The Latin name of the frog species is Rana muscosa. Their food consists of insects, eggs, tadpoles and even other frogs. Frogs are important for the ecological balance in an ecosystem. They keep the insect population down.

Rana muscosa is endemic to California, USA. The yellow-legged frog from Southern Mountain once stretched from Palomar Mountain in San Diego County through the San Jacinto, San Bernardino and San Gabriel Mountains in Riverside, San Bernardino and Los Angeles counties in Southern California.

The adult Mountain yellow-legged frog lives mainly on insects found on land and also the aquatic insects that seek out on the beach and live in shallower water. Tadpoles live on algae along rocky lake bottoms and other watercourses.

Highly Endangered

The Mountain yellow-legged frog is highly endangered and there are less than 200 individuals left in the wild. The goal is to try to multiply the frogs in captivity in order to then be able to reintroduce them into the wild.

Chytrid fungus

The Mountain yellow-legged frog are highly susceptible to a chytrid fungus commonly known as “Bd” that is sickening millions of frogs around the world. To treat frogs that have been exposed to Bd, biologists build large, 180*180 cm net pens to hold the frogs in the lake and catch as many frogs as possible. Treating a sufficient number of frogs in the population can prevent local extinction. Mountain yellow-legged frogs get to soak in an antifungal treatment solution for approximately 10 minutes once a day for eight days. The treatment reduces the amount of fungus on the frogs’ skin, giving their immune systems an opportunity to catch up and begin to fight the fungus naturally.

Mountain’s yellow-legged frog complex

This frog is one of the two species within the mountain’s yellow-legged frog complex. The two species are Rana muscosa and Rana sierrae. Both species need water to survive and go no further than a meter or two from the water’s edge.

Both Rana sierrae and Rana muscosa are yellowish in the skin. From above, they are reddish brown and have black or brown spots marked. The tips of the toes are dark. The entire underside of the frog is yellow or light orange. Another similar species is the Foothill Yellow legged frog, which is more transparent than the Mountain yellow-legged frog. The yellow colour extends towards the forelegs. Dorsolateral folds are usually present, but they can often be quite indistinct.

The Mountain yellow-legged frog tadpoles are black or dark brown. The tadpoles are large, usually over 10 cm long in total. It takes 1-4 years for the tadpoles to become a frog.

What distinguishes the two species Rana muscosa and Rana sierrae is that the Mountain yellow-legged frog (Rana muscosa) has longer legs. When the leg is folded towards the body, the tibiotarsal joint usually extends beyond the outer veins. Mating calls also separate the two species. Rana muscosa’s mating calls lack transitions between pulsed and noted sounds. Both species use their mating calls underwater. The males can also be heard above the water surface, but only if you are really close, no more than two meters away. The mitochondrial DNA also distinguishes the two species from each other. The mitochondrial DNA, male advertisement calls, and morphology datasets are geographically concordant.