Researchers Set Up ‘Pitfall Traps’ to Click First-Ever Photos of California’s Most Elusive Creature

On November 1st, 2024, Vishal Subramanyan, Prakrit Jain, and Harper Forbes, the three student researchers from California, set forth on a trip into the dramatic Sierra mountains in Nevada. About 300 miles from San Francisco, the scenery unfolded into towering granite peaks and alpine lakes. With permits from the California Department of Fish and Wildlife, the three researchers crafted a small community between Mono Lake and the eastern gateway to Yosemite National Park.

With streams rushing around them, they set up camps in a wetland area and dug up a series of small holes. Inside the holes, they inserted plastic cups and baited these cups with “pitfall traps” filled with cat food and mealworms. Once the traps were set, they sat there and waited. Within just two hours, a tiny creature, as light as two paper clips and as tiny as the size of a palm, emerged from the bushes and hopped into the trap, getting caught, probably for the first time in the past 100 years, according to a report by the BBC.

Known by the name Mount Lyell shrew (Sorex lyelli), this creature is designated as a “species of special concern” in California. Although they have existed for the past 100 years, nobody had ever seen them before until this episode. Even when they were caught, they were never caught alive, almost always dead. The credit, researchers said, goes to their high-speed run. These little mouse-like critters with beady eyes and pointy noses run so fast that if you try to tame one by touching, they’ll bite. Despite their size, they have the metabolism of a dinosaur. If they don’t eat every two hours, they die.

This study was the first of its kind when these researchers, hailing from the University of California and the University of Berkeley, decided to capture the elusive creature on camera for the first time. Within the first two hours of their trap-setting, they spotted two shrews emerging from the hiding, usually damp tunnels lurking under alpine sedges. Once the shrew revealed itself, Subramanyan and his colleagues quickly captured it in portraits, excited to finally add its name to California’s mammal catalogue.

Subramanyan thinks these photographs look like a “recruitment poster of unglamorous wildlife.” The hardest part of getting the photos was one, they’re incredibly fast, because they are always running around, he told CBS News. While sitting around the camping site, the researchers kept on shuffling the location of the traps to avoid catching the same individuals again and again. The shuffling also enabled a broader map of where the shrews prowled. Analysis of the final collection of photographs and clips revealed that the creature measures only 9 to 10 centimetres and weighs just a few grams. Clips of the tissues taken from the tip of the tail confirmed its identity at the California Academy’s genetics lab.

Within the next three nights, the team photographer will observe 15 shrews of four different species: the montane shrew, Merriam’s shrew, vagrant shrew, and Mount Lyell shrew. “It was pretty much just go, go, go, and we never really slept for more than two hours at a time. And throughout the course of the three nights and four days, we probably never slept for more than eight hours 'cause we were just constantly trapping, photographing, then trapping again,” Subramanym told NPR. Subramanyan hopes that this study will raise awareness and encourage conservation efforts that will enable organisations to fight the extinction crisis and rapid biodiversity loss.

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