Scorpion Pincers and Stingers Fortified With Metals Tuned To How Each Species Hunts

by Clarence Oxford
Los Angeles CA (SPX) Apr 29, 2026
Scorpions carry some of the most formidable natural weapons found in the animal kingdom, from crushing pincers to venom-loaded stingers. Scientists have long recognized that trace metals reinforce these structures, but only a small fraction of the roughly 3,000 known scorpion species had ever been examined for this trait. A new study published April 28 in the Journal of the Royal Society Interface substantially broadens that picture by analyzing 18 species and revealing clear patterns in where and how those metals are distributed.

The research was led by scientists at the Smithsonian's National Museum of Natural History and the Smithsonian's Museum Conservation Institute, who used high-resolution electron microscopy and X-ray analysis to map metal enrichment at the microscopic scale across both the stingers and pincers of each species studied.

"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."

In the stinger, the analysis found zinc concentrated at the very tip of the needle-like aculeus. Immediately below that zone, manganese becomes the dominant metal, creating a sharp and visually distinct boundary between the two layers. The pincers showed an equally specific arrangement: in the movable outer segment known as the tarsus, researchers detected either zinc alone or a combination of zinc and iron, with these metals appearing only along the cutting edge -- precisely the region that endures the greatest stress during prey capture.

Scorpions vary considerably in how they deploy each weapon. Some rely heavily on stinging even when prey could be subdued by the pincers, while others wield oversized crushing claws and relatively modest stingers. The research team expected this behavioral variation to map onto the metal content of each weapon in a straightforward way, with stronger-crushing species showing higher zinc concentrations. The data revealed a more nuanced picture.

"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."

Counterintuitively, zinc appeared more frequently in species with longer, more slender pincers -- structures associated with less crushing force and a greater dependence on the stinger. That pattern implies that the function of a weapon, not merely the mechanical demands placed on it, shapes which metals are incorporated and in what configuration.

"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."

The study also establishes a standardized methodology for measuring metal enrichment that could be applied well beyond scorpions. The authors note that analogous studies could be conducted on other venomous or predatory arthropods, including spiders, wasps, ants, and bees, opening a broader inquiry into how metal incorporation has evolved across the tree of life in response to predation and defense pressures.

"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, research entomologist and curator of arachnids at the National Museum of Natural History and senior author of the study. "Not only does our work illustrate the material properties of scorpions' weapons, but it establishes a new approach towards analyzing the role of metal enrichment across the tree of life."

Research Report:Heavy metal predators: Diverse elemental enrichment across the weapons of scorpions