The most reliable way to tell a male scorpion from a female is to flip it over and look at the pectines, a pair of comb-like sensory organs on the underside of the body just behind the last pair of legs. Males have longer, wider pectines with more teeth than females. Beyond the pectines, differences in body shape, tail length, and pincer proportions can also help you identify sex, though these vary by species.
Check the Pectines First
Pectines are the single most useful feature for sexing a scorpion. They look like two small combs attached to the underside of the scorpion’s body, pointing backward from the area between the last pair of legs. Both males and females have them, but males consistently have larger pectines with more individual teeth along each comb.
In the species Scorpio maurus, for example, males average about 12.5 to 12.9 teeth per pectine while females average 12.0 to 12.1. That difference sounds small, but when you look at the pectines side by side, the male’s are visibly longer and wider. Emperor scorpions (Pandinus imperator), one of the most commonly kept pet species, have pectinal tooth counts ranging from 13 to 18, and males sit at the higher end of that range.
To examine the pectines, you’ll need to safely turn the scorpion onto its back. For pet scorpions, gently coaxing the animal into a clear container and then flipping the container works well. A magnifying glass or even a phone camera on zoom helps you count the individual teeth along each comb. If the teeth are numerous, closely spaced, and the combs extend well past the leg bases, you’re likely looking at a male.
Compare Body Shape and Size
Females tend to be wider and stockier than males of the same species and age. In Scorpio maurus, females average a wider body (1.6 mm vs. 1.5 mm across the mesosoma) and a longer carapace (8.0 mm vs. 7.5 mm). Males, by contrast, are typically more slender overall. This pattern holds across many scorpion families: females are built heavier, likely because their bodies need to support developing offspring, since scorpions give live birth and carry young on their backs.
The catch is that size alone isn’t enough. You need to compare scorpions of the same species and similar age. A well-fed subadult male can easily look bulkier than a lean adult female, so body shape works best as a supporting clue rather than your primary method.
Look at the Tail and Pincers
Males generally have longer tails (the segmented section called the metasoma) relative to their body length. Research across multiple species confirms this pattern. In Centruroides margaritatus, the main sexually dimorphic traits are body size (females larger) and tail length (males longer). Arizona bark scorpions (Centruroides sculpturatus) show pronounced tail length differences between the sexes, making it one of the easier species to sex visually.
Pincers also differ, though the pattern depends on the species. In burrowing scorpions like Opistophthalmus karrooensis, females have wide, thick pincer segments while males have more elongated, slender ones. The logic mirrors the body shape difference: females in many species develop robust pincers for digging and defense, while males develop longer appendages that help during courtship grasping. If you’re keeping a common pet species, look up the specific pincer pattern for that species, since the direction of the difference isn’t universal.
The Genital Operculum
Directly in front of the pectines, on the scorpion’s underside, you’ll find the genital operculum: a pair of small plates covering the reproductive opening. In males, these plates are slightly separated or can be gently nudged apart, revealing a small gap between them. In females, the plates are fused together or overlap tightly and resist separation. This method requires a close look and, ideally, a magnifying lens, but it’s considered very reliable once you know what to look for.
The shape of the operculum also differs subtly. Female genital opercula tend to be broader and have small internal cavities that receive part of the male’s sperm packet during mating. You won’t see those cavities from the outside, but the overall wider, flatter profile of the female’s operculum compared to the male’s narrower one can be a helpful visual cue.
Behavioral Clues During Mating Season
If you’re observing scorpions in the wild or keeping a pair, behavior can confirm what anatomy suggests. Males are the ones that initiate the mating dance, a courtship ritual where the male grasps the female by her pincers and walks her back and forth in what researchers call a “promenade à deux.” He leads, she follows (or resists). Males also perform specific calming behaviors during this dance, including rubbing the female with their legs or tapping with their tail, all meant to reduce her aggression long enough for mating to succeed.
Males tend to be more active and mobile in general, especially at night during breeding season. They wander farther from shelter searching for mates. If you see a scorpion moving purposefully across open ground, there’s a reasonable chance it’s a male on the hunt for a partner.
Age Matters for Accuracy
All of these methods work best on sexually mature scorpions. Juveniles are difficult to sex because the dimorphic traits haven’t fully developed yet. Pectinal teeth are present from birth, so tooth count can give you an early indication, but the size differences in pectines, tails, and pincers become much more obvious after the scorpion has gone through several molts. Most species reach sexual maturity somewhere between one and three years of age, depending on species and environmental conditions.
For the most confident identification, combine multiple methods. Check the pectines for tooth count and overall size, look at the genital operculum for plate separation, and then assess body proportions. Any single trait can overlap between sexes in some individuals, but when two or three indicators point the same direction, you can be confident in your call.