Whipscorpion, any of a group of arachnids characterized by a whip-like tail and the ability to spray acetic acid at attackers. They are also called vinegaroons, because of their vinegar-like defensive spray, and uropygids, after their order. Whipscorpions live under leaf litter or rocks and hunt small arthropods and other invertebrates. They range throughout tropical and subtropical Asia and the Americas. There are about 100 species.
The front section of the body, or cephalothorax, of the whipscorpion is covered by a carapace, or shell-like case . The whipscorpion has one pair of eyes toward the front of the cephalothorax and three or four pairs to the side. Its large chelicerae, or jaws, resemble the claws of a crab and are composed of several hinged segments. The chelicerae grasp and shred small prey and then transfer it to the pedipalps, or leg-like mouthparts. The foremost pair of walking legs is longer and more slender than the other three, and these legs are used like antennae to detect prey and to explore the environment ahead.
Whipscorpions breathe through two pairs of layered lungs, called book lungs, on the abdomen. The whiplike telson, or tail, is sensitive to light, which the whipscorpion avoids. At the base of its telson, the whipscorpion has two glands that are capable of spraying acid at predators. The acid is mostly acetic, which has a vinegar smell, and is accompanied by a small amount of caprylic acid, which helps the acetic acid pass through the exoskeleton, or outer skin, of other arthropods. The acids can also burn human skin and eyes, although the amount ejected by the whipscorpion is not dangerous.
Male and female whipscorpions are outwardly similar. During reproduction, sperm is transferred indirectly: the male deposits a spermatophore, or sperm sac, on the ground and gently guides the female over it by grasping her sensory pedipalps. He may assist her in taking the spermatophore into her genital opening by using his pedipalps. The female stays in a sheltered spot, brooding her eggs in a silken sac until they hatch.
In captivity, whipscorpions are docile and rarely squirt acid. The giant whipscorpion, common in Florida and the southwestern United States, is sometimes sold in pet stores. It is the largest species in the order and may grow to about 8 cm (3.15 in) in body length.
Scientific classification: Uropygids are in the order Uropygi, class Arachnida, phylum Arthropoda. As arachnids, their relatives include true spiders, true scorpions, and the ticks and mites. Whipscorpions should not be confused with tailless whipscorpions or with windscorpions, two separate arachnid orders. The giant vinegaroon is Mastigoproctus giganteus.