Western Toad

Western toad (Anaxyrus boreas)

Taxonomy

Western Toad Taxonomy

	Kingdom	Phylum	Class	Order	Family	Genus
Classification	Animalia	Chordata	Amphibia	Anura	Bufonidae	Anaxyrus

Description

The Western Toad is a species of amphibians ranging in 2 to 5 inches in length with dusky gray or greenish dorsals, and skin glands concentrated inside the dark blotches. Western Toads also have a very distinguishable white or cream dorsal stripe. It has round, widely divided parotid glands that are larger than the upper eyelids and it lacks cranial crests but has a speckled ventro and horizontal pupils. Male western toads are unique for the fact that they develop smoother skin during breeding seasons. They also have less dorsal blotching, and nuptial pads (thickened skin) on their forefeet in comparison to females. Males are also smaller than female Western Toads. The dorsal stripe of this species' juveniles is missing or very faint. Yellow foot and vivid dorsal and ventral markings are features of large young.

Western Toad tadpoles are dark in appearance with light spotting on the body creating a gold shimmer when viewed in bright lights. Their underside is slightly paler than their overall body. The juveniles' eyes are dorsally situated on the top of their head ending in a tail which is dark in color with fins darker than the rest of of the tail itself.

Range and Subspecies

Western toads are known to inhabit a fairly wide territorial range, spanning across western British Columbia, northern Baja California, southern Alaska, Oregon, Idaho and Washington, central and western Wyoming, western Colorado, and the higher plateaus and mountains of Utah. This species occurs in a variety of terrestrial habitats including prairies, forests, canyon grasslands and ponderosa pine-Oregon oak habitat. They appear absent from most of the shrubsteppe and steppe zones with the exception of the canyon grasslands in southeast Washington. Breeding waters are usually permanent and include wetlands, ponds, lakes, reservoir coves and the still-water off-channel habitats of rivers, as well as river edges.

There are two subspecies of the Western toad, namely Anaxyrus boreas boreas and Anaxyrus boreas halophilus

Image	Scientific name	Common Name	Description	Distribution
	Anaxyrus boreas boreas	Boreal toad	is characterized by an underbelly zone spotted with a decent amount of dark blotches, while the cranial crest is absent.	Boreal toads inhabit southern Alaska and western British Columbia, western Montana, Nevada, northern California, Oregon, Idaho, Washington, western Utah, and western Wyoming
	Anaxyrus boreas halophilus	California toad	differs from the Western toads by possessing larger eyes, a wider head, and considerably smaller feet. California toads are also known to have weaker developed dorsal stripe zone margins.	Found across the Central Valley of California through Coastal and Baja California, as well as in western Nevada

Life Cycle and Behavior

The Western Toad's lifecycle begins as eggs which are laid in long strings on bare sediments or intertwined in vegetation in shallow water near shore. Individual females produce approximately 12,000 eggs per clutch on average and tend to lay them around vegetation in still water. The egg strings are similar to Woodhouse’s toads but the latter has only one gel layer. breeding starts in mid-April at low elevation sites in western Washington and in late April or early May at low elevation sites in eastern Washington. Toads at higher elevations tend to breed later. Toads breed in the still waters of lakes and ponds, but they also breed within slower moving sections of rivers. Onset of egg laying at each location varies from one to three weeks each year depending on site conditions such as snow melt.

Tadpole development to metamorphosis takes approximately two months depending on temperature and food availability. The newly metamorphosed toads disperse from the breeding sites in groups for 1 to 2 weeks. Informal observations indicate that many populations return to the same breeding location each year. Transformed toads are primarily terrestrial, but often occur near water bodies, especially in drier climates.

Diet and Predators

Western toads eat a variety of invertebrates, mostly insects, but also worms. Tadpoles eat algae and detritus (organic material) in the aquatic environment. They are known to wait for their prey, either in shallow burrows created by other animals or straight on the surface of the ground. Instead of actively hunting for their prey, Western toads’ are foragers. The way prey items are ingested by Anaxyrus boreas is thanks to a quick tongue extension, known as a zot. The zot allows Western toads to snap up their prey.

Common predators include fish, birds, and snakes. To defend themselves, the Western Toad can secret a foul-tasting toxin from their parotoid glands, however, some ravens have learned to avoid the areas that contain this toxin.

References

“Western Toad.” NDOW, www.ndow.org/species/western-toad/. Accessed 27 Apr. 2023.

“Western Toad | Washington Department of Fish & Wildlife.” Wdfw.wa.gov, wdfw.wa.gov/species-habitats/species/anaxyrus-boreas#desc-range.

“Western Toad Care Sheet | Reptiles’ Cove.” Reptilescove.com, 4 May 2020, reptilescove.com/care/frogs/western-toad. Accessed 27 Apr. 2023.