Description & Natural History
Known as the Green Treefrog in Australia, one of its native countries, Litoria caerulea is known by a few other names elsewhere, including the Dumpy Treefrog and White's Treefrog. It was first described by English surgeon John White in 1790 (obviously not the well-known reptile and amphibian photographer whose photos feature in this article), who named it Rana caerulea, which means "blue frog". The specimen he described had been put in a preservative that had destroyed the frog's skin's layer of yellow pigment, giving it a blue appearance. It is interesting to note that some individuals of this species naturally lack some of this yellow pigment, giving them a bluish appearance as well.
|Family ||Hylidae (Treefrogs)|
|Subfamily||Pelodryadinae (Australasian Treefrogs)|
|Origin||Northeastern and eastern Australia and the island of New Guinea. Introduced to Florida, USA, and New Zealand|
|Adult Snout-to-Vent Length||Male: 76 mm (3 inches); Female: 102 mm (4 inches)|
|Life span||Up to 21 years (maybe more), 16 being average|
|Activity||Nocturnal, but can be active during the day, especially at feeding time|
|Temperature||Day: 29 °C (85 °F); Night: 20 - 24 °C (68 - 75 °F)|
|Food||Crickets, roaches, mealworms, waxworms, hornworms, superworms, pinkie mice, and so on. |
Litoria caerulea, White's Treefrog. This species can vary quite greatly in colour.
(Photo: John White)
White's treefrogs are one of the larger Hylid species in the world, growing from 76 mm to 102 mm (3 to 4 inches), depending on the gender of the frog. Unless a frog sings, lays eggs, or grows to about 100 mm (4 inches), the genders are nearly impossible to distinguish. They are stocky in build and some well-fed specimens will develop folds of skin, giving the impression of obesity. Toe and finger pads are well developed and quite adhesive, making it difficult to put the frog back down after you have picked it up, a trait common to many treefrogs. There is some webbing between the toes and fingers, which is more extensive between the toes than the fingers. The eyes have horizontal pupils, which are typical of the genus Litoria, as they are with most Hylids.
There is a thick fold of glandular skin called the supratympanic ridge, which is positioned above the tympanum or eardrum. Sometimes it can overgrow, almost covering the eyes. The skin on the dorsum is smooth, while it is granular on the flanks and venter (belly). As the Australian common name suggests, they are green dorsally, with some specimens having a blue tint. The green coloration can be from a dull green to a vivid green, or to even an olive or brown. The shade will often depend on the background on which one finds the frog; dark background, dark colored frog, and so on. Some individuals can have white spotting or flecking on their backs or sides - the third and the last photographs in this article show variations of frogs with this trait. Ventrally they are a white to creamy color, often with a pink tint. The inside surfaces of the legs can be dark purple to reddish brown in color. Waxy skin secretions, similar to that of frogs of the genus Phyllomedusa, help to prevent dehydration. And like these frogs, L. caerulea will smear these excretions all over itself to protect its delicate skin from the elements.
Throughout its considerable range, Litoria caerulea occupies many different types of habitat. It is abundant in the wetter coastal parts of its range, but can also be found around permanent sources of water in the drier parts of Australia. It can be also found around human habitation, most likely drawn by permanent water and insect prey.
The reasons for the popularity of White's treefrogs include their ease of maintenance, hardiness, and their calm disposition, which makes them more tolerant to handling than most frog species. A beginner can make a few more mistakes in the husbandry of this species, more so than he or she can make with more delicate types. In this author's opinion, the fact that they are adapted to a variety of ecosystems imparts this hardiness. It's because of this that I would suggest this frog is the definitive amphibian species for beginners, with, maybe, the tiger salamander coming in second place.
The two primary sources for White's in herpeculture outside of Australia are captive bred Australian stock and wild-caught specimens form the Indonesian province of Irian Jaya, which is the western half of New Guinea. Indonesian White's, as they're called, have a tendency to be much bigger than the captive bred Australians, as these frogs are caught as adults. Also Indonesian White's have a more pronounced supratympanic ridges than their Australian brethren. Australian specimens have a tendency to have better color than their Indonesian wild-caught counterparts, and are far more likely to be free of gastrointestinal parasites.
If your frog is wild-caught, it's a good idea to have a fecal exam done by a qualified veterinarian, and even if it's captive bred it never hurts to be sure. This will help in locating any protozoans or worms within your frog's digestive track. If found, or even just suspected, your frog could be treated with either metronidazole or fenbendazole, perhaps even both. Your vet can also check for and treat any other ailment he or she may find.
Quarantining any new animals is very good idea, even after it has been checked out by a vet. Not all diseases will be apparent and you need to keep new frogs away from your established animals for no less than thirty days, preferably in a completely different room. Any thing that quarantined animals come in contact with should be cleaned with a bleach and water solution, then thoroughly rinsed before they come in contact with any of your other animals. When handling new animals, the wearing of disposable surgical gloves is suggested. After use, discard them and never use them twice. These protocols should help prevent the spread of diseases, such as chytridiomycosis and "red-leg".
Litoria caerulea, White's Treefrog. Spotting and spot size is
unique to individual White's treefrogs and helps to distinguish
one from another. (Photo: Dr. Jean-Marc Hero)
Being larger than your average treefrog, White's treefrogs should be housed in larger enclosures. Adults should have a 20 US gallon tank or larger (~ 80 L). As with most treefrogs, ventilation is important, so a screen top should be used or the frogs should be housed in a mesh-covered cage. Make sure that whatever enclosure you decide to use is escape proof - you would not want your frog to escape, only to be found all dried up and dead a week or two later.
How you set up your frog's enclosure will depend on the level of maintenance to which you are committed versus the enclosure's aesthetics. If you want to keep the maintenance simple and the look of the enclosure really isn't a consideration for you, then white paper towels can be used as a substrate, a cat or dog bowl can provide water, and branches a place to climb on. If you want things to be a little more pleasing to the eye then you can replace the previous substrate with sphagnum moss and/or ground coconut shell, adding more cage furniture such as artificial or live plants to the mix. Either way, remember to provide regular maintenance and keep things clean and sanitary. Under no circumstances use gravel! If accidentally swallowed, it can cause gastrointestinal impaction, which left untreated, or even undiagnosed, can lead to death of your frog. Paper towels have a reputation for harboring more bacteria than an organic substrate so bear this in mind when drawing up a cleaning schedule.
A popular set-up would be the "natural" type. It's aesthetically pleasing, but involves more intensive maintenance (but likely less frequent) than the previously discussed setup. Spot cleanings will need to be done and after a while the whole set-up should be broken down and thoroughly cleaned, replacing substrate and washing cage furniture. No matter which setup you choose, monitor the conditions closely to safeguard your frog's health.
The best way to set up a "natural" terrarium is with a false bottom, which allows for water to drain off while keeping the substrate moist, but not soggy. To make one you will need a sheet of white egg-crate panel made for drop-ceilings, 3/4 inch PVC pipe, a 3/4 inch PVC cap, and needle point mesh to get started (if using metric measurements, piping appoximately 2 cm in diameter should be used). Start by cutting the egg-crate to the inside dimensions of your enclosure. Cut a hole in the egg-crate large enough for the PVC pipe to snugly pass through. Make this hole towards a back corner of the terrarium. The needlepoint mesh should be cut likewise. Next, cut the PVC pipe into six lengths of a 1/2 inch (1.3 cm) or so in length; these will serve as the supports for the false bottom. Next cut a length of the pipe to an inch (2.5 cm) shy of the height of the enclosure. So, if the tank is 10 inches (25 cm) tall, cut the pipe to nine inches (22.5 cm). This will be the drainpipe and it will be used to siphon off old, stale, or soiled water. For better flow when siphoning off water, make grooves or notches in the bottom of your drainpipe.
To put it all together, place the support pieces in the tank in an upright manner, then place the egg-crate on top of them, being careful not to knock the supports over. Next place the mesh over the egg crate. Insert the pipe into the hole you cut and place the PVC cap on the exposed end. This will prevent crickets and small frogs from climbing down and under the false bottom, where they will most likely die and foul the enclosure.
After constructing your false bottom, cover it with LECA (Light Expanded Clay Aggregate), followed by sphagnum moss. If LECA is unavailable to you, pea gravel can be used. Either way, make sure to rinse it well and that is thoroughly covered up by the sphagnum to avoid the risk of ingestion by your frog(s). I like to boil my sphagnum before using it, just to make sure it's safe (free of bacteria and parasites). If you do the same, make sure to drain off the excess water and to let it cool before using it. The enclosure can be decorated with live plants (that will grow in sphagnum), live moss and sterilized branches. Even though this type of enclosure maintains humidity fairly well, a water bowl should be provided.
Litoria caerulea, White's Treefrog. These frogs tolerate
holding well, but it's best to keep it to a minimum.
(Photo: Tammy Raabe Rao / rubicat.com)
A safe, simple substrate one can use is water. That's right, water! If kept in an aquarium, the bottom of the enclosure can be flooded with water about an inch or so deep (2.5 cm). Rocks and branches should be provided for resting areas for both the frog and its lunch, but watch out for drowned crickets. Feeding outside the enclosure in a Rubbermaid box, or similar, is recommended for this type of situation. Also, be very mindful of the water level - do not let it completely evaporate or you will have a large, ugly raisin instead of a frog.
A little bit more aesthetic version of this is a half-flooded tank. An aquarium/terrarium hybrid, if you will. Because of the larger volume of water involved, evaporation is more easily managed than in the previous setup. This is how I keep my White's, and they reside in a 30 US gallon aquarium (~ 120 L), filled half-way or so. Filtration is provided, as are artificial tree stumps on which the frogs can rest. There is a substrate of sand, which under normal circumstances would be a no-no, but this fine gravel is six to seven inches below the water's surface and is beyond the reach of the frogs' hungry mouths. Also, the frogs are not fed in their enclosure, so there is no chance of accidental ingestion of gravel/sand. As mentioned earlier, they are fed in a Rubbermaid box with drilled holes for ventilation. This allows them to eat and avoids the possibility of the crickets drowning.
In this kind of vivarium you can also keep fish because the frogs will not enter the water. If you do so, do not use wild-caught fish because they will certainly have parasites that could be passed to the frogs, and they may also carry communicable diseases.
Other cage furnishings include plastic plants that adhere to the tank walls above the water line by suction cups. These provide hiding places in which the frogs can seek refuge. As mentioned above there are two resin tree stumps that poke out of the water. These are sold in most pet stores these days and are found in either the reptile and/or aquarium sections. Avoid hollow ones, as they can be troublesome - with the hollow type, you run the risk of something crawling inside it and not being able to free itself, so why take the chance.
One of the plus sides of this type of setup is that maintenance is more straightforward. Every once in a while, the sides are scrubbed down, as are the plastic plants. The filter is cleaned and partial water changes are carried out, but never at the same time. To do so would destroy the established bacteria in the filter media, and these bacteria are necessary for biological filtration within the aquarium. Without biological filtration the aquarium would crash, potentially leading to toxic levels of ammonia and nitrite levels.
The pH of the water should be checked regularly. Overfeeding of the aquatic inhabitants can make the pH drop and a low pH would indicate that the tank is due for a partial water change. A pH around 6.8 is ideal, and at this level ammonia turns to ammonium, which is considerably less harmful to the occupants of the tank. However, a pH of 6.4 or lower can be harmful, especially under long-term conditions, so a water change should be performed at this level. Obviously your starting pH levels will vary depending on your water source, so ensure your water source's pH is compatible with aquatic animals before using it.
To perform water changes you will need a bucket and a siphon hose. I like the hoses with a cup or tube on the end, as they will suck debris out of your substrate very well, leaving the gravel behind. A 50% water change is normally enough to rectify a low pH, but be careful removing much more than that. Replacement water should be dechlorinated and it should be around the same temperature as the water removed. I find that it can be a good thing if the new water has a slightly higher pH - it can buffer the old water, hopefully putting the pH at around 6.8.
Litoria caerulea, White's Treefrog. Blue colouration
is rarely seen but particularly striking.
(Photo: John White)
White's treefrogs are not picky eaters. They will eat anything offered, provided that it moves, including other frogs (not recommended for hopefully obvious reasons). As with most frogs that are kept communally, try to keep frogs of similar sizes, lest the smaller frogs become part of the menu.
Usual prey items include crickets, mealworms, superworms, waxworms, hornworms, captive-cultured cockroaches, and the occasional pinkie mouse. Crickets generally form the bulk of the diet of most captive insectivores, but they are not nutritionally complete. So varying the selection of prey, along with the use of calcium/vitamin powder is important. Mealworms and superworms are actually the larvae of two different beetle species and as such they are high in chitin. Even though they are also high in calories, they should be used sparingly. Too much chitin in the digestion track can lead to bowel impaction. Waxworms are a caterpillar and are relatively high in fat content, so they too should only be used from time to time.
Tomato hornworms that are domestically raised are good to use. They are high in calories and grow fast. The down side is they grow fast, sometimes too fast. If you use them, you need to plan how you will use them, before they get to big. Always use domestically culture hornworms - the ones that you find feeding on your tomato plants are toxic from the food that they are eating. Cultured hornworms are fed a safe, non-toxic food, so they are safe to feed to your frogs.
A nice alternative to the cricket is the captive-cultured cockroach, which is becoming more and more available in herpeculture. They offer very good nutrition to your frogs, but beware - unlike crickets, many species of cockroach can climb glass. Keep this in mind when deciding on the cockroach species you are going to use.
Finally, the domestic mouse makes a nice treat once in a while, but use them sparingly because a regular diet of feeder mice can lead to health problems.
Do not overfeed your frogs. Too much food, plus a lack of exercise, will lead to obesity, health problems, and a shortened lifespan. So watch for signs of obesity, such as enlarged supratympanic ridges and lethargy.
Litoria caerulea, White's Treefrog. This is the position
assumed by most treefrogs at rest.
(Photo: Tammy Raabe Rao/rubicat.com)
White's treefrogs are great first frogs for someone who has never kept frogs before. Supposedly, they are a good first frog to breed as well, but I will not comment on this as I have never tried to breed them. I can tell you they are easy to keep as long as they are kept in a cage with good ventilation, are not overfed, have access to clean water, and are not overly handled. They do tolerate handling better than any other frog species, but don't over do it. When handling your White's or any other amphibian, it's a good idea to wet your hands. Also make sure your hands are free of chemicals found in soaps, perfumes, and colognes - these can be absorbed through the frog's skin and can affect its health, or even endanger its life. Remember, a frog is neither a toy, nor a puppy. Keep the periods of handling short, especially with a new frog. Let the frog warm up to you, and don't force it. Remember to keep its enclosure and water bowl clean. Do not let feces gather, as this will lead to a bloom in bacteria, which in turn can lead to red-leg, a very serious and highly contagious disease. Do not over feed and if you use mice pinkies, waxworms, mealworms or superworms as food, do so sparingly.
Misting your frog once a day is recommended. I do this at night just before I go to bed and I use distilled water for this, as it leaves no mineral deposits on the sides of the enclosure like tap water can. Water bowls, however, are filled with dechlorinated tap water, as distilled water lacks the salts and minerals found in natural water sources and this can put stress on the frog's permeable skin if it decides to get into the water.
If you take good care of your frog, it can live a long and happy life, potentially of 20 years or more.
1. Robinson, Martyn A Field Guide to Frogs of Australia - From Port Augusta to Fraser Island, including Tasmania 1993; Australian Museum/Reed New Holland Publications.
2. Coborn, John White's Tree Frogs 1994; TFH Publications.
3. Sihler, Amanda & Greg Poison Dart Frogs 2007; TFH Publications.
4. de Vosjoli, Philippe & Mailloux, Robert Care and Breeding of Popular Tree Frogs 1996; AVS Inc.
5. Merker, Gerold & Walter Feed Me! July 2008; Reptiles/Bowtie Publications.
6. Nabors, Patrick White's Treefrog (Litoria caerulea) November 2008; Reptiles/Bowtie Publications.
AmphibiaWeb Record: Litoria caerulea
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