A mountain-dwelling amphibian (3), the Cascades frog (Rana cascadae) is a medium-sized, slender species (2) (4) (5) which is named after the Cascades Mountain range in the western United States where it was first found (4).
The Cascades frog is generally mottled tan, brown, olive-green or olive-brown, with well-defined, inky black spots on the back. It is yellowish on the underside and on the back of the legs, with black, cream and greenish-yellow mottling on the groin, and cream along the side of the body (3) (4). Some individuals may also have a small amount of red pigmentation on the underside of the body (3). The Cascades frog also has a dark face mask, with a lighter stripe across the upper jaw which extends back towards the shoulder (2) (4) (5).
This species has two distinct parallel ridges of skin, called ‘dorsolateral folds’, which run along the back of the body, long legs, and only a small amount of webbing between the toes (3) (4). Male Cascade frogs may also have swollen grey pads, called nuptial pads, on the thumbs (3).
The tadpoles of the Cascades frog have an oval body and a pointed tail. They are dark brown to black, developing a metallic silvery or brassy pigmentation as they grow. The juvenile Cascades frog resembles the adult but lacks the yellow colouration on the underside of the body (3).
The Cascades frog produces a faint series of low, grating, clucking noises, and weak, slow, low croaks or chuckles (3) (4).
- Male length: up to 6.7 cm (2)
- Female length: up to 8.1 cm (2)
- Male weight: up to 28 g (2)
- Female weight: up to 56 g (2)