CaliforniaHerps.com

A Guide to the Amphibians
and Reptiles of California


Black Toad - Anaxyrus exsul

(Myers, 1942)

(= Bufo exsul)
Click on a picture for a larger view



Black Toad Range Map
Range in California: Red
Introduced population: Blue



Listen to this toad:

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One short call



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Black Toad Black Toad Black Toad
Adult, Inyo County Adult, Inyo County Adult, Inyo County
Black Toad Black Toad Black Toad
Adult, Inyo County Adult, Inyo County Adult, Inyo County
Black Toad Black Toad Black Toad
Adult, Inyo County Adult, Inyo County Adult, Inyo County
Black Toad Black Toad Black Toad
Adult, Inyo County Adult underside, Inyo County Adult, Inyo County
Black Toad Black Toad Black Toad
Adult, Inyo County Adult, Inyo County Adult, Inyo county,
© 2005 John Stoklosa
  Black Toad  
  Newly metamorphed juvenile, Inyo County. © Ceal Klingler
 
     
Breeding, Eggs, and Tadpoles
Black Toads Black Toad Eggs Black Toad Tadpoles
Male and female in amplexus Eggs, Inyo County © Mark Gary

Recently-hatched tadpoles, Inyo County


See more pictures and videos of breeding Black Toads,eggs and tadpoles here,

Listen to their sounds here.



Habitat
Black Toad Habitat Black Toad Habitat Black Toad Habitat
Habitat, Inyo County Habitat, Inyo County Distant view of Deep Springs Valley,
Inyo County
Black Toad Habitat Black Toad Habitat Black Toad Habitat
Deep Springs Valley, Inyo County, showing dry lake and springs in distance.
Distant view of another spring in
Deep Springs Valley
Black Toads blend in well with this dark mud that makes up much of their habitat, especially at night. (There are no toads in this picture.)
Black Toad Habitat    
View of toad habitat, Inyo County
   
     
Short Videos
Black Toad Black Toad Black Toads
Black Toads crawling around in the water at night. A Black Toad lunges with its sticky tongue extended, trying to catch something to eat. A solo male approaches a male in amplexus who gives an encounter call.
Black Toads Black toads Black toads
This video shows some of the sounds and activities of Black Toads on the breeding grounds. A group of male toads thrash around in the water trying to wrestle away a female away from another male. Non-stop ultimate toad-fighting action with a gang of toads trying to steal away females from other males, chasing them around the pond.
     
Description
 
Size
Adults are 1.75 - 3 inches from snout to vent (4.4 - 7.6 cm). (Stebbins, 2003)

Appearance
The skin is dry and warty, but relatively smooth for a toad.
No cranial crests are present.
Parotoid glands are oval.
Color and Pattern
Dark, almost solid black above, with light wavy marks and speckles.
Usually has a light stripe down the middle of the back.
Belly is light and heavily blotched with black.
Male/Female Differences
Throat is pale, less spotted on males than on females.
Young
Young are olive colored.

Life History and Behavior
Activity
Active from March to September, hibernating in rodent burrows near the water during winter.
Diurnal and crepuscular becoming mostly nocturnal during the heat of late spring and summer.
More aquatic than most toads, Black Toads spend most of their time in shallow marshy areas, but they can also be found on dry, sandy soil around springs, foraging among grassy tussocks.
Movement
Typical of toads, this one moves slowly, often using a walking or crawling motion along with short hops.
Defense
As most toads do for defense, this toad relies on parotoid glands and warts which can secrete a poison that deters some predators. They also swim to the bottom to avoid danger.
Diet and Feeding
Eats a variety of small 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.
Breeding
Breeding is aquatic.
Fertilization is external, with the male grasping the back of the female and releasing sperm as the female lays her eggs.

The reproductive cycle is similar to that of most North American Frogs and Toads. Mature adults come into breeding condition and move to the water. Males and females pair up in amplexus in the water where the female lays her eggs as the male fertilizes them externally. The adults leave the water and the eggs hatch into tadpoles which feed in the water and eventually grow four legs, lose their tails and emerge onto land where they disperse into the surrounding territory.

Mating and egg-laying occurs from late March into  April or May, taking place in shallow water with vegetation to protect eggs and tadpoles.
Eggs
Eggs are laid in shallow waters bordering the larger wetlands.
Eggs are laid in strings which are entwined in aquatic plants on or just below the surface.
Eggs hatch in 5 days.
Tadpoles and Young
Larvae transform 3 - 5 weeks after hatching.
Tadpoles do not overwinter.
Transformed juveniles remain in shallow marshy areas with the adults.
Voice (Listen)
Black toads do not have vocal sacs and do not make an advertisement call. They produce only a weak chirping release or territorial call, similar to the call of the California Toad but higher in pitch. Calls are made during the day and at night. Since it is not made to attract distant females, the call is not very loud.

Habitat
Inhabits springs and marshes in an isolated desert basin between the Inyo and White Mountains. Toads are sometimes found in surrounding grasses. The vegetation around these springs is sparse and conditions are very dry with sandy soil.

Geographical Range
Endemic to California. This toad has one of the smallest ranges of any North American Amphibian. It occurs naturally only in a few spring systems in Deep Springs Valley, Inyo county.

According to a CA Dept. of Fish & Game report, In 1998, a small introduced population of B. exsul was found in the Saline Valley in Inyo County, in Death Valley National Park. A study determined that these toads originated from springs in Deep Springs Valley.

In 1961, Black toads were released at Cottonwood Springs in the Owens Valley, about 19 miles from Deep Springs Valley, but they have not been reported from that location again.

A specimen collected from Batchelder Spring on the west side of Westgard Pass was also most likely introduced to that location.
Elevational Range
Occurs at elevations of about 4,900 ft. to 5,600 ft. (1,450 to 1,700 m). (Stebbins, 2003)

Notes on Taxonomy
Related to Anaxyrus boreas, but thought to have been isolated from that species for at least 12,000 years.

Formerly included in the genus Bufo. In 2006, Frost et al replaced the long-standing genus Bufo in North America with Anaxyrus, restricting Bufo to the eastern hemisphere. Bufo is still used in most existing references.


Alternate and Previous Names (Synonyms)

Inyo Toad
Deep Springs Toad

Bufo exsul - Black Toad (Stebbins 1985, 2003, Stebbins & McGinnis 2012)
Bufo boreas exsul - Black Toad (Stebbins 1954, 1966)
Bufo exsul - Black Toad (Wright and Wright 1949)
Bufo boreas halophilus - California Toad (Storer 1925)

Conservation Issues  (Conservation Status)
The population of Black Toads appears to be stable. This toad is listed as threatened because it occurs only in a small isolated population that is restricted to very limited and specialized habitat. If the springs that it depends on were to dry up, or if a disease or predator were introduced, the toad would most likely become extinct.

Deep Springs College
and the California Department of Fish and Game cooperate to protect Black Toad habitat by managing water diversions and vegetation around the springs. The college grazes cattle in the winter, when the toads are hibernating, which cuts back vegetation that would choke off toad habitat. Cattle droppings also support insect populations on which the toads feed. In this way, the cattle perform a function once performed by now-absent native grazers such as bighorn sheep and antelope.
Taxonomy
Family Bufonidae True Toads Gray, 1825
Genus Anaxyrus North American Toads Tschudi, 1845
Species exsul Black Toad

(Myers, 1942)
Original Description
Myers, 1942 - Occ. Papers Mus. Zool. Univ. Michigan, No. 460, p. 3, pl. 1 and 2

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Bufo - toad
Anaxyrus - Greek - A king or chief
exsul -Latin for exile, refugee - refers to the isolated distribution of this toad

Taken in part from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Frogs
Anaxyrus boreas halophilus

More Information and References
California Department of Fish and Wildlife

AmphibiaWeb

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Macey, J. Robert and Theodore Papenfuss."Herpetology." The Natural History of the White-Inyo Range Eastern California.
Ed. Clarence Hall. University of California Press, 1991.

Thelander, Carl G., editor in chief. Life on the Edge - A Guide to California's Endangered Natural Resources - Wildlife. Berkeley: Bio Systems Books, 1994.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Amphibians of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Elliott, Lang, Carl Gerhardt, and Carlos Davidson. Frogs and Toads of North America, a Comprehensive Guide to their Identification, Behavior, and Calls. Houghton Mifflin Harcourt, 2009.

Lannoo, Michael (Editor). Amphibian Declines: The Conservation Status of United States Species. University of California Press, June 2005.

Storer, Tracy I. A Synopsis of the Amphibia of California. University of California Press Berkeley, California 1925.

Wright, Albert Hazen and Anna Wright. Handbook of Frogs and Toads of the United States and Canada. Cornell University Press, 1949.

Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995.
Conservation Status

The following status listings are copied from the 2017 Special Animals List and the 2017 Endangered and Threatened Animals List which are published by the California Department of Fish and Wildlife.

If no status is listed here, the animal is not included on either CDFW list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status, you can go to the NatureServe and IUCN websites to check their rankings.

Check here to see the most current complete lists.


Special Animals List Notes:

1) Formerly Bufo exsul; Frost, Grant, Faivovich, Bain, Haas, Haddad, De Sá, Channing, Wilkinson, Donnellan, Raxworthy, Campbell, Blotto, Moler, Drewes, Nussbaum, Lynch, Green & Wheeler (2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History 297: 1-370) placed this species in the genus Anaxyrus (Tschudi, 1845). The standard common name remains black toad.
Organization
Status Listing
NatureServe Global Ranking G1 Critically Imperiled—At very high risk of extinction due to extreme rarity (often 5 or fewer populations), very steep declines, or other factors. Imperiled—At high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors.
NatureServe State Ranking S1

Critically imperiled in the state because of extreme rarity (often 5 or fewer populations) orbecause of factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.

U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) ST - 6/27/71 Threatened
California Department of Fish and Wildlife FP Fully Protected
Bureau of Land Management S Sensitive
USDA Forest Service S Sensitive
IUCN VU Vulnerable
 

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