Keeping the African Bullfrog, Pyxicephalus adspersus: the Importance of Cleanliness in Assuring a Long Life for Your Pet

Hello, Frank Indiviglio here.

African BullfrogThe robust African bullfrog shares with the fire salamander and Chinese/Japanese giant salamanders the distinction of being the longest lived of all captive amphibians. I personally know of 2 specimens that lived for 21 years in captivity, both owned by the same person (interestingly, although housed separately, they died within a few days of one other). The unpublished longevity record for the species is 50 years.

Ammonia – an Ever-Present Threat
However, one easily-overlooked point – terrarium hygiene – can very quickly end their potentially long lives. In my experience, a lack of attention to this critical point is the most common cause of African bullfrog deaths in captivity. Despite their burly, somewhat tank-like exteriors, African bullfrogs are extremely sensitive to ammonia toxicity…tiny metamorphs and huge, decades-old adults are equally vulnerable.

These frogs usually (but absolutely not “always”!) defecate in their water bowl. The bowl should be cleaned at least once daily, even if it does not appear fouled. Frogs soaking in fouled water will absorb ammonia through their skin and can die in short order.

Daily care while you are on vacation or otherwise absent from home is a must…a day or so of missed cleanings can easily kill a treasured old pet (think of how you’d feel then!).

Useful Products and Techniques
R-Zilla Terrarium Cleaner is safe to use on water bowls and terrariums, but wherever amphibians are concerned it is essential that all surfaces are rinsed thoroughly after being disinfected. Be sure to use a water conditioner  to de-chlorinate water used in the bowl and in spraying the substrate.

A very useful product of which I was made aware recently is Hagen Cycle. It is contains huge populations of live beneficial aerobic bacteria, is being increasingly used in laboratory frog colonies, both for aquatic species and in the water bowls of others. I believe it is an important product to consider when keeping large frogs, which produce copious amounts of nitrogenous wastes (it is not, however, a substitute for water changes).

As your frog may also defecate outside of the water bowl, it is important that the entire terrarium can be easily cleaned. Simple set-ups are therefore preferable for African bullfrogs (when designing planted zoo exhibits, I always allow for a floor drain and false bottom, so that the substrate can be hosed down without removing the frog). Washable terrarium liners are very useful in African bullfrog enclosures.

Further Reading
You can read more about African bullfrog natural history and captive husbandry in the following articles on this blog: The African Bullfrog – Devoted Parent, An Appetite for Cobras , and Feeding African Bullfrogs.

Please write in with your questions and comments. Thanks, until next time, Frank Indiviglio.

The Cuatro Cienegas Slider (Trachemys scripta taylori) and other Unusual Relatives of the Red Eared Slider (Trachemys scripta elegans)

Hello, Frank Indiviglio here.

Note: For further information on red eared sliders in the wild and captivity, please see The Red Eared Slider in Outdoor Ponds  and Typical and Atypical Habitats of the Red Eared Slider

The red eared slider is familiar to herp enthusiasts the world over, but many of its relatives are not.  As one of the many subspecies of the common slider, the red-ear is cousin to a surprising variety of rare and poorly studied turtles.

Widely-ranging Subspecies

The red-eared slider is one of 15 described subspecies of the common slider, Trachemys scripta.  The common slider is considered to be the most variable, in terms of physical appearance, of all turtles, and has a huge natural range.  Common sliders of one variety or another may be found from southeastern Virginia to northern Florida, west to Kansas and New Mexico and south through Mexico to northern Columbia and Venezuela.

A Slider among Sea Turtles

The most “exotic” slider subspecies that I have handled are the Nicaraguan slider, Trachemys s. emolli, which was shown to me by a friend in Costa Rica, and the Meso-American slider, Trachemys s. venusta.  I encountered the Meso-American slider at Tortuguero, Costa Rica, where it nests on ocean beaches amidst green and leatherback turtles. 

It is said that Meso-American sliders wash out to the sea from the mouths of nearby rivers, then make their way to the beaches to nest…but I have not heard an explanation of  how they negotiate the return trip.  In any event, I have observed them in large rivers and can attest to the fact that at least some individuals nest on ocean beaches, right along with sea turtles.

Sliders in the Desert and Box Turtles in Water

Perhaps the rarest of all slider subspecies is the Cuatro Cienegas slider, Trachemys s. taylori, found only in the Cuatro Cienegas Basin of Coahuila, Mexico.  Smack in the middle of the Chihuahuan Desert, this 500 square mile oasis is also home to another very rare and unusual turtle – Coahuilan box turtle, Terrapene coahuila.  Long isolated from related species, the 75+ animal species endemic to Cuatro Cienegas have developed a host of unusual survival strategies.  The Coahuilan box turtle, for example, is unique among all box turtles in spending most of its life in water.

I’ve worked with Coahuilan box turtles in captivity…its hard to describe how strange it is to see them bobbing about in deep water.  With their highly-domed shells, they seem completely unsuited for a watery existence, yet get along quite well.  Their future in the wild is tenuous at best, but they breed very well in captivity.

Further Reading

An interesting article on the unique reptiles and amphibians of the Cuatro Cienegas Basin is posted at


Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Emperor Scorpion, Pandinus imperator, Care – Part 2

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!


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.

I’ll cover emperor scorpion breeding and the care of other scorpion species next time.  Until then, please write in with your questions and comments.  Thanks, Frank Indiviglio.

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

Emperor Scorpion, Pandinus imperator, Care – Part 1

Hello, Frank Indiviglio here. Please see Scorpions in Captivity – An Overview of Popular Species for information on scorpion venom and natural history.
Emperor Scorpion, Pandinus imperator

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.


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 – please write in if you’d like more specific information.


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.


Frank Indiviglio

Cannibalism and Carrion-Feeding in Rattlesnakes (Genus Crotalus) and Water Moccasins (Agkistrodon piscivorus) – Research Update

Hello, Frank Indiviglio here.

Writing in the current issue of the journal Animal Behavior, researchers from the University of Grenada report that female Mexican lance-headed rattlesnakes frequently consume infertile eggs and non-living young after giving birth.  This is said to be the first documented case of cannibalism among rattlesnakes (please see below for my observations, however).  Interestingly, with a sole exception, the females did not consume young that were born alive, even though these remain inactive for several hours after birth, and appear (to us, at least!) to be dead.

Rattlesnakes bear live young, and females use up a great deal of energy and body mass during gestation (they do not feed while gravid).  It is theorized that consuming those young which are dead upon birth helps them to recover their strength.

Rattlesnake Cannibalism in another Species

While working with the comprehensive rattlesnake collection at NYC’s Staten Island Zoo, I had the opportunity to participate in breeding efforts for a number of species.  Most births occurred at night and were not filmed, so I cannot say if females of other species ever consumed non-living young.  However, newly born Neo-tropical rattlesnakes (Crotalus durissus) did consume litter-mates on two occasions.

Hog Fat and other Unusual Snake Foods

Contrary to popular belief, many snakes consume non-living prey (i.e. carrion) in the wild.  The most unusual incident I recall was a note published in the journal Herpetologica…a water moccasin (Agkistrodon piscivorous) was observed stripping fat from a road-killed feral hog! 

Of the snakes I have worked with in the field and captivity, moccasins, indigo snakes, black racers and anacondas stand out as taking the widest variety of prey species, and each engages in cannibalism.  One particularly large moccasin I cared for consumed a northern water snake that shared its exhibit (not my idea – I had moved on by then!!).  I’m sure the same occurs in the wild, in areas where moccasins and various water snakes co-exist.

A Collection for Rattlesnake Aficionados

I had the wonderful opportunity of participating in the renovation of the Staten Island Zoo’s reptile house, former stomping ground of legendary snakeman Carl Kauffeld (known to all snake keepers as the author of Snakes, the Keeper and the Kept and Snakes and Snake Hunting). 

As in former times, the zoo now boasts an impressive rattlesnake collection…please visit if you have the opportunity.  Pictured here are a few exhibits that I set up for the opening – Neo-tropical rattlesnakes, banded rock rattlesnakes and desert Massasaugas.

Further Reading

Lance-headed rattlesnake photos and natural history information are posted at:


Please write in with your comments and questions.  Thanks, until next time, Frank Indiviglio.

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