Incredible Invertebrate
by Jonathan Rheins
January 31, 2012
Invertebrates—scorpions, centipedes and the like—are gaining popularity with herp enthusiasts and can represent a healthy segment of business for retailers.



I have been in countless reptile specialty stores in my many years as a herp enthusiast. In fact, I spend most of my waking hours working at one. Some have been quite impressive, while others left me wanting more. One thing that always stood out from store to store, however, was the assortment of giant, hairy spiders, centipedes and other creatures to which I had yet to become accustomed.

Why would a tarantula, scorpion or even a hermit crab be in a reptile shop? They certainly aren’t herps; in fact, they are about as distantly related as phyla come. However, they fulfill such a similar niche, both emotionally and in practice, for those animal lovers that desire something different.

As reptiles and amphibians continue to gain popularity in U.S. households as easy, quiet and simple pets, something new and different must present itself—and inverts are it. To be more specific, arthropods. With their chitinous exoskeleton and segmented bodies, these living fossils never cease to amaze. The boom I have witnessed in the popularity, availability, and husbandry knowledge of primarily terrestrial arthropods in just the past five or so years has been remarkable.


Tarantulas: The Hairy Beasts
Before becoming employed at a reptile specialty store that also happened to stock a wide variety of inverts, I had never considered owning or even handling a spider of any size or temperament. However, a few hundred pages of literature later, I became intrigued. From there, my interest in the biology, natural history and captive care of these understated animals has blossomed.

Tarantulas come in all sizes and colors, with demeanors ranging from easy going to down right nasty. Fortunately, the vast majority of species readily available in the pet trade are tractable, docile animals that rarely, if ever, show signs of aggression.

Among the most common species (and those that should be considered if a tarantula inventory is in your future) are the Chilean rose hair, Guyana pink toe, and any of the closely related Mexican species, such as the red knee and red rump. While the specific needs of each species will vary, there are some generalizations that can be made.

Generally, tarantulas require little space, often feeling more secure in a smaller environment than a vast habitat in which they may feel exposed or vulnerable. All of the aforementioned species can be comfortably housed in a five- to 10-gallon terrarium or similarly sized plastic critter cage. Most retailers already selling reptiles will likely have this type of enclosure in stock.

Additionally, temperatures for tarantulas are less exacting than those required for herps. In all but the harshest climates and coldest homes, many species will thrive at room temperature, assuming that the room is comfortable for human cohabitants. In some cases, the use of an under-tank heat pad (like those sold for reptile use) may be warranted to keep temperatures from falling much below 60 degrees for extended periods.

Tarantulas can be loosely grouped into two categories, terrestrial and arboreal. Amongst the terrestrial species, some will create a burrow from scratch, while others require a half-log hide of cork slab as a starting point. In all cases, tarantulas are notorious for making the habitat their own. They will excavate, move substrate and rocks, and reinforce it all with web until it is just right. For these animals, a deep layer of bedding (coco husk products, repti bark, sand, cypress mulch or a custom mix) and a small, shallow water dish is all that is necessary.

Arboreal species should be provided with similar substrate, plus a large, vertical slab of cork bark, lightweight wood or silk plants.

In addition to a shallow water bowl, lightly misting the enclosure with room temperature water a few times a week can help maintain adequate humidity levels for many tropical species.

Feeding is straightforward; these animals are carnivores, thriving on a staple diet of crickets, various types of mealworms, roaches and the occasional un-weaned mouse. Variety is key to long-term health, and no further supplementation to the food items is needed. However, the practice of gut loading—feeding prey a high-quality diet prior to offering them as the main course themselves—goes a long way toward providing a healthy diet.

Two or three appropriately sized prey items weekly are generally adequate. However, after a large meal or access to large amounts of food in a short time, some tarantulas will fast for extensive periods of time with no ill effects.


Scorpions: Lobsters of the Land
Scorpions, like tarantulas, come in all shapes and sizes, with some making better pets than others. While there have been no reported deaths from any tarantula bite, there are some scorpion species that are considered medically significant. In other words, a sting could mean a trip to the emergency room. For that reason, we will focus on the one species that is not only wildly popular, but also easy to keep, mild mannered and sold in numbers far beyond those of any others.

The African emperor scorpion is a large, bluish-black species from the tropical forests of West Africa. These scorpions are readily available, quite inexpensive and a perfect choice for the enthusiast ready to delve into the world of scorpions. These animals are more likely to pinch than attempt a sting and are easily handled by anyone with a gentle touch.

Emperor scorpions and many (but not all) other species can be maintained in quite the same manner as a terrestrial tarantula. Scorpions are more dependent on pre-existing burrows in which they will spend much of their time. Most scorpion species should be provided with multiple hides, a deep substrate appropriate for the species and a water source.

The feeding regimen for these animals is similar to that of the aforementioned tarantulas. Again, variety is paramount, and food should be offered once or twice a week. Any uneaten food should be removed from the habitat within 24 hours.


Centipedes & Millipedes: Legs Galore
These two commonly confused groups of inverts really have little in common—with the exception of lacking a spine, of course. Millipedes are placid, slow-moving creatures that eat vegetable matter and other decaying refuse on the forest floor. As pets, they thrive in a warm terrarium with adequate humidity, access to hides and a substrate suitable for burrowing. A diet of fresh, leafy vegetables, some fruit and a small piece of cuttle bone will keep millipedes happy and healthy. In lieu of cuttle bone, a small sprinkling of reptile calcium supplement may be added to the food once or twice a week.

Any millipede species found in the pet trade can be safely handled. Some may secrete an iodine-like liquid when startled, and while some find this substance slightly irritating to their skin, it can easily be rinsed off with soap and water.

Centipedes, however, are a notoriously aggressive group of critters than are best left to the experienced keeper. Like tarantulas, they are not lethal, but some large tropical varieties are capable of delivering an excruciating bite.
Husbandry of centipedes is straightforward. Provide access to clean water, a few varied meals every week and substrate, the consistency and depth of which should depend on the species’ natural habitat.


Jonathan Rheins is an avid herpetoculturist whose interest in all things reptilian began at an early age. He is a manager at LLLReptile & Supply Co. in Escondido, Calif., and when not fulfilling that position, spends his time working with and writing about a wide variety of exotic reptiles, amphibians and invertebrates.