A black toad is an amphibian found only in a small, high desert region in the United States. The black toad, also called the Inyo toad and Deep Springs Valley toad, lives in remote marshes near dry lake beds in Inyo County, California. Its scientific name, Bufo exsul, refers to its isolated habitat, because bufo means toad and exsul defines exile or refugee in Latin.
This toad survives in one of the smallest regions of any amphibian found in North America. Its habitat covers several natural springs at elevations between 4,900 feet (1,450 meters) and 5,600 feet (1,700 meters) between two mountain ranges in the Deep Springs Valley. A small number of black toads were once discovered in the Death Valley National Park of California, but wildlife officials believe they were introduced to the area by man.
Conservation officials also released these toads into Cottonwood Springs in the Owens Valley of California in the early 1960s, but they did not survive. This area is just a few miles away from the black toad’s natural habitat. This species is not considered endangered, but it could become threatened during a prolonged drought.
The black toad depends on water more than other toads, spending much of its time crawling and walking through shallow marshes and muddy flats. It retreats underground during the winter, emerging in late spring or early summer. When the temperature rises, the black toad only comes out at night to feed.
This dark, black toad is typically marked with lighter splotches that range from white to light tan. A light stripe runs from its head to its tail across a warty skin surface. The black toad emits a poisonous chemical through the skin to ward off predators.
Mud flats camouflage the toad when it seeks food. It uses its sticky tongue and a lunging movement to catch small insects. It is also capable of short hops while traveling through marshy wetlands. The black toad might leave the water to seek bugs in dry, sandy areas where insects feed on vegetation.
This toad does not croak because it lacks vocal sacs in the throat, but it uses a chirping sound as a mating call. During late March and early April, male toads might fight over a potential mate by thrashing in shallow water. The female lays eggs attached to a wispy string near the water’s edge, where they can be hidden from predators by vegetation.
Eggs hatch within five days into larvae. It might take up to five weeks for tadpoles to develop. The newborn toads appear olive green until they mature. California conservation officials use cattle grazing in the area to keep down vegetation that could choke out the toad. Droppings from cattle also attract insects the toads rely on as food.