The Emperor Scorpion, Pandinus imperator (C.L. KOCH)
in Captivity Part I: Basic Care and Maintenance
By:Lucian K. Ross

General discussion
Although my primary arachnocultural interests are African and Old World arboreal tarantulas, I have always maintained Emperor scorpions in my arachnid collection over the past seven years. My interest in these large West African scorpions began in 1997 with the publication of Gaban (1997). After reading and re-reading this article over the period of a month, I felt I had enough basic knowledge to keep this species in captivity and acquired four mature female specimens from a local pet store.

Since August 1997, I have had 12 mature specimens in my collection and 52 nymphs from 3 successful matings (number of offspring: 11, 22, and 19). I also had a large wild-caught, gravid female that produced 17 offspring after four months in captivity.   Although the four original specimens, along with all of the captive-reared and all but six of the captive-bred offspring, have been passed on to friends and fellow enthusiasts as gifts, I still maintain eight large mature

females from my first (6) and second (2) captive breedings and I have recently acquired three small, wild-caught males from a local pet store. In my opinion, only Hadogenes (Africa) and Heterometrus (Asia) can compare with the interest and beauty of the large, robust scorpions of the genus Pandinus.

Before I begin, let me state that even though the majority of specimens of P. imperator are non-aggressive, adapt well to captivity, and seem reluctant to sting, I do not advocate or endorse the handling of any scorpion species due to the possibility of injury to the scorpion and/or the handler. Although no reports exist to indicate that the venom of this species is medically significant to humans, all specimens are capable of delivering powerful attacks with their pedipalpal chela (claws) and painful multiple stings. The handling of such animals should be undertaken as a personal choice made by each individual enthusiast based upon his/her knowledge and understanding of each individual specimen in their collection.

If you do decide to attempt to handle your Emperor, your initial handling attempt should be done in a quiet area with no disturbances to distract your attention. Allow the scorpion to move freely into your outstretched hand and do not block its movements while being handled. Keep your hands within several inches of a soft, flat surface - in case your Emperor falls from your hand. If you're handling your Emperor over a tabletop or similar hard surface, place a folded towel or sheet over the area to provide a soft surface in case your Emperor falls.

Emperor scorpions are typically black in overall colouration, but brownish and greenish coloured specimens are not uncommon. Although reports state that specimens may attain total lengths of 8" (20 cm), the majority of specimens range in size between 6"-7" (15-18 cm). Males and females typically mature in 6-7 moults within 14-22 months (in captivity) depending on environmental conditions, feeding frequency and diet. To date, I've never had offspring produced from female specimens smaller than 6" (15 cm). All females that produced offspring from captive matings were 6"-6.5" (15-16 cm) in length.

Male and female specimens possess large, thick, granular pedipalpal chelae (claws) with a sparse covering of sensory setae. Their large chelae are capable of delivering painful attacks that may break the surface of the skin. In the majority of specimens, the telson ("stinger") is brownish to brownish-red in colouration with sparse setae on the external surface. Although most are hesitant to sting, all are capable of delivering multiple stings when annoyed. However, most specimens will choose to rely on their powerful chelae to defend against perceived threats.

Male and female Pandinus imperator exhibit primitive social behaviour and several similarly sized specimens can be safely maintained in a communal set-up if the vivarium offers ample floor space, a moderate depth of substrate and multiple retreat options. Although rare, if you notice one specimen in the community is continuously attacking other members of the group then, remove that scorpion to a separate vivarium.

Vivarium set-up

The following standard size glass vivaria are recommended to maintain single and multiple specimens of P. imperator:

Single specimen:

10-Gallon (37L) glass vivaria - 20" x 10" x 12" (50 x 25 x 30 cm).

2-3 Specimens:

20-Gallon (74L) long glass vivaria – 30" x 12" x 12" (75 x 30 x 30 cm).

4-6 specimens:

40-Gallon (148L) breeder glass vivaria – 36" x 18" x 16" (90 x 45 x 40 cm).

I prefer to use standard plastic-framed lids with mesh-screen ventilation and two locking pegs for my Emperor vivaria. I replace the mesh screen with a sheet of Plexiglas (with numerous ventilation holes) to retain a higher humidity level.

As P. imperator is primarily found in hot humid climates throughout West Africa, a ventilated Plexiglas lid is useful in retaining a high degree of moisture and still allows a moderate rate of airflow in and out of the vivarium. A lid of this type is especially useful if your home is heated with a forced-air furnace which quickly decreases the air’s humidity. As with many tarantula species, high temperature/high humidity closed-environments with highly restricted airflow are stressful to specimens of P. imperator. In such stagnant environments, activity levels and feeding will decrease and the scorpion/s will confine themselves to their retreats or lay listless upon the substrate. Proper ventilation and airflow is important in maintaining these scorpions in an active and healthy condition. 

Before set-up, the vivarium should be cleaned with warm water and liquid dish-detergent to remove residue, dust, etc. from the interior and allowed to air dry. While the vivarium dries, mix 70% premium grade topsoil with 30% peat in a bucket. This substrate mix provides good moisture retention as well as assisting in retarding the decomposition of prey remains due to the acidic nature of the peat. As you blend the substrate materials together, add water until the substrate becomes moist.

Place a 4" (10 cm) layer of substrate in the vivarium and firmly pack it down, then add another 2" (5 cm) layer of loose substrate on top. As the majority of specimens are tireless burrowers, the firmly packed substrate will allow the scorpion/s to construct burrows through the substrate without the burrows collapsing upon them.

Retreat options are many including, slabs or tubes of cork bark, hollowed-out rotten tree limbs, sections of PVC pipe, supported stone slabs, etc. I prefer to use several sections of hollow, rotten tree limb and partially submerge them in the substrate. This not only creates a more naturalistic look to the vivarium, but also provides climbing surfaces for the scorpions and many small hiding areas for nymphs after they've achieved their second moult and have started developing their colouration. A flat piece of inverted cork bark on top of the substrate is also necessary to provide a firm, flat surface for the male scorpion to deposit his spermatophore when mating with the female.

Artificial or small living plants with low light requirements can be added to the vivarium for colour. Living plants are additional sources of humidity within the captive environment, but require additional care and maintenance that may be unappealing to enthusiasts that maintain moderate to large collections of arachnofauna. If living plants are used in the vivarium, leave them in their pots and use aquarium sealant to fix them to the bottom or wall of the vivarium to prevent your scorpion being injured if it burrows beneath the pot. The scorpion may unearth living plants that are planted directly in the substrate during burrow construction, but if living plants are desired, use a short section of cork-bark tube or PVC pipe to accommodate the roots. Embed the section of cork bark or PVC pipe into the substrate, add the plant and then add the substrate. This will protect the plant from the burrowing activity of the scorpions. Artificial plants should be fixed to the vivarium wall or bottom with aquarium sealant before adding the substrate. However, remember that Emperor scorpions can and do climb. In one vivarium, I had used a large piece of vertical cork bark against the rear wall to provide a climbing surface for two young males and to make the tank more aesthetically appealing. One day, I opened the lid to clean the vivarium and met a very startled male Emperor that was nestled snugly between the top of the cork bark and the vivarium lid!

After the interior of the vivarium is completed, a water dish must be added. It is important that the water bowl is not placed on top of the substrate as this could injure the scorpion if it burrows under it. I prefer to use an 8-oz. deli-container lid filled with substrate, inverted and fixed, bottom-to-bottom, to a 16-oz. clear deli-container with aquarium sealant. This makeshift water dish is roughly 6" high and extends from the vivarium floor to the substrate’s surface providing a secure and stable water dish for all burrowing species of scorpions.

Do not be surprised to find your Emperor submerged in its water bowl, as this behaviour is not uncommon. Make sure you also include a thin, flat rock in the water dish to facilitate easy exit for your scorpion and live prey. The longest period I've observed an Emperor scorpion remain submerged is a little over 32 minutes.

Another useful item is an adhesive strip-thermometer. Although the accuracy varies amongst manufacturers (typically ±2-3º), these inexpensive thermometers will allow you to have a general knowledge of the temperature within the vivarium. After the addition of the thermometer, water dish and a light misting with a water-spray bottle, place the lid on the vivarium and allow it to sit until the temperature and humidity have built up. Now it's time to acquire your scorpion.

Choosing a healthy specimen
As most pet stores discourage the handling of animals in their care, it is best to acquire your scorpions from a reputable dealer that has high-quality animals and can insure the sex of your specimen. Although there is no advantage/disadvantage in maintaining either sex, I have noted that wild-caught, young, male specimens (under 5" (12.5 cm)) tend to be more active and highly-strung than comparatively sized wild-caught females.

If you decide to acquire your Emperor from a pet store, look for a larger active specimen rich in colouration and robust in body size. Females are typically differentiated from the male specimens by their greater body width and thicker post-abdomens ("tail"). Do not choose specimens that appear lethargic or are actively moving about the vivarium with their chelae ("claws") held high over their bodies. Scorpions that carry their chelae in this position, ceaselessly moving about the vivarium, are rarely healthy and most die shortly after acquisition.

If you are acquiring specimens for a communal set-up, closely observe the behaviours of the scorpions in the pet store vivarium. Avoid acquiring specimens that appear to be "bullying" the other scorpions. Also, acquire specimens of similar size, as larger specimens tend to "bully" smaller members within the community. In communal set-ups, I prefer to introduce all members at the same time to allow them to acclimate to each others presence. Don't be surprised to discover that several specimens are sharing the same retreat. I have two mature females that have been living in the same section of hollow limb for over 1.5 years. 

However, if your goal is to breed your Emperor, then it is advisable to acquire a large, healthy, female specimen of 6"+ (15 cm) and allow her to construct a secure retreat. Feed and allow her to acclimatise to her new environment for 10-20 days before introducing the male.

Emperor scorpions should be maintained at temperatures of 80-90ºF (27-32ºC) with 80-90% relative humidity. Although Emperors can tolerate higher temperatures and humidity levels, with no apparent adverse effects, I have found no benefit in maintaining them at temperatures above 90ºF (32ºC). An occasional light misting of tepid water once a week will not only assist in keeping humidity levels elevated within the vivarium, but many Emperor scorpions actually appear to enjoy the occasional light misting.

Feeding and diet for Emperor scorpions is easy as most specimens are voracious and will readily accept offerings of insects, beef heart, anoles, house geckos, cockroaches, crayfish, shrimp, meal worms, earthworms, moths, butterflies, beetles, "pinkie" and "fuzzy" mice, etc. It is a rare Emperor that refuses a food offering! However, do not offer food for 5-7 days if your Emperor/s becomes so engorged as to make its movements cumbersome and slower than normal. A healthy Emperor scorpion should appear robust, but not bulbous and obese.

During crepuscular (dawn & dusk) and nocturnal (night) periods, Emperors will leave their retreats and actively explore their environment in search of prey and drinking water. Many will also choose these times to further excavate their burrows and interact with other members of the community.

In part II, courtship, mating and the rearing of young in captivity will be discussed as well as a look at how we in the hobby can contribute to the conservation of the Emperor scorpion in the wild.

References & suggested reading

Gaban, D. 1997: Gaban's Scorpion Tales: On Pandinus imperator (C.L. Koch) & Pandinus cavimanus (Pocock). Forum of the Amer. Tarantula Soc. 6 (3): 75-78.
Marshall, S.D. 1996: Tarantulas and Other Arachnids. Barron's Educational Series. Hauppauge, N.Y. (USA) p. 105.
Smith, A.M. 1998: The Gambia – Searching for Pandinus (Part I). J. Br. Tarantula Soc. 14 (1): 26-29.
Smith, A.M. 1999: The Gambia – Searching for
Pandinus (Part II). J. Br. Tarantula Soc. 14 (3): 83-86.
Smith, A.M. 1999: The Gambia – Searching for
Pandinus (Part III). J. Br. Tarantula Soc. 14
(4): 129-135.