California Red-Legged Frog

In July 2014 California got a state amphibian: the California red-legged frog. Here's what Mark Twain's "Celebrated Jumping frog of Calaveras County" is all about.

by Brendan Bane

The California red-legged frog, Rana draytonii, is the state’s official amphibian as of July 7, 2014. With this designation comes first-rate protection and recognition; students who learn of California’s grizzly bears and saber-toothed cats will now also learn the name and natural history of our red-thighed, web-toed, largest native true frog (family Ranidae). But the red-legged frog did not earn its honors without sacrifice; the amphibian was nearly eaten into extinction and is still outcompeted by invasive species.

Find the red-legged frog near streams and creeks in woodlands, grasslands, wetlands, and scrublands. Their smooth olive, brown, red or gray skin is speckled with black splotches. Those signature red legs are rosy underneath, and as the frog ages, that redness spreads out toward the belly. Their range extends along the coast from Northern to Baja California, reaching slightly inland to curve around the central valley. They once thrived further inland toward the foothills of the Sierra Nevada mountains (Daniel Webster, the athletic amphibian in Mark Twain’s story “The Celebrated Jumping Frog of Calaveras County,” is a red-legged frog). Then people became the frog’s first plague; gold miners of the 19th century devoured them at an estimated rate of almost 80,000 frogs daily!

Today, the California red-legged frog is ranked as America’s fourth most threatened frog. Pesticide pollution, habitat destruction and invasive species are its greatest threats. The introduced bullfrog poses a particularly sexy impediment: male red-legged frogs apparently find female bullfrogs more attractive than those of their own species, and thus squander their efforts on mates that never bear red-legged fruit. Elkhorn Slough National Estuarine Reserve researcher Nina D’Amore says of the misguided suitors, “I’ve seen them hanging on to limp, dead juvenile bullfrogs. I’ve seen them hang on for 10 days, and they’re wasting their time.”

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Amphibian enthusiasts should note the distinction between the California red-legged frog and its cousin, the northern red-legged frog. Scientists once assumed the two were subspecies until closer inspection revealed the difference: Northern red-legged frogs have one or no vocal sac while our state amphibian sports two, which it uses to emit its distinctive mating call (uh-uh-uh-uh…grrrr). Listen here.

Watch a California red-legged frog's lightning-fast feeding technique in this short video by Gary Nafis.