A photo of the creature graces the State of Montana’s online Field Guide. The page contains its common and scientific name, paruroctonus boreus. But curious readers mining for nuggets of natural history regarding the featured creature will have to look elsewhere. “We do not yet have descriptive information on this species,” it reads. “Please try the buttons above to search for information from other sources.”
As the only species of its kind found in the Treasure State, northern scorpions are known to only a precious few. Nonetheless, they are common in many areas of eastern Montana, though due to their nocturnal nature and diminutive bodies, few people ever encounter them. As scorpions go, northerners are on the modest end, size-wise. Adults range in length from around 1.5 to 2 inches, much larger than the tiny typhlochactas mitchelli, a cave-dwelling scorpion of Mexico measuring a mere 0.35 inches, but exceedingly smaller than the imposing hadogenes troglodytes, a monster scorpion of southern Africa that can grow to nearly 8 inches in length.
If a pair of Billings researchers have their way, the world will one day know much more about northern scorpions. Jim Barron, a professor at Montana State University-Billings, and Amy Weidlich, a former student, have been studying this reclusive arachnid for the past few years. Along the way they’ve learned how to most efficiently locate scorps in the field and keep them healthy in the laboratory.
On a warm, windy August night I accompany the pair and a student researcher on a midnight hunt west of Billings. The search hinges on one of the northern scorpion’s biological peculiarities: their body’s phosphorescent. Barron and his team tread slowly along a ledge above a sandstone precipice, shining flashlights that emit a particular spectrum of ultraviolet light. When the beam strikes a scorpion, its body glows in eerie greenish hues. Two hours later, we’ve captured nearly 30 scorpions, the researchers’ record for a night of hunting.
While we’re hunting specimens, the scorpions are hunting prey. Little is known about the species’ diet in the wild on a habitat-wide scale. But in southeastern Montana, Weidlich has observed northern scorpions on the hunt. “They eat a lot of moths and small, stingless wasps and flies,” she says. “They really like little caterpillars.”
Back at the lab, Weidlich drops a cricket (the equivalent of dog chow) into a scorpion’s container. The agile arachnid quickly corners the cricket, grasping it in the crab-like claw on its front leg. From a poised position over its back, its stinger pierces the cricket, immobilizing it with venom. The laboratory drama follows the same sequence used by hunting scorpions in the wild. It’s an infrequent spectacle. Scorpions can ingest a massive meal in a single sitting, allowing them to eat only once every two to three weeks.
Searching for northern scorpions in daylight hours is tough, but the Billings researchers have discovered one of the species’ favorite resting places in rangeland. How does the underside of a cow pie strike you as a summer home? Flip a dried cow plop in early August and a sharp-eyed observer might discover a female northern scorpion with tiny young clinging to her back. Scorpions are born alive and ride around on mom for about a week before venturing off to live on their own. Female scorpions in the lab birth an average of 23 babies per litter.
The northern scorpion’s range is the largest of any scorpion’s in North America (from Mexico to Alberta), yet they’re the least-studied species. How do they survive the winter? How long do they live in the wild? How might climate change affect their numbers? These are questions Barron and Weidlich hope to answer. I’m just wondering how to steal one of those cool blacklights from the lab.