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aScorpions are an ancient group, remaining relatively unchanged since they became one of the first animals to crawl onto land about 400 million years ago. Anatomically, scorpions have a cephalothorax (combined head and thorax) containing their two pedipalps (pincers) and 8 legs and a metasoma ("tail") of 5 segments that is part of their abdomen. The pedipalps double as sensors (making up for their poor eyesight) and to grasp prey (usually other arthropods that they have ambushed). After grasping their prey, they sting it using their telson (stinger) and "chew" it up with their chelicerae. Beneath the scorpion, sweeping the ground, are a pair of pectines (comb-like structures) that likely function to detect odors and for the male to find an adequate surface to deposit his packet of sperm (spermatophore) for the female to pick up during their courtship "dance".

Scorpion courtship is potentially dangerous, because each potentially could become the prey of the other. Therefore, scorpion courtship includes grasping each other's pedipalps and maneuvering around in a way that looks like they are dancing. The male searches for a good place to deposit his spermatophore (sperm packet), then "dances" his partner around to the spot so that she can pick up the spermatophore. The sperm then can be saved for a year until she uses it to fertilize her eggs. But scorpions do not lay eggs, instead they give birth in the summer to live young that hop onto their mother's back and ride around for the 1-3 weeks until their first molt.

Scorpions are most active at night (nocturnal); thus it is difficult to watch them going about their business. A good way to watch scorpions is to use a black light at night. One or more substances in the epidermis (outer skin) of our scorpions fluoresce a greenish-yellow color, making it easy to spot them. If you are lucky, you may witness scorpions ambushing their prey or courting their mates.

Tucson's Common Scorpions

stripe-tailed scorpion
stripe-tailed scorpion