Columbia Spotted Frog

Rana luteiventris (Rana pretiosa)

Columbia Spotted Frog

Distribution in Wyoming

 

 

 

 

 

 

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The distribution of the Columbia Spotted Frog lies in large contiguous regions and disjunct pockets, reaching from the Yukon into British Columbia and south along the Rocky Mountains into northern Utah and Nevada. In Wyoming these frogs are found in the northwestern foothills and montane life zones, from the Absaroka Mountains south into the Wyoming Range and Wind River Range. A second smaller and isolated population exists in the Big Horn Mountains. They remain close to the clear, permanent waters of lakes and beaver ponds or the riparian habitat of sloughs and backwaters along cold, slow flowing streams. The margins of these areas are usually heavily vegetated with sedges, rushes, and grasses. They are occasionally found moving between winter hibernacula, breeding sites, and foraging areas within the wet interior of the coniferous forest.

Columbia Spotted Frog Columbia Spotted Frog

They are medium sized frogs with average lengths (SVL) in the range of 2-3 inches. These frogs do have a dorsolateral fold, running along the sides from behind the eye to the waist, but the coloration of the fold is seldom distinct and can fade with age. The dorsal surface is heavily blemished and is typically a uniform dull brown or tan, often with a green pallor. The pimpled skin has many eruptions scattered about (often with lighter centers), but these lack any discernable pattern and appear more like a serious rash than glandular warts. Their facial features include a black mask between the eye and the snout and a white smear running along the upper jaw and ending on the shoulder. (Some note the eyes as being up-turned rather than out-turned.) The hind legs—long for a toad, short for a frog—are ample for a leisurely leap or an occasional swim. Look to the ventral surface of these frogs for their specialty: a light touch of salmon pigmentation on the lower abdomen which becomes more heavily garnished as it puddles down the legs and on to the webbing of the feet.

Columbia Spotted Frog Columbia Spotted Frog

Breeding activities begin in late May or early June and snow or ice may still remain in the area. They prefer the earliest sites available in the warming shallows of northern shores. Males have a small voice and advertise their availability by delivering a series of faint croaks, clucks, and clicks. They use enlarged thumbs (nuptial pads) to clasp females and the resulting amplexus may last more than a day. Each black and white egg is encased within a pair of membranes and the spawn of 250 to 750 eggs adhere to each other and form a large floating mass. Numerous masses from different mating pairs can be found in communal breeding sites. Depending on water temperature, hatching can take from 5-20 days with metamorphosis requiring another 8-16 weeks. Many breeding sites fail to produce young of the year because tadpoles fail to transform before the ponds dry up or before the onset of colder temperatures. Sexual maturity is reached in 2-4 years.

Columbia Spotted Frog Columbia Spotted Frog