Cascades Frog

ESA status: under review (July 2015)

The Cascades frog (Rana cascadae) is named for its home region. Rana is Latin for frog and cascadae refers to the Cascade Mountains. However, this species also occurs in the Olympic Mountains of northwest Washington and Trinity Mountains of northern California.



About the size of a small child’s hand (4–7.6 cm long), these montane (mountain dwelling) amphibians are usually found above 730 m (2,400 ft) elevation in wet meadows, damp forest bogs, lakes, ponds, and small streams. They rely on clean and permanent water sources for survival.

Cascades frogs are most active from May to October. In winter, they burrow into muddy bottoms of lakes or ponds to hibernate. Once the snow melts, males begin calling during the day, but mostly at night. They call both above and below the water surface to find mates and announce their territory to other males.



Adult frogs are generalist predators that eat a variety of invertebrates such as water striders, caddisflies, mayflies, crane flies, ants, grasshoppers, and spiders. They hunt and forage at the water surface, in wet meadows, and other aquatic habitats. Tadpoles feed at the bottom of waterbodies on detritus and microorganisms such as algae and fungi.



Like other frogs (and amphibians) they are poikilothermic ectotherms meaning their body temperature fluctuates with and is the same as the environmental temperature. They move around among habitats to optimize their body temperature.

Cascades frogs breed from March to August in still or slow-moving water. The bicolored (black on top and white on bottom) eggs are laid in shallow areas near shorelines of shallow ponds, lakes, and slow-moving streams. The softball-sized mass of 300–500 eggs can be free floating, but is often attached to vegetation.



Frogs undergo complete metamorphosis (transformation). Tadpoles emerge from the eggs and are entirely aquatic—they have gills, a tail fin, and no legs. Rana cascadae tadpoles are dark brown with copper speckling. They grow up to 5 cm long. They transform into adults by August or September, growing legs, reabsorbing their tail, and developing lungs. Frogs become sexually mature and start breeding 2–3 years after metamorphosis. Their typical lifespan is 5–7 years.

Populations have declined in areas where they were once abundant. At the southern extent of their range, near Lassen Volcanic National Park, only a few known populations remain. Sadly, they appear to be extirpated in Lassen Volcanic National Park.



Factors contributing to population decline are the introduction of nonnative trout for recreational fishing, habitat alteration or loss, fire suppression, pesticides, climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change , and drought and diseases. The spread of chytrid disease caused by the fungus, Batrachochytrium dendrobatidis, has led to large scale loss in amphibian populations.



Rana cascadae is one of 53 candidate species currently under review for listing under the federal Endangered Species Act and it is recognized as a species of concern in California, Oregon, and Washington. Conservation and habitat restoration efforts include protecting breeding and over-wintering sites, deepening and expanding breeding pools, and preventing the spread of chytrid disease and other pathogens