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

Note:  Please see Scorpions in Captivity – An Overview of Popular Species, Part I for general natural history and captive husbandry information.

Asian Forest Scorpions, Heterometrus spp.

Several species that superficially resemble emperor scorpions are sometimes available in the trade.  Known collectively as Asian forest scorpions and hailing from Southeast Asia, the most commonly seen is Heterometrus spinifer.  Like the emperor, it is jet black in color, but the claws have fewer spikes and its maximum size is 6 inches.

Basic Care

I keep Heterometrus in much the same way as I have described for emperor scorpions (Please see Scorpions in Captivity – An Overview of Popular Species: The Emperor Scorpion, Pandinus imperator).  Like their African cousins, Asian forest scorpions are also quite social…a group of 10 that I housed together in an exhibit at the Bronx Zoo co-existed for years without incident.  They seem to be quite temperature sensitive, and are best maintained at 78-85 F.  The gestation period is 5-8 months and sexual maturity is reached in 1-3 years.

Asian forest scorpions are somewhat more high-strung than emperors, and sting readily.  Heterometrus spinifer is not considered dangerous to healthy adults, but the closely related H. swammerdami of India (which, at 10-12 inches in length, is among the world’s longest scorpions) has reportedly caused fatalities.

Asian forest scorpions and emperor scorpions are both classified within the Family Scorpionidae.  Further information and a complete listing of all related species is available at http://www.ub.ntnu.no/scorpion-files/scorpionidae.php.

The basic care of this scorpion parallels that which I described for emperor scorpions in the article Scorpions in Captivity – An Overview of Popular Species; Part II: The Emperor Scorpion (Pandinus imperator). I’ll highlight species-specific information below.

South African Rock Scorpion, Hadogenes troglodytes

Ranging throughout much of southern Africa, this scorpion giant (7.5 to 8.5 inches in length) is always found in association with rocky places, especially the savannah-based outcroppings know as kopjes.  A thoroughly flattened body suits it especially well for climbing among and hiding within rock piles, a habitat it shares with the similarly-shaped flat rock lizards (Platysuarus spp.) and pancake tortoise (Malacochersus tornieri).

Color Variations

Rock scorpions vary greatly in color from population to population, and usually closely match the rocks of their habitat in hue.  Tan, reddish, brown, olive and yellow specimens, and a variety of shades in-between, all appear in the pet trade from time to time.

Captive Habitat

In captivity, they should be supplied with ample climbing opportunities in the form of rock piles and plastic reptile shelters   and caves.  If you use natural rocks, be sure to place the base of the pile directly upon the terrarium floor, not on sand, so that the scorpions do not burrow below and become crushed.  Repti sand makes a fine substrate.

The rock scorpion terrarium should be kept dry, with a light spraying of water once every 3-4 days being enough to supply their moisture requirements.  A water bowl is not necessary.

Rock scorpions are rather shy and high strung, much more so than their more commonly-kept relative, the emperor scorpion.  They will not thrive if forced to remain exposed.  Given secure shelters, however, they readily settle into captive life and may very well reproduce once habituated.  They are fairly slow-moving and seem to rely mainly upon their claws for defense.  Their venom is not considered to be dangerous to healthy adults.

An American Museum of Natural History field report detailing Hadogenes natural history and the description of 2 new species is posted at:

http://research.amnh.org/users/lorenzo/PDF/Prendini.2006.AMN.Hadogenes.pdf

Please see Part I and II of this article for information on scorpion natural history and further details on emperor scorpion care.

The captive reproduction of emperor scorpions is a most interesting endeavor (for hobbyists and, I imagine, the scorpions themselves!).  When properly housed and cared for, emperor scorpions are relatively easy to breed.  This is surprising, given that they are such unique and highly specialized creatures, and is an opportunity that should not be missed.  Many prominent invertebrate specialists started out with this species…keeping them is a wonderful way of becoming involved in invertebrate husbandry, and will almost certainly “hook” you for good.

Distinguishing the Sexes

In captivity, as within certain parts of the natural range, mating may occur during any month.  Adult females are longer and stouter than males, but this is not a reliable means of distinguishing the sexes.

There are some slight differences in the shape of the genital openings.  View the scorpions from below, in a clear plastic box, when attempting to sex in this manner – do not restrain them via hand or tongs.  Photos of the undersides of male and female emperor scorpions are posted at http://www.pandinusimperator.nl/EN/biology_EN.htm.

Courtship and Mating

Reproduction is most likely to occur if your scorpions are housed in a large terrarium that provides ample burrowing opportunities.  All species studied thus far perform a “mating dance”, with the pair locking claws and moving about.  It is theorized that this helps to clear a patch of ground for the deposition of the males’ sperm packet.  I imagine, but have not been able to determine for sure, that the specific dance “moves” also aid in species’ recognition among these nearly blind creatures (this is the case in “dancing” scorpion relatives, such as jumping spiders).

The male deposits a sperm packet on the ground and pulls the female over it (it is tempting here to draw analogies to salamander reproduction).  Hooks along the edges of the sperm packet latch onto the female’s genital opening, and the eggs are then fertilized internally.

Gestation and Birth

Gestation is highly variable, ranging from 7-10 months on average but sometimes exceeding 1 year.  It is likely that stress, temperature and other factors play a role in determining the length of the gestation period.

Females continue to feed while gravid, and may swell noticeably…when viewed from above, the carapace segments appear widely spaced, and seem ready to split apart (heavily-fed scorpions of either sex, however, may also appear gravid).

The young (sometimes called “scorplings”), 8-30 in number, are born alive and measure about 5/8 of an inch in length.  They are white in color and remain on the female’s back until their first moult, at which time they darken and begin to venture off on their own.  Once this occurs, they will readily accept ½ inch crickets, small waxworms, newly molted mealworms, wild-caught insects and canned silkworms.

Maternal Care of the Young

Female emperor scorpions feed their young with finely-shredded insects – this really is something to see.  By all means, try to do so by viewing yours at night with the aid of an incandescent “nocturnal” bulb.  The degree of care they provide to their young is extraordinary, and is far greater than one might expect from such supposedly “primitive” creatures.  Even among those scorpions that exhibit social behavior, emperors stand out as being very advanced in this regard.

Caring for the Mother and Her Brood

Once the female has given birth, all other scorpions should be removed from the terrarium, as she will become highly aggressive and defensive.  Do not relocate the mother…this inevitably stresses her and may cause her to consume her young.

Females with young react aggressively to any disturbance, even occasionally grabbing and eating scorplings that become dislodged from their backs.  This is not an uncommon occurrence – do not remove the remaining young unless she begins eating them regularly, as the overall survival rate is improved when clutches are reared with their mother.  I have raised several clutches to adulthood with the mother present – the key lies in disturbing her as little as possible and in providing a deep, secure burrow.

I usually raise the terrarium’s temperature to 85-90 F when rearing young emperor scorpions – this may not be essential, but I have found it to work well.

Sexual maturity in the wild is reportedly reached in 4-7 years, but captives may breed when only 12-14 months of age.  Emperor scorpions under my care have reproduced at age 3 and 4 years.

The Woodland Park Zoo provides interesting information on emperor and other scorpions in nature and captivity at:

http://www.zoo.org/factsheets/scorpion/scorpion.html

Click: Emperor Scorpion, Pandinus imperator, Care – Part 1, to read the first part of this article.

Heat, Humidity and Light

Temperature should be maintained at 78-86 F, and humidity at 70-85%.  Do not cover the terrarium’s top with plastic in order to increase humidity, as air circulation is desirable.  Rather, use a moisture-retaining substrate (please see above) and spray frequently with de-chlorinated water (the substrate should be slightly moist to the touch).

In order not to disturb your scorpions at night, heat should be provided by an incandescent “nocturnal” bulb; this will also allow you to observe your pets when they are most active.  A ceramic heater may also be used.

Due to peculiarities in molecular structure of the exoskeleton, scorpions fluoresce under UVB light.  Despite having discovered this in the 1940’s, scientists cannot as yet determine why such a facility should exist. The fluorescent sheen they exhibit is quite unearthly…a UVB-lit scorpion exhibit that I maintained at the Bronx Zoo has long been a favorite of visitors.  Try lighting your scorpions with a UVB bulb at night…and while you’re at it, please see if you can find out what is going on with their fluorescence!

Feeding

Scorpions should be offered a wide range of soft-bodied invertebrates, including crickets, roaches, waxworms, silkworms and butterworms; some individuals will accept earthworms as well.  Do not rely on crickets as a dietary mainstay; rather, provide as much variety as possible.  In the warmer months, I feed mine mainly on wild caught moths, earwigs, caterpillars, katydids, crickets and soft-bodied beetles (Zoo Med’s Bug Napper is an excellent insect trap).

Emperor scorpions take readily to tong feeding , and should be provided with canned grasshoppers and silkworms as a means of increasing dietary variety.  We know nothing of their vitamin/mineral needs…I powder my scorpions’ food once weekly with a reptile dietary supplement  as “insurance”.

Emperor scorpions may on occasion take small frogs, lizards and even nestling rodents in the wild.  This is almost certainly a rare event…vertebrate food is not required in captivity.

Water should be provided in a shallow, easily-exited water bowl.

Social Grouping/Compatible Species

Emperor scorpions present the opportunity for fascinating studies in the evolution of social behavior.  Despite being as close to “living dinosaurs” as we are likely to see, these ancient animals exhibit complex social behaviors.  In the wild, they often live in discreet groups that occupy a single, extensive system of burrows.  We know little about the functioning of these groups.  The young of emperor and other highly social scorpions remain dependent upon their mothers for longer than do other species, but other than that, specific details are lacking.

As emperor scorpions readily exhibit natural behaviors when properly housed in captivity, the research potential for interested hobbyists is enormous.  I urge you to seriously consider working with this fascinating creature.

Captive groups almost always co-exist peaceably, provided they are given ample space and hiding/burrowing areas.  Females that breed in group situations require special attention…I’ll address this in an article on reproduction shortly.  Emperor scorpions will attack and/or consume other types of scorpions.

Further information and references to papers on emperor scorpions is posted at

http://www.ub.ntnu.no/scorpion-files/p_imperator.php

One of the world’s largest scorpions, the emperor is also the most widely kept, and captive born specimens are readily available.  Other than females with young on their back, emperor scorpions are rather mild-mannered.  The sting may be painful, but is not considered dangerous to healthy adults.

Physical Description

Females may reach 7 inches in length and, when gravid, exceed 50 grams in weight (by way of comparison, the average house mouse weighs 20 grams); males are slightly smaller.  Both sexes are jet black in color.

Range and Habitat

Emperor scorpions thrive in areas of high humidity, and are generally associated with rainforests.  There are some reports of populations living in wet savannas and human-influenced habitats as well.  They are native to northwest and north-central Africa, with their range extending from Mauritania south and east to Zaire.

Status in the Wild

Wild populations have been little-studied, but concern over huge exports in the early 1990’s led to the listing of this species on CITES II.  Those in the US trade are largely captive bred, although animals “ranched” in Togo and Benin are sometimes imported.  The closely related P. dictator and P. gambiensis, uncommon in the pet trade, are also listed on CITES II.

CAPTIVE HUSBANDRY

The Enclosure

Provide your scorpions with as much space as possible.  A pair can be kept in a 10 gallon aquarium, but larger is always better; a 20 gallon can support 4-6 animals.  The screen cover should be secured with cage clamps.

Physical Environment – Habitat Type and Terrarium Decorations

Emperor scorpions inhabit extensive burrow systems in the wild, and should be given the opportunity to burrow in captivity.  Under such conditions, they will exhibit a wide range of interesting behaviors – far more so than if kept in a simple terrarium.  When able to construct secure burrows, captive scorpions become quite confident and therefore more likely to show themselves.

Emperors also take readily to artificial caves  and hideouts excavated below driftwood and other structures.  I once created a very interesting exhibit by partially burying a number of artificial caves at different levels within the substrate of a 55 gallon aquarium.  The resident colony of emperor scorpions dug pathways between the various cave entrances and established a complicated maze of “avenues” – more reminiscent of rodent runways than anything one might associate with an invertebrate.  I highly recommend this type of set up for your scorpions.

Substrate

Excavator Clay Burrowing Substrate  is specifically designed for fossorial animals and is a great choice for burrowing scorpions.   A few handfuls of Jungle Earth Reptile Bedding  should be mixed in to help retain moisture.

Click: Emperor Scorpion, Pandinus imperator, Care – Part 2, to read the second part of this article.