The Cascades frog (''Rana cascadae'') is a species of

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

in the family Ranidae found in the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

, mainly in the

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

and

Olympic Mountains The Olympic Mountains are a mountain range on the Olympic Peninsula of the Pacific Northwest of the United States. The mountains, part of the Pacific Coast Ranges, are not especially high – Mount Olympus is the highest at ; however, the easter ...

Description

Appearance

The Cascades frog has a green to brown color on its back and a light yellow on its throat and belly. A range from a few to about 50 gray spots are located on its back. Depending on the situation, the spots may change color from the lighter gray/brown to a darker black spot. The colors on the frog's back are also used to attract mates. The shape of the frog's head is most commonly an oval with the mouth coming out to a slight specific point. Adult frogs range from 50 to 65 mm in length.

Voice

The advertisement call of the ''R. cascadae'' is a faint series of low, grating, clucking noises. Calls are produced at night and during the day from above and under the water.

Habitat

The Cascade frog was first discovered in the

Cascade Mountains The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...

in the California regions. It can be found throughout the Cascade Mountains from

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

through

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, and

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. They concentrate heavily around the volcanic area of the peaks. Its natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s are temperate

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

s, temperate

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s, freshwater

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s, intermittent freshwater lakes, freshwater

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es generally between in elevation. The range may extend lower in Washington. They can be found in relatively small, permanent and temporary ponds also found along streams in summer. The adults generally stay close to water, particularly along sunny shores, under dry summer conditions, but can be found traversing uplands during high humidity.

Behavior

Reproduction

Cascades frogs lay their eggs May 20 through July 10, depending on when the snow melts and creates ponds in which the eggs are laid. First, egg masses are deposited in comparatively warm water along gradually sloping shorelines, often over soft substrates protected from severe wave action. Females can only breed once a year, but whether they skip years remains unknown. A single female will lay up to 425 eggs at a time, but very few tadpoles will live past their first year. The placement of clusters of egg masses in shallow water soon after the first thaw can make them susceptible to freezing and pathogen transmission between clusters. The eggs hatch within eight to 20 days. Their larval period lasts 80 to 95 days. Most frogs reach their full size after three years, after which they become fertile and can begin mating. Adults appear to use the same breeding sites for several years. Rana cascadae 6206

Diet

Larvae are thought to be primarily

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

feeders, but specific preferences are not well known. The diets of the adult Cascades frogs are poorly known, as well, but they are thought to consume a variety of invertebrate prey and will occasionally consume other frogs and tadpoles.

Population

Females have a higher mortality rate than the males, but both are believed to live over five years, sometime reaching up to seven. Recently, a decline in the Cascade frog species has occurred, but the declines are not too serious, and usually only occur in the southern part of this frog's range. Causes are not fully known, but introduced predators such as trout and

bullfrog ''Bullfrog'' is a common English language term to refer to large, aggressive frogs, regardless of species. Examples of bullfrogs include: Frog species America *Helmeted water toad (''Calyptocephalella gayi''), endemic to Chile *American bullfro ...

s, UV-B radiation, diseases, and loss of open meadow habitat due to fire suppression have been suggested. Fertilizers such as urea may also pose a threat to the Cascades frogs, because the juveniles were not capable of sensing and avoiding toxic levels in laboratory studies.

Predation

The main predators of the Cascades frogs are the

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

, mink, coyote,

water bug Waterbug or water bug can refer to any of several things: True bugs * The true water bugs (Nepomorpha), including such insects as giant water bugs, creeping water bugs and backswimmers * Various other aquatic true bugs, known collectively as wate ...

s (Belostomatidae),

garter snake Garter snake is a common name for generally harmless, small to medium-sized snakes belonging to the genus ''Thamnophis'' in the family Colubridae. Native to North and Central America, species in the genus ''Thamnophis'' can be found from the sub ...

s (''Thamnophis sirtalis''), and several bird species, such as the

sharp shinned hawk The sharp-shinned hawk (''Accipiter striatus'') is a small hawk, with males being the smallest hawks in the United States and Canada, but with the species averaging larger than some Neotropical species, such as the tiny hawk. The taxonomy is fa ...

owls Owls are birds from the Order (biology), order Strigiformes (), which includes over 200 species of mostly Solitary animal, solitary and Nocturnal animal, nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vi ...

Canada jay The Canada jay (''Perisoreus canadensis''), also known as the gray jay, grey jay, camp robber, or whisky jack, is a passerine bird of the family Corvidae. It is found in boreal forests of North America north to the tree line, and in the Rock ...

s, and

American robin The American robin (''Turdus migratorius'') is a migratory bird of the true thrush genus and Turdidae, the wider thrush family. It is named after the European robin because of its reddish-orange breast, though the two species are not closel ...

. The long-toed salamander and adult ''R. cascadae'' frogs are predators to the eggs and tadpoles, as well.

Pharmacology

To guard itself from other

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

s that live in the environment, the Cascades frog produces high concentrations of antimicrobial

peptides Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A p ...

it secretes from its skin in response to infection or stress. According to Conlon, "frogs belonging to the genus ''Rana'' represent a particularly rich source of peptides with diverse structures and specificities against micro-organisms". He began testing the frog secretions to determine whether or not the peptides would have an effect on bacteria that attack human cells. He found the chemical ranatuerin-2CSa, which is produced by ''R. cascadae'', impeded the growth of ''E. coli'' and ''S. aureus'' in humans. These anti-infective agents give the Cascades frogs “therapeutic potential for the future”, according to Conlon. A drawback of the ''R. cascadae'' peptide, however, is it acts as a blood thinner for humans and decreases the supply of oxygen in the bloodstream. A recently discovered chemical, D-lysine, was produced by adding amino acids to the peptides to help decrease the toxicity to the human cells. It is a substitute for ranatuerin-2CSa, which makes analogs of naturally occurring peptides that lack significant

hemolytic Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

activity. Since the strength of the blood thinning properties is greatly reduced, it is almost harmless to humans.

References

*Blaustein, A. R., T. S. Garcia, D. J. Paoletti. Correlated trait response: comparing amphibian defense strategies across a stress gradient. Canadian Journal of Zoology Vol. 87 Issue 1. (Jan 2009):41-49. *Briggs, Jeffrey L. and Robert M. Storm. “Growth and Population Structure of the Cascade Frog, Rana cascadae Slater” Herpetologica, Vol. 26, No. 3 (Sep. 1970): 283-300 *Case, Susan M. “Biochemical Systematics of Members of the Genus Rana Native to Western North America” Systematic Zoology, Vol. 27, No. 3 (Sep., 1978): 299-311 *Conlon, J. Michael, Anusha P. Subasinghage, Chandralal M. Hewage. “Conformational analysis of the broad-spectrum antibacterial peptide, ranatuerin-2CSa: Identification of a full length helix–turn–helix motif”. Proteins & Proteomics. Vol. 1784 Issue 6 (June 2008):924-929 *Conlon, J. Michael, et al. “Peptide defenses of the Cascades frog Rana cascadae: implications for the evolutionary history of frogs of the Amerana species group”. Peptides Vol. 28 Issue 6. (June 2007):1268-1274 *Davidson, Carlos. Booklet to the CD Frog and Toad Calls of the Pacific Coast - Vanishing Voices. Cornell Laboratory of Ornithology, 1995. * (2005): Phylogeny of the New World true frogs (''Rana''). '' Mol. Phylogenet. Evol.'' 34(2): 299–314. PDF fulltext
* (2007) Constraints in naming parts of the Tree of Life. '' Mol. Phylogenet. Evol.'' 42: 331–338. *Kleiner, Kurt. “Multiple killers”. New Scientist. Vol. 165 Issue 2227 (2006): 16 *Rollins- Smith, Louise, et al. “Antimicrobial Peptide Defenses in Amphibian Skin.” Integrative and Comparative Biology. 45 (2005):137–142 *Slater, James R. “Description and Life-History of a New Rana from Washington. Herpetologica.Vol. 1, No. 6 (Mar. 30, 1939): 145-147+149

External links

Western Soundscape Archive - Cascades Frog recordings
{{Taxonbar, from=Q59316 Rana (genus) Amphibians described in 1939 Amphibians of the United States Amphibians of North America Taxonomy articles created by Polbot