A scary-looking but mostly harmless arachnid — black, up to 3 inches, with massive pincers and a long whip-like tail. Sprays acetic acid (vinegar) when threatened — hence "vinegaroon" — but has no venom.

Also called: Whip Scorpion, Mule Killer (folk myth; harmless), Grampus

Native status: Native to southern US and Mexico

§ Quick facts

SizeBody 25–80 mm; whip-like tail 50+ mm
Weight5–25 g
LifespanWild 4–7 years
OrderThelyphonida
FamilyThelyphonidae

§ Encyclopedia

Mastigoproctus giganteus, the giant whip scorpion, also called the giant vinegaroon, grampus, or Texas Giant Vinegaroon, is a species of whip scorpions in the family Thelyphonidae. Its native range is from the Southern United States to Mexico.

Source: Wikipedia — Mastigoproctus giganteus Licensed under CC BY-SA 4.0

§ Identification

Field marks. Large dark brown to black arachnid (looks like a scorpion crossed with a spider); massive pedipalps; long thin whip-like tail (not a sting); eight legs but first pair used as sensory feelers.

Similar species. True scorpions (curved tail with sting). True spiders (no segmented abdomen or whip tail). Tailless whip scorpions (no whip tail).

Voice. Hissing during vinegar spray defense.

§ Diet & behavior

Diet. Insects, spiders, scorpions, other arachnids. Crushes prey with massive pedipalps.

Behavior. Despite frightening appearance, completely harmless to humans — no venom. When threatened, sprays a vinegar-like mixture (85% acetic acid plus other acids) from glands at the base of the tail-like flagellum, accurate to ~30 cm. The spray is the source of the common name "vinegaroon" and is genuinely effective at deterring predators; the smell can persist on hands or clothing for days. Females carry egg sacs attached to the underside of the abdomen and tend hatched young until first molt.

§ Range

Southern US (especially Texas, Arizona, New Mexico) into Mexico

§ Habitat

Deserts, dry grasslands, rocky outcrops

§ Threats

Habitat loss to suburban development, fear-driven killing, pesticides.

§ Conservation status

According to the IUCN Red List, the giant whip scorpion (vinegaroon) is currently classified as Least Concern.

§ What helps

Skip pesticides. Don't kill (they're harmless). Support desert habitat conservation.

Support our work More ways to help

§ Further reading

§ Sources cited

  • American Arachnological Society
  • Texas A&M AgriLife Extension
  • BugGuide