Whip Scorpions Look Scary but Don't Sting

Whip scorpion

Aukid Phumsirichat / EyeEm / Getty Images

Whip scorpions look fiercely threatening, by some accounts. In truth, they may be the scariest looking creatures that can't actually do you much harm. They resemble scorpions, with enormous pincers and long, whip-like tails, but they lack venom glands entirely. Whip scorpions are also known as vinegaroons.

What Whip Scorpions Look Like

Whip scorpions do look similar to scorpions but aren't true scorpions at all. They are arachnids, related to both spiders and scorpions, but they belong to their own taxonomic order, the Uropygi.

Whip scorpions share the same elongated and flattened body shape as scorpions and possess oversized pincers for catching prey. But unlike a true scorpion, a whip scorpion does not sting, nor does it produce venom. Its long, slender tail is likely just a sensory structure, enabling it to detect vibrations or odors.

Although smaller than most true scorpions, whip scorpions can be impressively big, reaching a maximum body length of 8 cm. Add another 7 cm of tail to that, and you've got a big bug (though not an actual bug). Most whip scorpions inhabit the tropics. In the U.S., the largest species is Mastigoproctus giganteus, sometimes known as the mule killer.

How Whip Scorpions Are Classified

  • Kingdom – Animalia
  • Phylum – Arthropoda
  • Class – Arachnida
  • Order - Uropygi

What Whip Scorpions Eat

Whip scorpions are nocturnal hunters that feed on insects and other small animals. The first pair of a whip scorpion's legs are modified into long feelers, used for locating prey. Once a potential meal is identified, the whip scorpion grabs the prey with its pincers and crushes and tears its victim with powerful chelicerae.

The Life Cycle of Whip Scorpions

For a creature with such a frightening appearance, the whip scorpion has a remarkably tender love life. The male caresses his potential mate with his front legs before presenting her with his spermatophore.

After fertilization occurs, the female retreats to her burrow, guarding her eggs as they develop in a mucous sac. When the young hatch, they climb onto their mother's back, holding fast with special suckers. Once they molt for the first time, they leave their mother and she dies.

Special Behaviors of Whip Scorpions

While they can't sting, whip scorpions can and will defend themselves when threatened. Special glands at the base of its tail enable the whip scorpion to produce and spray a defensive fluid.

Usually, a combination of acetic acid and octanoic acid, the whip scorpion's defensive spray gives off a distinctive vinegar-like smell. This unique odor is why the whip scorpion also goes by the nickname vinegaroon. Be forewarned. If you encounter a vinegaroon, it can hit you with its defensive acid from a distance of a half-meter or more.

Other Types of Whip Scorpions

The order Uropygi isn't the only group of organisms known as whip scorpions. Among the arachnids are three other orders that share this common name, briefly described here.

  • Micro Whip Scorpions (Order Palpigradi): These tiny arachnids live in caves and under rocks, and we don't yet know much about their natural history. Micro whip scorpions are pale in color, and their tails are covered with setae that function as sensory organs. Scientists believe micro whip scorpions prey on other microarthropods, or perhaps on their eggs. About 80 species are described worldwide, although many more likely exist, still undiscovered.
  • Short-Tailed Whip Scorpions (Order Schizomida): The short-tailed whip scorpions are small arachnids, measuring less than 1 cm long. Their tails are (predictably) short. In males, the tail is knobbed so the mating female can hold onto it during mating. Short-tailed whip scorpions often have modified hind legs for jumping, and look superficially similar to grasshoppers in that regard. They prey on other small arthropods, hunting at night, despite poor eyesight. Like their larger cousins, short-tailed whip scorpions spray acid in defense but lack venom glands.
  • Tailless Whip Scorpions (Order Amblypygi): Tailless whip scorpions are just that, and the name of their order, Amblypygi, literally means "blunt rump." The largest specimens reach 5.5 cm in length and look somewhat similar to the larger vinegaroons. Tailless whip scorpions have strikingly long legs and spiny pedipalps, and they can run sideways at startling speeds. These features make them the stuff of nightmares to the easily spooked among us, but like the other whip scorpion groups, tailless whip scorpions are benign. That is, unless you're a smallish arthropod, in which case you may find yourself impaled and crushed to death by the tailless whip scorpion's powerful pedipalps.

Sources:

  • Bugs Rule! An Introduction to the World of Insects, by Whitney Cranshaw and Richard Redak
  • Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson
  • "Species." Bugguide.net.