Cascades Frog

AT A GLANCE
Common Name: Cascades Frog
Scientific Name: Rana cascadae
Category: Amphibians
Subcategory: True Frogs
Size: Snout-vent length 5.0 to 7.5 cm (2.0 to 3.0 in); females larger than males
Weight: 15 to 30 g (0.5 to 1.1 oz)
Lifespan: 5 to 8 years in the wild
Diet: Insectivorous / Generalist (mayflies, caddisflies, beetles, water striders, grasshoppers, and spiders)
Habitat: High subalpine lakes, montane stream pools, and glacial meadows
Range: Cascade Mountains of Washington, Oregon, and California
Conservation Status: Near Threatened (IUCN Red List)

Overview

The Cascades Frog (Rana cascadae) is a handsome, high-altitude ranid frog endemic to the alpine meadows and glacier-fed tarns of the Pacific Northwest’s Cascade Mountains. Characterized by its golden-brown dorsal skin marked with crisp, inky-black spots and a warm honey-yellow or apricot belly, this mountain amphibian thrives in sun-drenched subalpine wetlands, surviving long winters buried in the mud of frozen mountain ponds.

Biology and Physical Characteristics

Rana cascadae has a slender, streamlined build with long, muscular jumping legs and fully webbed hind feet. Its dorsal coloration ranges from olive-green to rich copper-brown, adorned with sharply defined, ink-blot black spots with light halos. A dark facial mask extends from the snout through the bronze eye and tympanum, while its underbelly and inner thighs are tinted a radiant, translucent honey-yellow.

Behavior and Ecology

A sun-loving subalpine resident, the Cascades Frog spends warm summer days basking along the grassy margins of shallow snowmelt pools and subalpine stream channels, leaping with colossal bounds into deep water when startled. As early autumn snows blanket the peaks, frogs dive to the deepest mud bottoms of permanent spring-fed tarns that do not freeze solid, hibernating for up to nine months beneath deep ice.

Conservation and Human Impact

Classified as Near Threatened by the IUCN, the Cascades Frog has suffered substantial historical range contractions, especially in the southern Cascades of northern California. Major threats include the historical stocking of non-native predatory trout into naturally fishless alpine lakes, airborne pesticide drift, and fungal chytridiomycosis.

Interesting Factoid

The Cascades Frog can spend up to nine months of every year completely dormant beneath six feet of ice and snow, breathing through its skin in the mud of subalpine glacial ponds.