Deep Springs Valley, a patchwork of private, public, and state lands sandwiched between the White and Inyo Mountain Ranges, is home to the only known population of black toads. The black toad has one of the narrowest ranges of any North American anuran, which puts the species in a potentially hazardous position, especially given that its necessary water environment is bordered by desert. Despite two population studies indicating a stable population. A 1978 census that was conducted in some of the toad’s range put the number of toads there at 7,897 to 9,744. In 1999, we conducted a population study in the same location and calculated 8,419 toads.
California has two statuses for the black toad: Fully Protected and Threatened. The Department’s capacity to manage toad habitat profitably is actually reduced by the Fully Protected designation, but we and our partners can still restore some habitat thanks to creative management strategies. Being mostly aquatic, toads only leave spring flow regions when migrating to other springs. The toad’s genetic fitness is maintained by this crucial meta-population activity, which is made possible by the connectedness between springs and streams via desert washes.
Habitat and Distribution
California’s eastern border is the only place where black toads (Anaxyrus exsul) can be found. Within a 15 hectare region, the entire population is dispersed in different places. They can be found as far south in Deep Springs Lake and as far north as Antelope Spring. A dispersed population can also be found close to Salt Lake City, Utah. They are more frequently seen in places with plenty of flora and shallow water. They pick places like bogs and marshes for breeding. The elevation of these water sources ranges from 1,450 to 1,700 meters. Black toads are located in shallower waters where they can fully mature while they are young. The majority of black toad habitats in Anaxyrus are aquatic. Never have these toads been discovered farther than 12 meters from the water.
Appearance
The majority of black toads are black, however they can be distinguished by the light stripes and dots that dot their bodies. There are morphological differences between males and females. While females are significantly larger and have more spots, men have necks that are lighter in colour.
It takes 4-5 days for the eggs hatching once they are laid. They spend 3 to 5 weeks as tadpoles. Tadpoles can grow as long as 35 mm.
Diet
Black toads primarily consume insects for food. These insectivores consume smaller insects like ants and beetles. To avoid the heat of the day, they typically hunt in the early morning and late evening. The size of their prey is the primary distinction between the feeding habits of adults and growing children. Tadpoles consume minerals and organic matter that are suspended in the water. In contrast to fully developed toads, which eat larger insects like beetles and Lepidoptera larvae, younger toads consume ants, wasps, and mites. The most often found insect species in the stomachs of adult and young black toads were Diptera, Coleoptera, and Hymenoptera species. The majority of mollusks and mites were detected in young animals.
Reproduction
Ponds and marshy areas are good places for breeding. Black toads have many sexes. Males externally fertilize eggs from the female. After being finished, the eggs left submerged in vegetation.
In the spring, between March and April, black toads mate. Iteroparous and oviparous females produce numerous clutches of eggs over many seasons. Although they can lay their eggs in the spring, they can ovulate in November. Eggs are connected together after external fertilization and frequently fall next to one another in shallow vegetated areas. After mating, adults leave their eggs; kids are entirely autonomous from the moment they hatch. The age of sexual maturity has not been established.
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