Paleontologists Discover a New Species of Ice Age Toad at the La Brea Tar Pits, Offering Clues About the Area’s Ancient Climate

The fossilized remains, recovered in 1929, were part of La Brea’s relatively understudied amphibian collection. Since toads are cold-blooded and sensitive to environmental changes, the discovery can help researchers piece together past climate conditions

Margherita Bassi | Daily Correspondent

August 27, 2026 11:37 a.m.

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Over the past tens of thousands of years, the La Brea Tar Pits in modern-day Los Angeles became the final resting place for millions of animals that got stuck in its dark, sticky pools. Today, some of the fossil site’s most famous victims include mammoths, giant ground sloths, dire wolves and saber-toothed cats.

But tiny creatures also met their doom in the bubbling pits of asphalt. Now, these often overlooked animals are spilling secrets about what southern California looked like long ago.

In a study published August 4 in the Journal of Vertebrate Paleontology, researchers have identified a fossil of a never-before-seen species of spadefoot toad. This creature, dubbed Spea labreae after the tar pits, is the first extinct Ice Age amphibian found at La Brea and only the second discovered in North America.

“I’m very happy, very excited, because it’s my first new species in all my career,” study co-author J. Alberto Cruz, a paleoecologist at La Brea and Mexico’s National Institute of Anthropology and History, tells Scientific American’s Damien Pine. 

A few years ago, Cruz began to analyze La Brea’s relatively understudied reptile and amphibian collections. But some unusual-looking specimens stumped him. He initially thought they might have belonged to a sick or injured animal, according to a statement.  

So he and his co-author Emily Lindsey, also a paleoecologist at La Brea, compared the remains—recovered in 1929—to others in the collection. They also looked at fossils at the Natural History Museum of Los Angeles County and the Museum of Vertebrate Zoology at the University of California, Berkeley.

Unique features in the fossilized bones hinted that they came from a previously undescribed species: S. labreae. It’s an important addition to the fossil record because delicate skeletons of toads and other frogs don’t fossilize easily, so they’re rarely unearthed outside of asphaltic goo.

“It is surprising that relatively few frog fossils have been previously recovered from La Brea, and I’m confident more will turn up,” David Blackburn, curator of amphibians and reptiles at the Florida Museum of Natural History, who didn’t participate in the study, tells CNN’s Taylor Nicioli.

Researchers don’t know exactly how old the toad is, since they’d have to use a destructive technique to find out. But based on other remains found in the pool of tar where it was found, the team suspects it lived at least around 45,000 years ago, during the last Ice Age, which took place around 11,700 to 2.6 million years ago, reports Scientific American.

What’s more, unlike larger animals that can move when environmental changes cause problems, amphibians stay put because they must remain near water. That means La Brea was once wet. Additionally, toads are cold-blooded and rely on their surroundings for heat, so their presence offers clues about ancient climates, Cruz tells Scientific American.

“If you change the environment, you change the vegetation, the climate is warmer or colder, it affects these animals directly,” he says in the statement.

S. labreae isn’t the only intriguing amphibian that Cruz and Lindsey uncovered. They also identified the remains of a Mexican burrowing toad, an animal that previously had not been documented at La Brea.

Unlike its extinct cousin, Mexican burrowing toads are still alive. But today, the nearest populations are in southern Mexico some 1,500 miles from Los Angeles, suggesting that the animal’s range has significantly changed since the recovered individual met its gooey death.

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.