Head to head
Sierra Nevada Yellow-Legged Frog vs Mountain Yellow-legged Frog
The Sierra Nevada yellow-legged frog and the mountain yellow-legged frog were treated as a single species until genetic and call studies in the 2000s revealed two distinct populations, each facing the same catastrophic combination of introduced trout and disease but confined to different mountains of California.
| Sierra Nevada Yellow-Legged Frog | Mountain Yellow-legged Frog | |
|---|---|---|
| Scientific name | Rana sierrae | Rana muscosa |
| Range | Northern and central Sierra Nevada | Southern California mountains (San Gabriel, San Bernardino, San Jacinto) |
| Population size today | Recovering in protected areas | Very small, critically reduced |
| Main historical threat | Stocked trout and chytrid fungus | Stocked trout and chytrid fungus |
| Recovery status | Documented rebound in Yosemite | Recovery far more limited |
| Taxonomic history | Split from Rana muscosa in the 2000s | Retains the original species name |
| Distinctive feature | Yellow leg wash, garlic smell | Yellow leg wash, garlic smell |
| Conservation status | Endangered | Endangered |
Sierra Nevada Yellow-Legged Frog vs Mountain Yellow-Legged Frog: common questions
Why were these two frogs once considered the same species?
The Sierra Nevada yellow-legged frog and the mountain yellow-legged frog were treated as a single species, Rana muscosa, until genetic and call studies in the 2000s showed that the northern and central Sierra Nevada populations were distinct from the southern populations, leading to the Sierra Nevada population being split off as its own species while the southern population retained the original name.
Which of these two frog populations has recovered better?
The Sierra Nevada yellow-legged frog has shown a more documented recovery, with a 2024 study finding substantial population increases across Yosemite National Park driven by trout removal and growing chytrid resistance, while the southern mountain yellow-legged frog's populations in southern California remain very small with far more limited recovery.
What caused both of these frog species to decline so severely?
Both species were devastated by the same two-part threat: trout introduced into naturally fishless high-elevation lakes for recreational fishing preyed heavily on the frogs' slow-developing tadpoles, and the amphibian chytrid fungus swept through surviving populations afterward, together eliminating more than 90 percent of historical populations across both species.