With help from Mexico, this rare frog is making a comeback in California 

In an inspiring amusement of cross-border teamwork, Mexican scientists person been astatine the forefront of restoring the uncommon California red-legged frog to immoderate muddy ponds successful Southern California — highlighting Mexico’s pivotal relation successful the revival of a taxon teetering connected the brink.

From a tiny bureau successful Ensenada, Baja California, biologist Anny Peralta and her squad astatine the nonprofit Fauna del Noroeste person devoted years to boosting the numbers of the frog, listed arsenic “endangered” successful Mexico and “threatened” successful the U.S.

Through painstaking situation restoration, they grew a frog colonisation successful Mexico’s borderlands from just 20 individuals to much than 400 — a lifeline for the taxon aft it vanished from 95% of its archetypal American range.

Working with U.S. scientists, Mexican teams engineered wetland habitats successful the Santa Rosa Plateau Ecological Reserve, a protected earthy country successful the Santa Ana Mountains successful southwest Riverside County, California.

By 2018, the Mexican squad was prepared to nonstop precious ovum masses north. Despite delays caused by the pandemic, Mexican pilots and researchers ensured the eggs made a cautiously regulated travel crossed the borderline and into the ponds to hatch arsenic tadpoles.

Then successful aboriginal 2025 came a payoff. Brad Hollingsworth, a San Diego herpetologist, utilized artificial quality to analyse lengthy audio recordings made astatine a California restoration pond.

California red-legged frogs coloring varies from reddish to green-brown, with diagnostic crimson markings connected their belly and little portion of the legs. (Chuck Peterson/Flickr)

Sifting done a chorus of owls, woodpeckers and coyotes, the AI investigation besides picked up the unmistakable grunt-like mating telephone of red-legged frogs — the archetypal grounds that Mexico’s eggs were thriving and breeding connected U.S. soil.

“It felt similar a large load disconnected my enarthrosis due to the fact that we were reasoning the task mightiness beryllium failing,” Hollingsworth said. “And past the adjacent mates nights we started proceeding much and much and more, and more, and more.”

Moreover, missing from the recordings was the dependable of the bullfrog, a taxon that, erstwhile introduced to the region, had helped hitch retired overmuch of the red-legged frog’s archetypal Southern California scope by outcompeting them for food, arsenic good arsenic infecting them. Drought, municipality maturation and predators besides reduced populations. 

Now, much than 100 adults populate Southern California ponds.

As clime alteration and borderline partition operation endanger to fragment habitats, Peralta underscores the binational effort. “They don’t cognize astir borders oregon visas oregon passports,” she said of the frogs. “This is conscionable their situation and these populations request to reconnect.”

The California red-legged frog is typically reddish oregon green-brown with irregular achromatic markings, unsmooth skin, and crimson coloring connected the undersides of its legs and belly.

The taxon (Rana draytonii) is believed to beryllium the prima of Mark Twain’s 1865 abbreviated story, “The Celebrated Jumping Frog of Calaveras County,” and their hind legs were eaten regularly during the California Gold Rush epoch (only to beryllium replaced as their numbers declined  by bullfrogs, which person adjacent bigger hind legs).

At 5 to 13 centimeters agelong (2 to 5 inches), red-legged frogs are the largest autochthonal frogs successful the occidental U.S. and erstwhile were recovered successful abundance up and down the California seashore and into Mexico. It is successful nary mode related to possibly Mexico’s astir celebrated amphibian, Señor Frog.

With reports from The Independent, Associated Press, La Verdad Noticias