Sierra Nevada Yellow-Legged Frog
Marshes, ponds, lakes, and meadows
Sierra Nevada mountains
Endangered (IUCN Red List)
This species is
to the Truckee Meadows.
Picture this: you're hiking through scenic Northern Nevada and you are fortunate enough to stumble upon a small (approximately 1.5 to 3.25 inch-long), brown- and yellow-spotted charismatic amphibian: a Sierra Nevada yellow-legged frog. This endangered animal can be easily recognized by the brown and yellow colored spots on its back that allows it to camouflage within its habitat. They gained their name “yellow-legged” from the bright yellow/orange coloration on their bellies and undersides of their legs. Until recently, biologists believed yellow-spotted mountain frogs and Sierra Nevada yellow-legged frogs were the same species. However, the two frogs are best distinguished by the slightly-shorter legs and unique mating call of Sierra Nevada yellow-legged frogs. Despite their small size, these frogs are expert hunters! They patiently wait for prey, which are usually tadpoles or small aquatic and land creatures, then lunge using their sticky, powerful tongues as an efficient trapping tool.
If you happen to see a Sierra Nevada Yellow-Legged Frog be careful because they emit a strong garlic/onion odor when disturbed!
The females of this species are typically larger than the males.
A female Sierra Nevada yellow-legged frog can lay anywhere between 100 to 350 eggs!
Sierra Nevada yellow-legged frogs, like most amphibians, prefer to make their homes in or near wetlands and are most often spotted on bare rocks close to a body of water. However, these frogs are unique due to the fact that they can survive the extremely cold temperatures of their habitats which are usually in high elevations (approximately 4,500 to 12,000 feet!). Additionally, they inhabit elevations as low as 3,500 feet in their northern habitats.
Years ago, Sierra Nevada yellow-legged frogs were abundant in various areas within Southern California, the northern areas of Lake Tahoe, and the high Sierra Nevada mountains. Their numbers were so great that people would have to constantly watch their feet when hiking trails! Today, however, their population has declined by approximately 90% in these areas.
The once bountiful Sierra Nevada yellow-legged frogs are now on the brink of extinction. This is primarily due to non-native fish that were and are introduced into the frogs' habitat and eat their eggs and tadpoles. Additionally, water and air pollutants such as pesticides and other chemicals are able to easily enter the frog’s porous skin thus causing mutations, low immunity, and other health problems. Lastly, a deadly fungus called chytrid causes a thick coating to grow on the outer layer of a frog’s skin and since frogs breathe through their skin, this fatal fungus causes the frogs to suffocate and die. The origin of the chytrid fungus and how it spreads is still unknown, but it is believed that the fungus lives on keratin, the same material that our nails are made of, and that can be found on the outer layer of adult frogs and the mouthparts of tadpoles.
U.S. Fish and Wildlife Service, Sierra Nevada Yellow-Legged Frog, 2020 Sierra Nevada Yellow-Legged Frog - Amphibians and Reptiles, Endangered Species Accounts | Sacramento Fish & Wildlife Office (fws.gov)
Center for Biological Diversity, Sierra Nevada Yellow-Legged Frog, 2020, Mountain and Sierra Nevada yellow-legged frogs (biologicaldiversity.org)
Center for Biological Diversity, Sierra Nevada Frogs and Toads Proposed Critical Habitat, 2020, Sierra Nevada Frogs and Toads Factsheet (biologicaldiversity.org) 4 Yosemite National Park Service, Sierra Nevada Yellow-Legged Frog, 2019, Sierra Nevada Yellow-Legged Frog - Yosemite National Park (U.S. National Park Service) (nps.gov) 5 GoneFroggin, Threats To Frogs: Pollution, 2017, Threat to Frogs: Pollution - (gonefroggin.com)
IUCN Red List, Rana sierrae, 2008, https://www.iucnredlist.org/species/136114/4240654.
Image: USFWS Pacific Southwest Region, https://www.flickr.com/photos/usfws_pacificsw/5662434480, license https://creativecommons.org/licenses/by/2.0/, cropped from original.
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