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

Those who keep reptiles, especially turtles and lizards, are often of the opinion that amphibians make rather unresponsive pets.  True, a number of frogs and toads “come to life” at feeding time, but by and large amphibians are somewhat more retiring than are most reptiles.  This is especially true of the salamanders, many of which spend the vast majority of their lives in hiding.

A Beautifully-Colored and Responsive Salamander

The strikingly beautiful fire salamander is, however, a notable exception.  Native to cool, mossy woodlands in southwest Asia, much of Europe, and a small portion of northwestern Africa (a continent noted for its lack of salamanders), fire salamanders are as visually oriented as any turtle and eagerly anticipate regular feeding times.  Typically colored jet-black and mottled with bright orange or yellow, one subspecies, Salamandra salamandra fastuosa is largely bright yellow with bold black lines going down the body, legs, and tail (please see photo).

The many fire salamanders I have kept would, without exception, leave their retreats in anticipation of food when I approached their terrarium.  Most feed from the fingers or forceps and are not shy about moving about in broad daylight once they are acclimatized to captivity.  They even move differently than most salamanders – holding their bodies high off the group and “stomping about” in a very determined (and most “un-salamander-like”) manner. And, as you can see from the photo, their bold personalities also suit them well as “amphibian ambassadors” to budding herpetologists!

A Caution Concerning Temperature

Fire salamanders could very well be the ideal amphibian pet for reptile enthusiasts.  Their one drawback is a distinct sensitivity to warm temperatures…a cool basement or similar situation is pretty much a necessity for success with this species.  Although individuals hailing from certain populations are a bit more heat-tolerant than others, nearly all become stressed at temperatures over 72°F.

Breeding and Longevity in My Collection and Elsewhere

However, when properly cared for, fire salamanders are among the most long-lived of all amphibians, with the captive longevity record being just over 50 years.

I received the 2 individuals pictured together here as larvae 14 years ago – they have bred several times and show no signs of slowing down.  They do not lay eggs, but rather give birth to live larvae. Some populations, particularly those living at high elevations, give birth to fully formed little salamanders, skipping the larval stage completely.

How I Keep and Feed Fire Salamanders

I keep my fire salamanders in a basement where yearly temperatures range from 55-68F.

As you can see from the accompanying photo, they feed readily from plastic tongs.  This allows me to increase dietary variety through the use of canned invertebrates – snails are particularly favored.  Field research has shown land snails to be an important part of the natural diet in many regions, so I rely heavily upon these, especially during the winter when other foods are scarce.

I also use canned silkworms, live earthworms (50% of the diet), blackworms, crickets, mealworm beetles, waxworms, sow bugs and wild-caught insects (i.e. moths gathered with the aid of a Zoo Med Bug Napper).

Further Reading

You can learn more about this salamander’s natural history and the threats facing wild populations at http://amphibiaweb.org/cgi/amphib_query?where-genus=Salamandra&where-species=salamandra

The 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.

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.

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.

Read Feeding Pet African Bullfrogs Pyxicephalus adspersus – Part 2

Please see The Natural History of Axolotls and The Captive Care of Axolotls for further information on this fascinating captives.  Today I’ll finish up with a note on reproduction.

Inducing Reproduction

Adult axolotls are sexually dimorphic, with females being of a heavier build and having shorter and broader heads than males.  The cloaca of the male is noticeably swollen during the breeding season, and gravid females become very plump.

The natural change in day length and room temperature in temperate regions is often enough to stimulate reproduction.  Animals under my care in NY respond to natural variations in room temperature (they are housed in a cool basement) and possibly day-length (light enters through a ground level window).  Females generally lay from January through March, sometimes into April, at water temperatures of 55-60 F.

A sudden increase of water volume and a drop in water temperature seems to stimulate breeding even outside of the normal breeding season. Be careful, however, that females actually lay their eggs when artificial methods such as this are utilized. Retained eggs are a great concern among many captive amphibians, although I have not run into such with axolotls.

The Eggs

Please see the Natural History of Axolotls for details on courtship and mating.  Females have been observed to pick up several spermatophores during the night, although it is not clear all are from one or several males.  Eggs are attached to water plants or any other substrate within the tank. Plastic plants make ideal deposition sites (from a pet-keepers point of view!) as they are easily removed from the aquarium.

Axolotls are ravenous consumers of their own eggs, and few will survive if the adults are left in the same tank. At temperatures of 55 to 60°F, the eggs will hatch within two to three weeks. I generally provide them with mild aeration, just enough to keep the eggs slightly moving. Eggs deposited on plants and on floating objects seem to have a higher hatch rate than do those laid along the bottom of the aquarium, so be sure to provide suitable sites for your females.

Caring for Axolotl Larvae

The larvae lie motionless for a day or so after hatching, after which they become veritable eating machines.  They are best raised in a bare-bottomed plastic or glass aquarium.  Mild aeration via the return from a corner or sponge filter should be provided.  The young require daily feedings and very frequent water changes – after having raised 160 to adulthood at one point, I can vouch for this as being a labor-intensive but ultimately rewarding task.

I’ve found light plastic terrariums or sweater boxes that can be easily dumped and filled to be the method of choice when rearing large numbers of salamanders.  I’ve also used plastic wading pools, but unless you can arrange a way to drain and re-fill easily, these can be a bit un-wieldy to work with.  The extra room they provide does, however cut down on cannibalism.  Please see Captive Care of the Mexican Axolotl (Physical Environment, Feeding) for tips on setting up enclosures and feeding axolotl larvae.

The IUCN’s recommended conservation strategy for this species, as well as historical and natural history information, is posted at:

http://www.iucnredlist.org/details/1095