Columbia spotted frog
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|Columbia spotted frog
Rana pretiosa luteiventris Thompson, 1913
The Columbia spotted frog (Rana luteiventris) is a North American species of frog. It is green to brown in color with spots on the dorsal surface. The belly and upper lip are white in color. Individuals can be distinguished from other Rana species by their shorter back legs, narrow snout, and upturned eyes. Since they spend most of their time in the water, they also have more webbing in their hind feet than similar species. Although not threatened, this animal has been studied as a model species for the effects of habitat fragmentation.
The Columbia spotted frog is a medium-sized frog reaching lengths of up to 3.5 in (90 mm). Its color ranges from a dark, olive green to light brown with irregularly shaped black spots on its back and legs (rendering its name). Its skin texture, like the rest of the genus, varies from a rough to a smooth texture, with small folds of skin along the back. This frog exhibits a unique feature regarding its color. A light-colored strip runs along the upper lip, and the ventral sides of the frog are usually colored either pink or yellow, but only in the adult form.
This frog is well known by a few of its physical characteristics, as well. It has a long, narrow snout and upturned eyes. The spotted frog is known as a very aquatic amphibian; the webbing on its feet extends all the way to the end of its longest toe. When comparing this frog to others of the same size, such as the northern leopard frog, it tends to have shorter hind legs.
The tadpoles are brownish-green in color, which runs dorsally along the tadpole. Gold spots are also intermittent throughout this coloring. The tadpoles have upturned, inset eyes. They usually reach around 3.1 inches (80 mm) in length before maturing to adults.
The Columbia spotted frog, like most other frogs, is fairly aquatic. Their habitats are found generally near permanent bodies of water, which can include lakes, ponds, slow-moving streams, and marshes. These frogs were found to need specific habitat characteristics within these broader habitat characteristics. Adult spotted frogs inhabit mostly seasonally flooded sites, where the water source is constant, but at certain times of the year, increases exponentially in both the amount and level of water available.
These frogs are a constant victim to predation, so they need to be in an area with an abundant source of low-growing vegetation. A large part of this vegetation is usually submerged, including many forms of algae and other aquatic plants. The spotted frog does not usually inhabit areas with large amounts of grasses and sagebrush growing. These plants are not as aquatic as the algae, which makes them a poor hiding place for the spotted frog. The Columbia spotted frog rarely ventures outside of these areas, but for breeding, they have been known to travel outside of these areas.
The Columbia spotted frog reproduces similarly to other amphibians, but with a few unique details added. They need to reproduce in areas where emergent vegetation is present. Two of the favorite types of vegetation for reproduction are reed canary grasses and cattails. The spotted frog reproduces in the same areas where it lives- ponds, slow-moving streams, and lakes.
The males present to the females a chorus (type of song) to try to attract a female for mating. This song ranges from a series of clicks to long, glottal sounds. This frog has an unusual characteristic of its reproduction. The male frog arrives at the breeding grounds before the female and establishes the oviposition site before the females become reproductively active.
Once the oviposition site is created, the female then begins to lay her eggs in shallow water, and the male fertilizes the eggs. The egg masses, fairly large in size, range up to 1300 eggs. The egg masses, once laid, absorb water and become the size of a softball. These eggs are not attached to any type of vegetation, but are left free-floating in a permanent water source. Soon after, the eggs hatch into tadpoles.
The Columbia spotted frog's breeding schedule depends heavily on geographical location and elevation. In British Columbia, the frog will breed during February at sea level. In areas around Utah, the frog will breed around mid-March at an elevation of about 1,395 m (4,577 ft). At areas of Wyoming, the frog will reproduce from May through June at elevations around 2,377 m (7,799 ft). The female will breed yearly at lower elevations and about every two to three years at higher elevations.
This frog is opportunistic at best. It will eat a variety of insects, including grasshoppers, ants, wasps, beetles, and moths. These insects comprise more than 50% of the frog's diet. This frog will also eat seemingly unusual animals, such as crustaceans, mollusks, arthropods, and arachnids.
In addition to being an insectivore, the Columbia spotted frog will eat algae, organic debris, a variety of plants, and other smaller, water-dwelling organisms.
- Cossel Jr., John (1997): Rana luteiventris, Idaho Museum of Natural History. Accessed March 10, 2006
- Hammerson, Geoffrey (2004). "Rana luteiventris". IUCN Red List of Threatened Species. Version 3.1. International Union for Conservation of Nature. Retrieved 12 May 2006.
- Hillis, D. M. & T. P. Wilcox (2005): "Phylogeny of the New World true frogs (Rana)." Molecular Phylogenetics and Evolution 34 (2): 299–314. doi:10.1016/j.ympev.2004.10.007 PMID 15619443 PDF fulltext.
- Hillis, D. M. (2007): "Constraints in naming parts of the Tree of Life." Molecular Phylogenetics and Evolution 42 (2): 331–338. doi:10.1016/j.ympev.2006.08.001 PMID 16997582.
- Munger, James, et al. (2008): "U.S. National Wetland Inventory Classifications as Predictors of the Occurrence of Columbia Spotted Frogs (Rana luteiventris) and Pacific Treefrogs (Hylaregilla)." Conservation Biology 12 (2): 320–330. JSTOR 2387502 doi:10.1111/j.1523-1739.1998.97012.x.
- Davis, Abbey and Paul Verrell (2005): "Demography and Reproductive Ecology of the Columbia Spotted Frog (Rana luteiventris) across the Palouse." Canadian Journal of Zoology 83 (5): 702–711. doi:10.1139/z05-061.
- Reaser, Jamie K. (2000): "Demographic Analysis of the Columbia Spotted Frog (Rana luteiventris): Case Study in Spatiotemporal Variation." Canadian Journal of Zoology 78 (7): 1158–1167. doi:10.1139/z00-043.
- Cossel, John, Groves, Charles Peterson, Ean Harker, Stephen Burton, Mike Legler, "Rana luteiventris." 2000. 21 Apr 2009.
|Wikimedia Commons has media related to Rana luteiventris.|
|Wikispecies has information related to: Rana luteiventris|
- Rana luteiventris at CalPhotos
- Rana luteiventris - Columbia Spotted Frog Information Page
- Oregon Department of Fish and Wildlife Information and Conservation
- Wyoming Game and Fish Information and Conservation
- Utah Division of Wildlife Resources Information and Conservation
- Fish and Wildlife Branch- British Columbia Information and Conservation
- Population Estimates for the Toiyabe Population of the Columbia Spotted Frog (Rana luteiventris), 2004-10 United States Geological Survey
- Columbia Spotted Frog recordings