicus.) |
| Voice (Listen) |
| A fast high-pitched trill averaging 5.7 seconds in length, rising in pitch, and ending abruptly. Calls are made at night. |
| Behavior |
Nocturnally active, remaining underground in the daytime, but occasionally seen moving about in daylight or resting at the edge of breeding pools in the breeding season.
A typical toad: slow moving, often using a walking or crawling motion along with short hops. Like most toads do for defense, this toad relies on parotoid glands and warts which can secrete a poison that deters some predators. |
| Diet |
| Diet consists of a variety of invertebrates. Prey is located by vision, then the toad lunges with a large sticky tongue to catch the prey and bring it into the mouth to eat. |
| Reproduction and Young |
Breeding is aquatic. Fertilization is external. Breeding takes place from early to Late February at some locations, and late March to early April at higher-elevation locations, ending as late as July. Breeding is not dependant on rainfall, but by warming temperatures and water levels. Spring flooding delays breeding. Breeding may occur for 10 - 12 days at a location, then stop due to rain and floods, and continue again following warmer drier weather.
Breeding sites are shallow stream edges and side pools with minimal current. Males gather at a breeding site and make an advertisement call to attract females, but many males are satellite breeders, either searching for females, or waiting and grabbing a female who is attracted to another male's call.
Egg strings are laid on the bottom of pools. An average of 4,500 eggs per clutch has been estimated. Eggs hatch in 3 - 6 days. Tadpoles metamorphose in 3 - 4 months depending on varying environmental conditions. Predation and flooding can cause high tadpole mortality. |
| Range |
The overall range of this toad is fragmented, from the Colorado River drainage near Fort Mojave, east across central Arizona into western New Mexico, and around the area where the Nevada, Utah, and Arizona borders meet.
In his 1972 book California Amphibians and Reptiles, Robert Stebbins states that this toad is present at the Colorado River near Needles, but I have not yet found any records of museum specimens from that area of California. In the range map of his subsequent 2003 field guide, Stebbins does not indicate that B. microsacphus occurs (or even formerly occured) in California. Many sources do show the range of this toad extending into California, as in this US Forest Service map, and this IUCN map.
I list the species as formerly present in California due to these and other indications of its occurance in California across the Colorado River from known populations around Fort Mojave, Arizona. More recent range maps which do not show this species occuring in California are interpreted as illustrating that the species no longer occurs in the state due to habitat alteration. |
| Habitat |
Inhabits riparian areas from lowlands near the Colorado River drainage in California, into uplands and pine-oak woodland.
From 600 - 6,000 ft. (190 - 1,829 m.) |
| Taxonomic Notes |
In 1998 B. microscaphus was split into two species, B. californicus, and B. microscaphus. Some sources still list this toad as a subspecies of Bufo microscaphus, Bufo microscaphus microscaphus.
This toad has been renamed Anaxyrus microscaphus, but this nomenclature is not yet standard. |
| Conservation Issues (Conservation Status) |
| I can't find any information about the current presence and status of this toad in California. It has been estimated to be absent from 75% of its historic range, but others note that a general decline has not occurred throughout Arizona. Impoundments which restrict the flow of stream water, create quiet waters which are more favored for breeding by a competing toad species, B. woodhousii, with which B. microscaphus hybridizes. Introduced predators, land alteration, and human recreational land use may also contribute to declines. |
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Taxonomy |
| Family |
Bufonidae |
True Toads |
| Genus |
Bufo |
True Toads |
| Species |
microscaphus |
Arizona Toad
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Original Description |
Cope, "1866" 1867 - Proc. Acad. Nat. Sci. Philadelphia, Vol. 18, Oct., p. 301
from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
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Meaning of the Scientific Name |
Bufo - Toad
microscaphus - mikros - Greek - small
skaphis Greek - shovel - refers to this toad's tarsal spade
from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
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Alternate Names |
Formerly called Bufo microscaphus microscaphus
Anaxyrus microscaphus
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Related or Similar California Frogs |
Bufo californicus - Arroyo Toad
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More Information and References |
Natureserve Explorer
California Dept. of Fish and Game
AmphibiaWeb
Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.
Behler, John L., & F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.
Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995. |
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The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game.
This toad is not on the Special Animals List, meaning there are no significant conservation concerns for it in California according to the Dept. of Fish and Game. However, this might be because they do not recognize it as a distinct species. If it still occurs in California, this toad is definitely at risk.
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Organization
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Status Listing
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| U.S. Endangered Species Act (ESA) |
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| California Endangered Species Act (CESA) |
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| California Department of Fish and Game |
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| Bureau of Land Management |
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| USDA Forest Service |
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| Natureserve Global Conservation Status Ranks |
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World Conservation Union - IUCN Red List
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