Amphibians
Columbia Spotted Frog
Rana luteiventris · also called Columbia spotted frog
The Columbia spotted frog is the spotted frog that got away. When the old spotted frog was split in two, its western sibling, the Oregon spotted frog, went into steep decline, while this one — more willing to travel overland, less fussy about which pond — carried on across a huge stretch of Alaska, Canada, and the interior Northwest. Only its stranded desert populations, clinging to isolated spring systems, are in real trouble.
Overview
The Columbia spotted frog, Rana luteiventris, is a medium-sized brown frog with ragged black spots and a salmon-red wash under the hind legs and belly, and eyes angled slightly upward. It lives in and beside permanent water — marshes, beaver ponds, lake edges, spring pools — from the lowlands to alpine lakes above 3,000 m, eating insects, spiders, worms, and slugs.
The more adaptable sibling
Split from the Oregon spotted frog in the 1990s, the Columbia species spends more time on land, moves between wetlands, and uses a wider range of water bodies, which is why it has held on where its strictly aquatic cousin has not.
Winter at the springs
Through the long cold winter the frog hibernates underwater, favouring undercut banks and spring heads where flowing groundwater stays unfrozen and oxygenated, sometimes gathering there in numbers. It emerges and breeds very early, at the edge of melting ice.
Status
Least Concern across its main range — one of the few western frogs not in broad decline. The Great Basin population of Nevada, Utah, and southern Idaho is isolated among desert springs, genetically distinct, and repeatedly petitioned for federal protection, threatened by groundwater pumping, drought, grazing, and introduced trout and bullfrogs.
Columbia Spotted Frog: common questions
What is the difference between the Columbia and Oregon spotted frogs?
They were considered one species until genetic and morphological work in the 1990s separated them, and they are now treated as sister species with almost no range overlap. The Oregon spotted frog lives west of the Cascade crest from British Columbia to Oregon, is highly aquatic, rarely leaves the water, needs shallow warm marshy breeding pools, and has declined severely, so it is federally threatened in the United States and endangered in Canada. The Columbia spotted frog lives east and north of that line across a vast interior range, is more terrestrial and more flexible about habitat, and remains common over most of its distribution. In the hand they are very similar, both brown with black spots and a reddish belly wash, and the reliable separation is range plus subtle differences in body proportions and coloration.
Where do Columbia spotted frogs go in winter?
They hibernate in water. As temperatures drop in autumn the frogs move to permanent water bodies and settle on the bottom of ponds and lakes or, very commonly, into undercut banks and the outflows of springs. Spring heads are favoured because groundwater emerges at a steady few degrees above freezing and keeps flowing, so the water there does not freeze solid and stays oxygenated enough for a frog to survive several months barely moving, absorbing oxygen through its skin. Frogs sometimes congregate at a good overwintering spring in numbers, which makes those sites important to protect. They emerge and breed very early, often at the edge of melting ice.
Is the Columbia spotted frog endangered?
Not as a whole. Across its main range in Alaska, Canada, and the northwestern states it is common and listed as Least Concern, and it is one of the few western North American frogs that has not suffered a broad collapse. The exception is the group of isolated populations in the Great Basin, in Nevada, Utah, and southeastern Idaho, which are separated from the main range by desert and confined to individual spring systems and headwater streams. Those frogs are genetically distinct and face groundwater extraction, spring diversion, drought, grazing damage, and introduced fish, and they have been the subject of repeated petitions for federal listing and of specific conservation agreements, though the species overall has not been listed.
How can you identify a Columbia spotted frog?
Look for a medium-sized frog, about 5 to 10 cm, with a brown or olive back that feels slightly rough, marked with irregular black spots that usually have lighter centres and indistinct edges. The most useful field marks are the belly and the eyes. The underside of the hind legs and the lower belly show a wash of orange, yellow, or salmon-red that becomes stronger in older frogs. The eyes are positioned high on the head and angled somewhat upward, giving the frog a distinctive expression. It has fairly short hind legs for a Rana and prominent dorsolateral folds down the back. Range is important too, as within its area the main confusion species are the northern leopard frog, which has neat pale-ringed spots, and various true frogs that lack the reddish belly.