Boreal toad

The boreal toad (Anaxyrus boreas boreas) is a subspecies of the western toad (Anaxyrus boreas). They are commonly found in the Southern Rocky Mountains and in recent, their population has been on the decline due to an emerging amphibian disease, chytrid fungus.[1] The boreal toad is currently listed as an endangered species by Colorado and New Mexico. It is known in Colorado as the only alpine species of toad.

Anaxyrus boreas boreas
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Anura
Family:	Bufonidae
Genus:	Anaxyrus
Species:	A. boreas
Subspecies:	A. b. boreas
Trinomial name
Anaxyrus boreas boreas (Baird and Girard, 1852)

Appearance

Boreal toads lack a cranial crest and can be distinguished from the Western toad by looking at its underbelly, which is covered by a considerable amount of dark blotches.[2] Adult males on average are between 2.4–3.1 inches and females are 2.9–3.9 inches[3] Their coloration can range from brown to green and they have a distinct white middorsal stripe. Both sexes have dry, warty skin and oval parotoid glands. Male boreal toads have no vocal sac, and therefore have no mating call.

Habitat and distribution

The boreal toad is currently found in Wyoming, Colorado, Idaho, Washington, British Columbia, Alaska, Utah and northern New Mexico. It prefers high-altitude wet habitats (8,000–12,000 ft in elevation) such as lakes, marshes, ponds, bogs and quiet shallow water[4] Habitat selection for western toads is important because they require open water for breeding, and they can die if they are too exposed to seawater.[5]

Diet

Boreal toads feed on a wide variety of insects and invertebrates. Their diet includes grasshoppers, beetles, flies, and mosquitos.

Reproduction

The breeding season is usually from May to Late July and occurs in marshes and still waters. Females on average lay about 3,000 to 8,000 eggs. The tadpoles take around two months to develop and are usually black in color.[6]

Threats

The chytrid fungus (Batrachochytrium dendrobatidis) causes a skin disease in many species of amphibian. Little is known to how it spreads, but it affects amphibians' by feeding off of the keratin produced by the amphibian, which causes keratosis. Keratosis then can either suffocate the amphibian, or cause it to go into cardiac arrest. This can be detrimental to amphibians because it inhibits their ability to absorb water and electrolytes.[7]

References

1. "Boreal Toad." U.S. Fish and Wildlife Service Home. 29 June 2011. Web. 12 Dec. 2011
2. "Boreal Toad." Archived 2011-07-27 at the Wayback Machine Center for Native Ecosystems. Web. 11 Dec. 2011.
3. Pierce, Leland J. S. Boreal Toad (Bufo Boreas Boreas) Recovery Plan. [Santa Fe, N.M.]: New Mexico Dept. of Game & Fish, 2006.
4. "Boreal Toad." Archived May 12, 2012, at the Wayback Machine Colorado Division of Wildlife. 21 May 2010. Web. 12 Dec. 2011.
5. Paul E. Bartelt, Robert W. Klaver, Warren P. Porter, Modeling amphibian energetics, habitat suitability, and movements of western toads, Anaxyrus (=Bufo) Ecological Modelling, Volume 221, Issue 22, 2010, Pages 2675-2686, ISSN 0304-3800
6. "Yellowstone National Park – Boreal Toad (U.S. National Park Service)." U.S. National Park Service – Experience Your America. 10 June 2009. Web. 12 Dec. 2011.
7. "Chytrid Fungus." Archived 2011-12-17 at the Wayback Machine savethefrogs.com 2011. Web. 12 Dec. 2011.

Further reading

Carey, Cynthia, Judsen E. Bruzgul, Lauren J. Livo, Margie L. Walling, Kristin A. Kuehl, Brenner F. Dixon, Allan P. Pessier, Ross A. Alford, and Kevin B. Rogers. "Experimental Exposures of Boreal Toads (Bufo Boreas) to a Pathogenic Chytrid Fungus (Batrachochytrium Dendrobatidis)." EcoHealth 3.1 (2006): 5–21.