Western toad

Taxobox | name = Western toad
status = NT | status_system = IUCN3.1
trend = down


image_width = 240px
regnum = Animalia
phylum = Chordata
classis = Amphibia
ordo = Anura
familia = Bufonidae
genus = "Bufo"
species = "B. boreas"
binomial = "Bufo boreas"
binomial_authority = Baird & Girard, 1852
synonyms = "Anaxyrus boreas"
"Bufo politus"

The Western toad or boreal toad ("Bufo boreas") is a large toad species, between 5.6 and 13 cm long, of western North America. It has a white or cream dorsal stripe, and is dusky gray or greenish dorsally with skin glands concentrated within the dark blotches. Its parotoid glands are oval, widely separated, and larger than the upper eyelids. It is mottled venter, has horizontal pupils, and lacks cranial crests.

Compared to females, males have smoother skin, reduced dorsal blotching, and nuptial pads (thickened skin) on their forefeet during breeding season. In juveniles of this species, the dorsal stripe is weak or absent. Large young have prominent dorsal and ventral spotting and yellow feet.

Breeding occurs between March and July in mountainous areas, and as early as January in lower-elevation regions. The female lays up to 17,000 eggs stuck together in strings that adhere to vegetation and other objects along water edges. [Grismer, L. L. (2002). "Amphibians and Reptiles of Baja California". Los Angeles: University of California Press, 66.]

The Western toad is a common species occupying a wide variety of habitats, but is listed as near threatened largely due to the impact of disease, especially chytridiomycosis. [IUCN2006|assessors=Hammerson "et al"|year=2004|id=3179|title=Bufo boreas|downloaded=11 May 2006 Database entry includes a range map and justification for why this species is near threatened] It is frequently encountered during the wet season on roads or near water at other times. When handled adults often vocalize, making a sound like a peeping chick while struggling. It eats any type of insect it can catch. It also has a very long jump.

References

* (2004) The history of a Nearctic colonization: Molecular phylogenetics and biogeography of the Nearctic toads ("Bufo"). "Evolution" "58": 2517–2535.
* This article is based on a description from "A Field Guide to the Reptiles and Amphibians of Coastal Southern California", Robert N. Fisher and Ted J. Case, USGS, http://www.werc.usgs.gov/fieldguide/index.htm.