A Fearsome Little Delicatessen

We actually hit 15 degrees (F, that is) today -- at midnight! So here's a zoo shot, and a brief discussion:

Giant Whipscorpion (Mastigoproctus giganteus),
Cincinnati Zoo, Hamilton Co, OH 3/29/2012

This is a Giant Whipscorpion (Mastigoproctus giganteus), also known as a Vinegaroon. He's a fearsome critter, reaching about 3 inches in length. Despite the name Whipscorpion, they can't sting, although since they're predators of other arthropods, they can inflict a rather painful bite. They're found from Arizona to Oklahoma, and in Florida, and then south into Mexico, but since they're strictly nocturnal, (1) most people never see them.

So where does the name Vinegaroon come from? While they don't have a scorpion's venom, they do utilize a chemical weapon of a sort. When threatened, they can expel a fine mist composed of water and several organic acids. The primary component is actually acetic acid (85%), which is also the main acid in vinegar. (2) I've never encountered it, but I imagine that they must actually smell like a spring salad when they use the stuff. This isn't going to do more than irritate something the size of a human, and apparently it's most effective if it hits the eyes -- but then, the eyes are usually pretty close to the mouth, so I guess it works well enough.

I usually figure a good rule for handling critters is this: if you're not sure it's harmless, then assume it isn't! But this guy's fearsome appearance actually masks a relatively harmless reality. As Terry Pratchett, Ian Stewart, and Jack Cohen put it, Nature certainly knows how to lie. (3)

(1) Punzo, F. (2006). Types of shelter sites used by the giant whipscorpion Mastigoproctus giganteus (Arachnida, Uropygi) in a habitat characterized by hard adobe soils. Journal of Arachnology, 34(1), 266-268.

(2) Schmidt, J. O., Dani, F. R., Jones, G. R., & Morgan, E. D. (2000). Chemistry, ontogeny, and role of pygidial gland secretions of the vinegaroon< i> Mastigoproctus giganteus</i>(Arachnida: Uropygi). Journal of insect physiology, 46(4), 443-450.

(3) Pratchett, T., Stewart, I., and Cohen, J. (1999) The Science of Discworld. EBURY PRESS/Random House, London