Pyxicephalus Adspersus.
Pyxicephalus Adspersus.

Pyxicephalus

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Pyxicephalus frogs, also known as African bullfrogs, or in the pet trade Pyxie frogs, are highly predatory frogs from Sub-Saharan Africa.

Pyxicephalus Adspersus.

A giant African bullfrog (Pyxicephalus Adspersus) kept as a pet.

Taxonomists sometimes debate which varieties are to be recognized as separate species, but usually three or four species are recognized. Most people agree that at least the edible bullfrog (Pyxicephalus Edulis), the giant African bullfrog (Pyxicephalus Adspersus), and the Calabresi’s bullfrog (Pyxicephalus Obbianus) are distrinct species.

Pyxicephalus Edulis

An edible bullfrog or dwarf African bullfrog (Pyxicephalus Edulis).

All African bullfrogs are eaten by humans in their native countries, not just the edible bullfrog. In fact the giant African bullfrog probably provides a much more satisfying meal since it is so huge.

In the pet trade Pyxicephalus Edulis is usually known as the dwarf African Bullfrog or dwarf Pyxie frog, and Pyxicephalus Adspersus is known as the giant African bullfrog or giant Pyxie frog. I am not aware of any specific trade name for Pyxicephalus Obbianus but it is also sometimes kept as a pet, the owner perhaps is often unaware that it is not one of the other species. (a Pyxicephalus Obbianus has the coloration of a Pyxicephalus Edulis but it is only slightly smaller than a Pyxicephalus Adspersus).

The two sexes show significant size difference, but unlike most other frogs, male Pyxicephalus frogs are significantly bigger than the females. The male giant African bullfrog is around 9 inches snout to vent which makes it the second longest frog in the world after the Goliath frog). With over 4 pounds of body weight the male giant African bullfrog is the bulkiest and heaviest of all frogs. A female African bullfrog is about half the length of a male of the same species.

Most description that can be found on-line relate to Pyxicephalus Adspersus, but the other species are similar in many respect.

African Bullfrogs in the Wild

Pyxicephalus frogs live in environments that look inhospitable for frogs. Their native range is baked under the African sun, often drying out for several month if not over a year making it impossible for frogs to live there. African bullfrogs survive by making a cocoon out of their shed skin that is reasonably water tight and protects the frog from drying out while aestivating inside its cocoon. A coping mechanism similar to what South American horned frogs use to survive in their environment.

Pyxicephalus Adspersus shedding and eating its skin.

Like all frogs, African bullfrogs regularly shed their skin even under normal circumstances. When they don’t need the skin as a survival suit frogs just eat it. This frog is sitting in a comfortable terrarium and it is in the process of eating its own skin.

After the rains start to fall African bullfrogs emerge from their dormant state and the males start to fight with each other for the right to become the father of the next generation. This can be one explanation for the much bigger size of the male African bullfrog — like in the case of elephant seals sexual selection might be at work since larger males have much more offspring than smaller ones.

The much smaller female African bullfrogs in turn line up to spawn with the victor, thus the dominant male becomes the father of most of the tadpoles in the small pool of water where they spawn.

African bullfrogs tend to spawn in ephemeral pools so that their offspring can avoid predators living in more permanent bodies of water. After fathering most of the tadpoles in the pond the dominant male African bullfrog has a vested interest in the welfare of those thousands of tadpoles, and he takes his fatherly duties very seriously guarding the tadpoles and attacking animals much larger than himself if they come close.

This once again favours larger males with larger fangs — a much bulkier frog with a more vicious bite is obviously more efficient in convincing would be predators that they do not want bullfrog tadpoles for dinner after all.

He also herds the tadpoles around seeking appropriate water conditions based on temperature and other factors such as water oxygenation. When the spawning pool eventually starts to dry out it is his duty to dig a tunnel to a some much bigger pond so the tadpoles can move to a more permanent body of water to finish their development and metamorphose into froglets.

An African bullfrog will usually eat any animal that fits into its mouth, which in the case of a male giant African bullfrog is quite large. They have been known to swallow an adult rat whole, but mice, lizards, snakes, birds, fish, various insects all get gobbled up if they come too close, as well as other frogs including those of the same species. There are even stories on the Internet of a giant African bullfrog dining on baby cobras in a zoo.

Like many large predatory frogs, African bullfrogs are cannibalistic although adults tend not to eat each other in the same almost compulsory manner as horned frogs do.

African Bullfrogs as Pets

Pyxicephalus frogs, in particular the giant Pyxie frog (Pyxicephalus Adspersus) are popular pets and they are even bred in captivity for the pet trade. If you are into frogs a Pyxie frog is an awesome animal to have.

In captivity it is usually possible, although not necessarily recommended, to house multiple adult Pyxie frogs of the same size together — unlike Pacman frogs who would almost inevitably try to swallow one another, even if it leads to the suffocation of the attacker and the death of both animals.

Baby Pyxicephalus frogs, right after metamorphosis, on the other hand need all the nutrition they can get before conditions force them into aestivation so they will gobble each other up if they get a chance. It is unsafe to try to keep very young Pyxicephalus frogs together in captivity as most of them probably will end up eaten by their peers.

Baby Pyxicephalus Adspersus.

A baby Pyxicephalus Adspersus — a really cute little frog.
Baby giant African bullfrogs have an interesting camouflage pattern coloration but in adults it fades and really old males have an almost uniformly green back. The three bright green stripes on the back can be used to distinguish young individuals from Pyxicephalus Edulis as the latter has a tan colored stripe running down in the middle of its back.

African bullfrogs are popular pets because they are easy to care for, hardy, and long lived. In spite of being basically wild animals African bullfrogs do adapt well to life as a pet. In captivity where they have access to safe food, are protected from predators, and receive medical care giant Pyxie frogs can live for decades, over 40 years old specimens are not unusual. There is also the coolness factor of owning a 4 pound frog that can swallow rats whole or eat poisonous snakes for breakfast.

In spite of their size, their need for space is modest since they tend to sit in one place and don’t require a lot of room to run around.

Pyxie frogs can survive a wide range of temperatures although they prefer something in the vicinity of 80 degrees Fahrenheit. They will eat a wide variety of live prey items and tolerate various terrarium conditions, thus they are relatively undemanding pets.

Pyxicephalus Adspersus.

People tend to get attached to them as pets, especially if raised from a tiny baby into adulthood. It seems that we humans are good at reading the body language of African bullfrogs. So even though one should avoid handling a pet frog as much as possible, still there is a sense of interaction with your pet.

One must trade carefully when dealing with African bullfrogs as they have large and sharp odontoids in their mouths — the sensation of being bitten by a Pyxie frog is often described as similar to having your hand stuck between pieces of broken glass.

Pyxicephalus Adspersus Odontoids.

A young Pyxicephalus Adspersus shedding and eating its skin.
Observe the odontoids — in older male giant African bullfrogs these can grow to more significant size and deliver a nasty bite.

It is never a good idea to wave one’s fingers in front of the mouth of an African bullfrog. Whatever you do, do not hand feed your pet Pyxie frog. Frogs tend to attack whatever moves in front of them and they might not be able to tell your hand from the food you are offering.

Care also must be exercised when cleaning the frog’s enclosure. If you must handle the frog, e.g. to remove it from its cage when it becomes necessary, grab the frog from behind just under the front legs and handle it gently but firmly.

Both you and the frog can get hurt if you let it bite you. African bullfrog bites can be serious and they can land someone especially unlucky in the ER for stitches. On the other hand getting the frog to release something that is already in its mouth can be a lengthy procedure that unduly stresses the animal — and that is if one even has the discipline not to panic and do something stupid. Various authors recommend all sorts of methods including holding the frog under running cold water as well as using various objects such as kitchen utensils or credit cards to try to pry the frog’s mouth open.

Best to avoid being bitten altogether and just handle the animal firmly when you have to handle it — and try to avoid handling it as much as possible, frogs generally don’t like to be touched.

You can interact with your pet Pyxie frog, but you should realize that fogs do not like to be petted, and you can’t play fetch with it either like you would with your dog.

Interaction really should be mostly limited to activities related to feeding the frog. African bullfrogs show interest in what is going on around them and will even actively chase prey. Just try throwing insects in front of your Pyxie frog — preferably with feeding tongs, you do not want to get your hand accidentally mistaken for food — and watch how the frog catches them. This can be quite entertaining and your frog will be happy about it.

Online care sheets for Pyxie frogs are often just Pacman frog care sheets with the word Pacman replaced by Pyxie or some such. This is not right. While Pyxie frogs are adaptable creatures and can survive if kept like a Pacman frog it does not mean that is their preferred way of living.

Some Pacman frog species live far from open bodies of water, in forests and meadows and such, and only go into the water to breed, they also tend to hunt for larger prey, often for other frogs and will not even bother going after very small insects. African bullfrogs on the other hand enjoy being in water if they have access to it, and they will spend much of their time in their water bowl or the water area of their terrarium.

African bullfrogs also have more insectivorous habits and they will go after really small insects especially if those are right in front of them and can be just licked up. African bullfrogs have a very good aim with their tongues at short range — although not nearly as good as some toads — and they are capable of picking up even a fly or a small worm from the tip of the feeding tongs. That is not something that Pacman frogs would probably ever do, they would rather launch themselves with the force of a freight train and try to swallow the feeding tongs.

I just can’t picture a Pacman frog playing a video game on a cellphone the way a Pyxie frog plays Ant Smasher on a popular YouTube video.

Contrary to the popular belief African bullfrogs aren’t mindless eating machines and they have relatively good table manners for a frog.

Pyxicephalus Adspersus eating an Earthworm.

Pyxicephalus Adspersus eating an earthworm.

Further Readings:

Pyxicephalus Adspersus.
Last updated: March 13, 2016

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