Tadpoles Fashionably Late to the Pool Party

September 15, 2017

photos of toad tadpoles in a pond
Katy Delaney spotted these Western toad (Bufo boreas) tadpoles in November.  photo: Katy Delaney

Exactly two years ago, an unusual summer storm drenched Southern California, making it the second wettest September day ever recorded in Los Angeles. It caused flooding, power outages, and evacuations from leaky buildings. But it also caused a stir in the Western toad population.

Western toads (Bufo boreas) are found from Baja California all the way to Alaska and from sea level to 12,000 feet in elevation. These toads usually breed in late winter and spring, when winter rains fill the ponds they need to do the deed. But in the midst of a record-breaking drought, the rain never showed up in early 2015, so the toads didn’t have a chance to breed.

With the normal breeding season long past, it seemed that 2015 just wasn’t going to work out for these toads, but in the aftermath of this unexpected late summer storm, they apparently decided to seize the rainy day.

Two months later, Katy Delaney, an ecologist with the National Park Service, spotted Western toad tadpoles in a shallow pond in the Santa Monica Mountains. Seeing tadpoles in November is practically unheard of.

“It was a strange sighting,” noted Delaney. “I thought to myself, ‘It’s the completely wrong time of year for this.’”

Delaney snapped a photo and uploaded it to iNaturalist, contributing the sighting to the RASCals Project (Reptiles and Amphibians of Southern California), headed by NHMLA Herpetology Curator Greg Pauly.

a photo of a pond with little dots at the edges, which are tadpoles
The pond where Delaney spotted the tadpoles at the edges.  photo: Katy Delaney

“To the best of my knowledge, this is the latest observation of Western toads breeding,” said Pauly. "Western toads are a relatively common species, but we still lack a basic understanding of their biology. This goes to show how much we still have to learn about even the common species that surround us."

And luckily for the tadpoles Delaney found, the winter here in Southern California was mild enough for these oddly-timed tadpoles to grow and survive. At higher elevations or farther north, it would probably be too cold for these young toads to have made it through the winter.

After all, it’s Southern California. We’re not known for our punctuality. It’s quite alright to be fashionably late to the pool party.

Pauly and Delaney published the findings in the Bulletin of the Southern California Academy of Sciences.  

Seen a snake? Looked at a lizard? Found a frog? Tracked a toad? Take a picture and upload it to iNaturalist. Find out how!


(Posted by: Katie McKissick)

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