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

See Feeding Pet African Bullfrogs Pyxicephalus adspersus – Part 1 for the first part of this article.

How does one satisfy a 9 pound amphibian!?

Wild-Caught Insects
Native invertebrates, collected from pesticide-free areas, should be offered whenever possible. In my work with frogs of all types, I’ve found very little that approaches the beneficial effects of a varied diet. Zoo Med’s Bug Napper is an excellent insect trap.

Sweeping a net through tall grass and searching around outdoor lights will also yield a number of useful species. Avoid using spiders, stinging and brightly-colored insects and fireflies, and do not collect during times when your collecting site is being sprayed with insecticides as part of mosquito control programs.

African bullfrogs under my care have enthusiastically accepted (“enthusiastically” goes without saying where these stout fellows are concerned!) cicadas, katydids, grasshoppers, beetles and their grubs, moths, tree crickets, hover flies, caterpillars, and most everything else I could come up with. I rely heavily upon wild-caught invertebrates throughout the spring, summer and early fall, but even a few beetles plucked from a screen door every night or so will go a long way in keeping your pet in the peak of health.

The Importance of Canned Insects
African bullfrogs can be easily trained to accept non-living food items from a plastic feeding tongs (well, to be honest, no actual “training” is involved…they generally just swallow whatever moves within range!). They have a very vigorous feeding response, and hit food quite hard. Accordingly, I avoid using metal feeding implements, as the risk of a mouth injury is fairly high.

This frog’s willingness to tong-feed is quite fortunate, because it enables us to use canned insects as a source of important dietary variety. The canned grasshoppers are quite large, and are suitable even for adult African bullfrogs. Large canned grasshoppers, silkworms and other insects can be broken into smaller pieces for juvenile frogs.

Meal Frequency and Nutritional Supplements
Juvenile frogs can be fed 3-4 times weekly, while adults do fine with a meal each 4-7 days (fast them for 10 days or so after a “heavy” meal of large shiners or pink mice). Smaller, more frequent meals can also be offered…I personally find this preferable, but it is not as critical for with this species as it seems to be for certain others.

The food of juveniles should be powdered with Reptocal at every other feeding, that of adults once weekly. During periods when you are unable to offer a varied diet, alternate Reptocal with Reptivite.

The African bullfrog pictured here may be seen in the wonderful amphibian exhibit area at Norwalk Connecticut’s Maritime Aquarium. I was involved in the project’s development as a consultant, and am pleased to say that the staff has done an excellent job of keeping and breeding a wide variety of amphibians in beautiful, naturalistic exhibits. The accompanying photographs show some of the aquarium’s other residents – albino American bullfrogs with pumpkinseed sunfishes, poison frogs and tiger salamanders. Also exhibited are barking treefrogs, Surinam toads, bronze frogs, mudpuppies, fire salamanders, red-eyed treefrogs and many other toads, salamanders and frogs from both the USA and abroad – please visit if you have the opportunity.

Further Reading
For a startling account of African bullfrog predation upon red spitting cobras and of the amazing degree of parental care these frogs provide to their tadpoles, please see my articles “An Appetite for Cobras” and “The African Bullfrog (South African Burrowing Frog, Giant Bullfrog), Pyxicephalus adspersus: The World’s Heaviest Frog is also a Devoted Parent”.

African bullfrogs seem to give rise to all sorts of interesting stories.

The African bullfrog is notorious for its immense appetite and willingness to take on quite formidable prey, including venomous snakes, scorpions and centipedes (please see my article “An Appetite for Cobras” for further details). At breeding time, however, males display a quite unexpected side – that of devoted, even “tender” parents.

Taking on all Foes – Lions Included!
Approaching 9 pounds in weight and 10″ in length, male African bullfrogs are the heaviest, if not longest (that title goes to West Africa’s goliath frog, Conraua goliath) of all Anurans. Bony projections (odontoid structures) that function as teeth line their lower jaws and fights for breeding rights sometimes result in fatalities.

Upon successfully breeding, however, the male African bullfrog turns his pugnacious nature towards defending his numerous eggs and tadpoles, and he is fearless in that task. I have seen footage of one leaping at the faces of African lions that had shown interest in his precious charges (the lions were only about 2 years old, but still not animals to be taken lightly!). Startled by the frog’s complete lack of respect for their size, the lions quickly moved off!

An Anuran Engineer
Perhaps even more surprising, the attentive males will, using the hardened tubercles on their hind feet, dig channels in the earth to lead tadpoles from drying to water-filled pools (or, perhaps, to direct water into the natal pool).

Parent Turned Predator
Once the tadpoles transform into small frogs, all bets are off and the male ravenously consumes all that he can catch. Other African bullfrogs may constitute the majority of the diet of newly transformed animals as well…breeding pools dry quickly in most habitats, and the frogs must gorge themselves before retreating underground for a dormancy period that may approach 1 year in length.

There is, however, evidence of kin recognition in African bullfrogs…so relatives may be spared (or at least only eaten as a last resort!), as is the case for the tiger salamander, Ambystoma tigrinum. In that species, cannibalistic larvae have been shown to preferentially prey upon non-related animals.

I’ll cover the captive husbandry of this unique heavyweight in the future.

You can read more about this frog’s natural history at:
http://research.amnh.org/herpetology/amphibia/index.php