Mountain Yellow-legged Frog

North America


Rana muscosa


  • Mortality through the fungal disease chytridiomycosis
  • Introduced aggressive fish species
  • Pesticide drift

The Mountain Yellow-Legged Frog lives in California, within the water ecosystems of the San Bernardino Mountains, the San Gabriel Mountains, and the San Jacinto Mountain though some population can also be found in the southern part of the Sierra Nevada. Its multi-colored skin which resembles moss inspired its scientific name, Rana Muscos (Latin for full of moss).

The infectious chytrid fungus which decimated many amphibian populations around the world is considered as one of the reasons for the decline of the Mountain Yellow-Legged Frog. It attacks the keratinized parts, which cause severe stress, damage, and fatal death to frogs.

The presence of trout in its natural habitat means competition for limited food resources and its tadpoles being vulnerable to being eaten. Frogs also are rather defenseless against attacks of birds and garter snakes in the area. Livestock animals which graze near and around the bodies of water also can trample the frogs to death or cause significant damage and pollution to the water.

As more lands are used for agricultural purposes, it means an unending risk of being exposed to pesticides and other chemicals which are also fatal for the frogs.