Scorpions wield some of the natural world’s most formidable built-in weapons, from crushing pincers to venomous stingers. Scientists have long known that these structures contain trace metals that strengthen them, but only a small fraction of the roughly 3,000 scorpions had ever been examined for this trait.
A new study published April 28 in the Journal of the Royal Society Interface dramatically expands that understanding. Researchers at the Smithsonian’s National Museum of Natural History and the Smithsonian’s Museum Conservation Institute analyzed 18 scorpion species and uncovered striking patterns in the concentration and distribution of these metals.
“Scorpions are incredible hunters, and while we knew that metals strengthen the weapons in some species’ arsenals, we don’t know if all scorpions’ weapons contain metal, and if so, whether this metal enrichment relates to how they hunt,” said Sam Campbell, a graduate student fellow at the National Museum of Natural History at the time the research was completed. “We decided to use microanalytical techniques to unravel where and how these metals are distributed in the scorpions’ weapons to offer a clue as to how and why metal enrichment has been carried through the scorpion family tree.”
Scorpions use their pincers and stingers to defend themselves from predators and to subdue their prey. Across species, the reliance on each weapon varies widely. Some scorpions sting only when prey is difficult to subdue, while others use their stinger more aggressively. Some wield oversized, powerful pincers but relatively small stingers, while others show the reverse. Researchers suspected that these behavioral differences might correspond to how metals are distributed across each weapon.
Using high‑resolution electron microscopy and X‑ray analysis, scientists at the Museum Conservation Institute identified clear and highly localized patterns of metal enrichment in the scorpion’s weapons. In the stinger, they found that zinc is concentrated at the very tip of the needle‑like structure. Just below this point, manganese becomes the dominant metal, creating a sharp and visually distinct boundary between the two layers. A similarly specific pattern emerged in the pincers. In the movable outer segment, known as the tarsus, researchers detected either zinc alone or a combination of zinc and iron. Notably, these metals appeared only along the cutting edge of the pincer, reinforcing the parts that endure the most stress during prey capture.
“The National Museum of Natural History’s large scorpion collection allowed us to analyze metal enrichment in a wide range of scorpion species, more than have ever been studied before using these techniques,” said Edward Vicenzi, research scientist at the Museum Conservation Institute and a co-author on the study. “The microscopic-scale methods we used allowed us to identify individual transition metals in extremely high detail, showing us how nature skillfully engineered these metals in the scorpion’s weapons.”
Zinc Does Not Necessarily Equal Strength
The researchers expected species with stronger crushing pincers to contain higher levels of zinc. Instead, they found the opposite: zinc appeared more often in species with longer, slender pincers—structures typically associated with less crushing power and a greater reliance on stinging. “This points to a role for zinc beyond hardness, perhaps playing a bigger role in durability,” Campbell said. “After all, long claws need to grasp prey and prevent it from escaping before being injected by venom. This is an interesting finding because it suggests an evolutionary relationship between how a weapon is used and the specific properties of the metal that reinforces it.”
This research paves the way for investigating a host of unique scorpion adaptations. By standardizing how scientists measure enrichment, further research could examine metal enrichment in other arthropods, including spiders, wasps, ants and bees, answering questions about how organisms have adapted in response to predators and the need to hunt.
“By combining the National Museum of Natural History’s deep knowledge of scorpion taxonomy, morphology and behavior, and the Museum Conservation Institute’s expertise in microanalysis, we were able to efficiently and drastically expand our understanding of the evolution of metal enrichment in scorpions,” said Hannah Wood, a research entomologist and curator of arachnids at the National Museum of Natural History and the senior author of the study. “Not only does our work illustrate the material properties of scorpion’s weapons, but it establishes a new approach towards analyzing the role of metal enrichment across the tree of life.”
About the National Museum of Natural History
The National Museum of Natural History is connecting people everywhere with Earth’s unfolding story. It is one of the most visited natural history museums in the world. Opened in 1910, the museum is dedicated to maintaining and preserving the world’s most extensive collection of natural history specimens and human artifacts. The museum is open daily, except Dec. 25, from 10 a.m. to 5:30 p.m. Admission is free. For more information, visit the museum on its website , blog , Facebook , LinkedIn and Instagram .
About the Museum Conservation Institute
For 60 years, the Smithsonian’s Museum Conservation Institute (MCI) has advanced the preservation of cultural heritage that holds stories, histories, and memories critical to the human experience. Through innovative scientific research; trusted conservation practices; and responsive, effective training, MCI’s interdisciplinary team uses its knowledge and expertise to find scientific and cultural solutions to a broad range of questions related to the preservation of cultural heritage. For more information, visit mci.si.edu .
Journal of The Royal Society Interface
Experimental study
Animals
Heavy metal predators: Diverse elemental enrichment across the weapons of scorpions
28-Apr-2026