That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

As is true for tarantulas, reptile enthusiasts (myself included) are often interested in scorpions.  Today I would like to provide an overview of these most ancient of animals (they were likely the first creatures to leave the sea for a terrestrial existence), with specifics concerning some readily available species to follow next time.

Please Note:  All scorpions manufacture venom and are capable of delivering a painful sting. Human fatalities are rare but not unknown, and the venoms of many are relatively unstudied.  Also, an allergic reaction is always possible…during my years at the Bronx Zoo I was often in contact with scorpion researchers….some reported relatively severe reactions from species not known to be dangerously venomous.

Unfortunately, the trade in scorpions is not well-regulated, and highly venomous species do appear from time to time (I’ll relate a personal experience in Part II of this article).  Purchase scorpions only from reliable sources, and be sure you can identify the species you are considering.  That being said, some of those best-suited to captivity are not dangerous, and make fascinating terrarium subjects.  Please check the legalities of scorpion ownership before acquiring one, as such is regulated in some areas.

Do not grab scorpions by hand, despite what you may see others do.  To move a scorpion, use a long handled stainless steel hemostat to gently grasp the telson (“tail”).  A bit of foam rubber should be secured to the tips to prevent the scorpion from being injured. 

Classification

Scorpions are classified in the order Scorpionidae, and, along with spiders, ticks and mites, in the Class Arachnida.  Nearly 2,000 species have been described (as opposed to 40,000+ spiders), ranging in size from .3 to 8.5 inches in length.  The 4 inch long Cetrruroides gracilis is the largest species in the USA, while the South African flat rock scorpion (Hadogenes troglodytes) is the world’s longest and heaviest.

Range and Habitat

Scorpions are found in tropical, sub-tropical and (less commonly) temperate regions of all continents except Antarctica, and are absent from New Zealand.  Various species are adapted to live in deserts, open forests, grasslands, caves and rainforests.  Some are quite at home around people, and may be found in overgrown fields, agricultural areas, gardens, parks and even within homes.

A surprising number thrive in quite cold climates, ranging as far north as Canada and southern Illinois in North America.  A feral colony of a small African species, introduced in produce shipments, is established in southern England.  In the USA, scorpions reach their greatest diversity in the southwest, where 60+ species may be found.

Diet

All are predacious, with most consuming soft-bodied insects but some specializing in land snails, sowbugs and other scorpions.  Larger species may take frogs, lizards, shrews and other sizable animals on occasion.

Reproduction

All scorpions thus far studied give birth to live young, and a number are parthenogenic.  Females typically carry the soft, relatively defenseless young on their backs for a time.  Many species feed their offspring with shredded insects…in some the young are totally dependant upon their mothers for food and will perish if separated too quickly.

In contrast to most of their spider relatives, certain species, including the popularly kept emperor scorpion, are quite social and may be housed in colonies.

Venom

Scorpion venoms are not well-studied, but thought to be quite complex.  Some that have been analyzed have yielded compounds with potential medicinal value.  Most seem to be neurotoxic in nature, but cytotoxic varieties are known as well.

The larger scorpion species are generally not dangerous to people, while some of the very small ones have caused fatalities.  Most of the 25-30 species thought to be capable of delivering serious stings are classified within the Genera Centruroides, Androctonus and Tityus.  However, as we have limited knowledge of scorpions in general, all should be treated with caution.  As mentioned, the possibility of allergic reactions to even weak venoms is always a possibility.  In all cases, small, straw-colored scorpions from the Middle East and North Africa should be avoided.

Scorpions in Captivity

At least 15 species are well-established in captive breeding populations, and many others are regularly available.  Fortunately, one of the largest and most interesting, the emperor scorpion, is also quite benign.  It lives well in groups, and females are surprisingly attentive to their young.  Next time I’ll write about the care of this and other popular species.

A short introduction to scorpion ecology, along with a diagram of their body parts and photos of common species of the American Southwest, is posted at:

http://wc.pima.edu/~bfiero/tucsonecology/animals/arth_scorpions.htm

A recent article (Jan. 2009) in Physiological and Biochemical Zoology has shed light on why spitting cobras nearly always hit the eyes of whatever creature they are aiming for, be it secretary bird (a predator), gnu (a trample hazard) or person.

Perfect Aim Not Needed

Utilizing high speed photography and EMG tests, researchers established that the snakes contract their head and neck muscles just before ejecting venom.  The contractions rotate the head and jerk it sharply from side to side, so that the venom forms a complex geometric spray pattern as it approaches its target.  As long as aimed in the general direction of the face, the venom contacts the adversary’s eyes nearly 100% of the time.

Keeping Zookeepers on Their Toes

I have worked closely with several types of spitting cobras.  Like many Elapids (cobras and their relatives), they are alert and quick-moving, and seem, at least on the surface, to be quite intelligent.  These traits, combined with their ability to both bite and “spit”, renders them quite a handful in captivity, and they provide much fodder for zookeepers’ tales.

Perhaps He Thought They Needed Exercise?

In one very bizarre incident from my Bronx Zoo days, a visitor held his son up so that the child could kick in the glass of an exhibit housing 3 black-necked spitting cobras (Naja nigricollis)!  As might be expected, the breaking glass caused a great deal of agitation to both the snakes and some of the other visitors…I say “some of” because nearly as many people were pushing towards the exhibit as were running away (those wacky New Yorkers!).  Fortunately, all emerged unscathed, and the snakes were recovered quickly.

Cobra Hunting to Start the Day

Another zoo adventure began when, still bleary-eyed after a few mugs of espresso very early one spring morning, I discovered that 3 red spitting cobras (Naja pallida) had vacated their holding cage overnight.  The ancient plastic goggles I used around spitters were fine for exhibit work, but rendered me nearly blind in the dim, cluttered recesses of the reptile house’s basement and storage areas.  Lifting the goggles briefly to peek under something was terrifying, but so was leaving them on and seeing only unidentifiable shadows.

One colleague, goggles perched on his forehead, spied a snake and grabbed it with tongs, neglecting to lower the goggles in the excitement.  Fortunately, the trapped serpent vented its wrath by biting the tongs, and not by spitting at my partner’s face!  After a few sweaty, suspense-filled hours, all 3 snakes were re-captured…whereupon I ordered new goggles!

I’ve also had run-ins with the spitting cobra’s much larger relative, the king cobra…please see my article A Close Call With a King Cobra http://blogs.thatpetplace.com/thatreptileblog/2008/06/ for more cobra tales.

Image referenced from Wikipedia, first published by LA Dawson, and shared under the Creative Commons Share Alike-2.5 License.