Feeding Pet African Bullfrogs Pyxicephalus adspersus – Part 1

Hello, Frank Indiviglio here.

How does one satisfy a 9 pound amphibian!?”

Although African bullfrogs are among the most popular and long-lived (to 50 years) of amphibian pets, there remains some confusion as to their proper diet in captivity. Prompted by recent blog inquiries, I thought I’d set down a few thoughts on the subject.

Calcium Through Cannibalism
African bullfrogs, especially growing animals, seem to require a great deal of calcium. Perhaps this is due to their naturally fast growth rate – in their native southern Africa, breeding ponds dry quickly and tadpoles must transform quickly if they are to survive. The froglets then have but a short time to gorge upon enough food to sustain themselves through aestivation periods (dry weather dormancy) that may reach a year in length.

Often, the main source of food for the small metamorphs (transforming frogs) is other African bullfrogs. There is evidence that frogs will preferentially prey upon unrelated individuals, but in any case a diet so high in vertebrates is quite unusual for amphibians.

The Perils of a Rodent-Based Diet
Captive amphibians that are fed vertebrate-rich diets, usually in the form of mice, often develop eye (lipid deposits), kidney and liver problems. Although African bullfrogs do feed heavily upon other frogs in the wild, the practice of feeding captives largely upon mice, while a convenient way of sating these huge fellows, is not advisable.

Outside of the breeding season, the diet in the wild consists mainly of locusts, spiders, beetles, scorpions and other invertebrates…the vertebrates that are taken are more likely to be lizards, snakes and frogs than mammals. In some cases, rodent-based captive diets have not led to problems, but hair impactions and obesity-related health complications have resulted in others.

Providing a Healthful, Varied Diet

Fish and Crayfish
I prefer using goldfish, minnows and shiners for the vertebrate portion of African bullfrog diets, (the bones are an excellent calcium source), with only an occasional pink (un-furred mouse) being provided. Crayfishes, if available, are a fine food item and good calcium source. Neither of these food items is likely encountered by African bullfrogs in their native habitat – crayfish are not native to Africa, although 1 North American species is introduced, and the frogs tend to breed in fishless, temporary pools – but both have proven very useful in the long-term maintenance of this species.

Earthworms and Nightcrawlers
Earthworms, including nightcrawlers for adult frogs, are an excellent source of nutrition, and can comprise a majority of the food offered. The earthworm’s calcium: phosphorus ratio has been shown to generally hover around 2:1, which is ideal as regards frog diets. I believe that earthworms from different habitats may vary in this regard, but have none-the-less had very good results with earthworm-based diets over many years.

Commercially Available Insects
The balance of the diet can consist of crickets, roaches, super mealworms, waxworms, tomato hornworms and other commercially available insects. Large roaches (as well as nightcrawlers) present an excellent means of keeping your frog sated without resorting to rodents. For information on keeping and breeding the orange-spotted roach, please see my article “The Orange (or Guyana) Spotted Roach, Blaptica dubia.

Until then,

Frank Indiviglio

Read Feeding Pet African Bullfrogs Pyxicephalus adspersus – Part 2

Typical and Atypical Habitats of the Red-Eared Slider – Field Observations

Hello, Frank Indiviglio here.

I have run across colonies of feral sliders in Nassau (Bahamas), Baja California, Nevada, northern California, Japan (including in temple ponds in historic Kyoto!), Venezuela, St. Lucia and St. Croix.  Such sightings, of course, are not noteworthy, considering that this plucky survivor is well established in 25 or more countries on all continents except Antarctica (actually, when referring to animals with large ranges it’s standard to state “except Antarctica“…I’m not so sure this applies here for all I know there may be one paddling about some researcher’s outdoor hot tub!).  Parks in Korea, marshes in Brazil, ponds on Guam and countless other far-flung habitats all have their resident sliders.

It is, however, in New York where I have had most of my experience with feral populations.  Sliders, usually originating as released pets, are very common in waterways within NYC, but may also be found in relatively isolated areas as well.

Natural Habitat

Quiet, mud-bottomed waters with abundant vegetation and basking sites are considered to be the typical habitat in the northern part of the range, while tropical slider subspecies tend to occupy large rivers.  “Typical”, however, is a quite plastic concept as concerns this adaptable turtle. 

New York‘s Resident Sliders

In New York, I have encountered red-eared sliders such unlikely habitats as Pine Barren’s cranberry bogs with highly acidic waters, shaded, fast-moving streams and tidal creeks bordering the Great South Bay (please see photographs).  They are also to be found in the Hudson River along the west side of Manhattan, watering holes in outdoor exhibits at the Bronx Zoo and in just about every park pond within NYC…the various natural and artificial waterways of Central and Prospect Parks have amazingly dense populations. 

Along one stretch of the Bronx River which I have frequented since childhood, partially submerged shopping carts and car hoods are the most frequently used basking sites (the few logs that are available are rarely occupied by turtles!).

Further Reading

Detailed maps of the slider’s range in North America, as well as the US Geological Survey’s assessment of its impact on non-native habitats are posted at http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=1261

I’m very interested to hear about any sightings you may have had of introduced sliders, and will forward new records to the USGS…please write in.  Thanks, until next time, Frank Indiviglio.

Hands-On Experiences in Sea Turtle Conservation: Tagging Green, Leatherback and other Marine Turtles with the Caribbean Conservation Corporation in Costa Rica

Hello, Frank Indiviglio here.

Marine turtles (popularly known as “sea turtles”) are well-liked by all, herpers and “other” people alike.  They are, in many ways, creatures of great mystery, yet opportunities to become involved in hands-on research with them abound. 

My first field research outside of the USA was with green turtles (Chelonia midas) at Tortuguero, Costa Rica…a place I had been longing to visit since reading So Excellent a Fishe, written by legendary turtle biologist Archie Carr (if you are at all interested in sea turtles or the American tropics in general, please do not miss this book, there’s none other like it).

Archie Carr – the Visionary at Tortuguero

The Caribbean Conservation Corporation operates the world’s longest-running sea turtle monitoring program, and manages the now famous research station at Tortuguero.  It was the world’s only sea turtle protection organization when formed by Archie Carr in 1959, and remains the most influential. 

The CCC has always relied heavily upon volunteer researchers, and many who have roamed Tortuguero’s beaches have gone on to interesting careers in herpetology…certainly my own experiences there are still an influence after nearly 25 years.  The 5 decades’ worth of data gathered by program participants forms the foundation of nearly all that is currently known about the biology of sea turtles in the Caribbean. 

Volunteer Opportunities and Contributions

Leatherback Turtle and ICCC researchers become involved in all aspects of marine turtle field work – counting and re-locating eggs, monitoring nest success, and, most thrilling of all, tagging the huge females at night as they finish nesting (often carried out while mounted on the turtle as she scrambles for the sea!). 

Depending upon the season, participants may work with green turtles, 1,200 pound leatherbacks, or both.  Studies focusing on the area’s incredible diversity of birdlife (over 300 species have been recorded) are also conducted.  An amazing assortment of other wildlife, including jaguars, kinkajous, caiman, tarantulas of several varieties, jaguarundi, tapirs, and strawberry poison frogs, assures that you will be as awestruck as was I.

You can learn more at http://www.cccturtle.org/.  There are turtle tagging opportunities here in the USA as well… please look for future articles on diamondback terrapin tagging and other programs.

Please write in with your own herp conservation stories and ideas concerning other opportunities.  I’d be happy to provide further specifics and advice to anyone considering a turtle-tagging trip. Thanks, until next time, Frank Indiviglio.

Captive Care of the Ball or Royal Python, Python regius – Part 2

Click: Captive Care of the Ball or Royal Python, Python regius – Part 1, to read the first part of this article. Or, click:  The Natural History of the Ball Python, Python regius: Ball Pythons in the Wild to read about the natural history of Ball Pythons.


Most ball pythons take readily to pre-killed mice and small rats, with hatchlings usually being large enough to handle a “fuzzy” mouse.  In the wild, ball pythons do not feed when nighttime temperatures become cool (January-February in some areas), during much of the breeding season, and while incubating eggs.  They are well adapted to long fasts, and frequently go off-feed in captivity.  This can occur even in captive-hatched animals, tuned, perhaps, to an internally-controlled cycle, and is rarely a cause for concern. 

Individuals that go off feed regularly should be fed once weekly during those times when they do accept food, as should hatchlings and young animals.  Regularly-feeding adults do fine with a meal each 10-14 days.

Leaving a food animal in the terrarium overnight may induce reluctant feeders to eat.  Particularly stubborn animals may sometimes be tempted by switching food animal species…Mongolian gerbils are a particular favorite, but sometimes a weaning rat does the trick.   Of course, you may then be saddled with the responsibility of always providing that favored food item, so think carefully before offering anything too exotic.  “Scenting” a mouse by rubbing it with a with a favored food item is a well-known technique for tricking fussy snakes into eating.

Captive Longevity

A ball python kept at the Philadelphia zoo died at age 47.6 years, and holds, as far as I know, the longevity record for captive snakes.  Another was reported to have survived until age 51, but the record is unpublished.  A number of specimens have lived well into their 30’s.


Ball pythons are fairly mellow in disposition, but even long term captives will bite if provoked.  Their habit of coiling into a ball, while interesting, is a defense response – please do not harass yours into exhibiting this behavior.  As with all snakes, the head should not be placed in the vicinity of one’s face.


Only snakes in good body weight should be used for breeding purposes.  Success will be more likely if the male and female are housed separately outside of the breeding season. 

Ball pythons should be subjected to a semi-natural temperature and light cycle prior to and during the breeding season.  In October or November, nighttime temperatures should be allowed to fall to 68-72 F, and a night (dark) period of 12-14 hours should be established.  Daytime temperatures should remain as usual.  Feeding should be discontinued 1 month prior to turning down the temperatures, to allow for digestion of the last meal.

One month after the cooling period has begun, the female should be placed in the male’s cage for 1-3 day periods each week.  This process should continue for 6 weeks or so, after which temperatures and the day/night cycle should be returned to normal. 

Gravid females will usually not feed.  Eggs may be expected from 2 weeks to 2 months after the reintroductions have been discontinued, depending upon when copulation had occurred.

Incubation is fairly straightforward…I’ll cover it and related topics in the future.  Until then, please write in with your questions and comments. Thanks, Frank Indiviglio.

The Rosemond Gifford Zoo ball python information sheet is posted at:


Captive Care of the Ball or Royal Python, Python regius – Part 1

Hello, Frank Indiviglio here.

Please see The Natural History of the Ball Python: Pythons in the Wild, for information on the natural history of the ball python.


Ball pythons are now very well-established in the pet trade, and captive born animals are readily available.  They have much to recommend them as pets, including a mild disposition and manageable adult size.  Particularly unique is that they offer a “big constrictor feel” in a small package – thick bodied and muscular, ball pythons put one in mind of a much larger snake.

I heartily recommend this species for those interested in boas and pythons, but who lack the space required by larger snakes.  The very real safety issues involved in keeping giant constrictors are also not a factor with ball pythons, yet they display all of the behaviors exhibited by their larger relatives.

Ball pythons are available in an amazing array of color morphs and unusual patterns.

Captive Habitat

The Enclosure

Hatchlings may be started off in a 10 gallon aquarium and moved to a 20 long style aquarium as they increase in size.  Such might accommodate a small adult as well, but larger specimens do best in a 30-55 gallon aquarium.  Screen cover clips or metal cover screen locks are absolutely essential.

Heat, Humidity and Light

Ambient temperature should be maintained at 80-85 F, with a basking site of 90 F.  Temperatures can be reduced to 75-80 F at night. A ceramic heat emitter or under tank heat pad can be used to warm the air and create a basking site.  You can also use, in combination with these or solely (depending on terrarium size) an incandescent bulb.  The Coralife Reptile Spot Brightlight provides UVA and heat.  Ball pythons do not require UVB light, but may benefit from the provision of UVA. 

The R Zilla Nightlight Red Halogen bulb or other night viewing bulb will provide heat at night without disturbing your pet’s natural day/night cycle.  It will also enable you to view the snake’s nocturnal activities.  The ceramic heat emitters and under tank heaters mentioned earlier also provide heat without visible light.

A water bowl should be provided for drinking and soaking.  Fill it only to a level such that it will not overflow when the snake submerges its head or body.  The terrarium should be kept dry…moist conditions will lead to bacterial skin infections (“blister disease”).


R-Zilla Douglas Fir Bedding or Zoo Med Aspen Snake Bedding are good substrate choices.  Both allow for easy “spot cleaning”.  All substrate should be removed and the terrarium cleaned with R Zilla Terrarium Cleaner on a regular basis (i.e. once monthly).

Physical Environment – Habitat Type and Terrarium Decorations

Your ball python should be provided with a secure retreat….R Zilla Rock Dens and Hagen Hiding Caves are ideal.  A piece of freestanding driftwood will provide a rough surface upon which your snake can rub when in the process of shedding its skin.

If space permits, consider adding a log or piece of driftwood for your snake to climb upon.

Check out the second part of this article here.

Frank Indiviglio

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