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

Those who keep or observe frogs soon learn of their prodigious appetites. Surely the champion Anuran eater must be the African bullfrog, Pyxicephalus adspersus. Native to southern Africa, this brute is a popular pet, and with good reason – captive longevity is said to approach 50 years. Two animals that I know of, kept in separate enclosures by the same person, both expired at age 21, in the same week.

The most memorable “frog-eating footage” I’ve seen focused on African bullfrogs in the Etosha Pan, northern Namibia. One enormous animal swallowed a centipede of at least 10 inches in length, which bit the frog numerous times on the way down. Another frog latched onto an emperor scorpion, which also did its best to make itself a “memorable” meal. But a note I read in an African nature journal tops all – a huge male frog burrowed into an outdoor cage at a South African snake park and was, when discovered, in the process of swallowing his 17th baby spitting cobra!

All of this eating results, as you might imagine, in frogs of impressive proportions – a male at the Fort Worth Zoo measured 10 inches from snout to vent and 9 ¾ inches around – a near perfect circle! His weight surely topped 5 pounds, but I do not have the exact figure.

Our own American bullfrog, Rana (Lithobates) catesbeianus, offers its African cousin some competition. While working at the Bronx Zoo, it became my habit to toss crickets to the bullfrogs that had colonized a small artificial pond. The frogs became bold in time, and visitors enjoyed the show. On one occasion a bullfrog’s leap for food brought it directly in front of another. The larger animal grabbed the smaller, who was fully three quarters his size and, in front of 50 or so second-graders, proceeded to jam the squirming neighbor down his massive gullet. I observed this fellow thereafter – his noticeably distended abdomen flattened out in two days, after which he again gobbled crickets with enthusiasm!

Male African bullfrogs are diligent parents – they defend the eggs and dig channels to bring water to their tadpoles. You can learn more at:
http://www.amphibiaweb.org/

Keeping different species of reptiles and amphibians together is an exciting prospect that offers special rewards. However, there are many potential pitfalls. Today I’d like to mention one of the more serious of these concerns – the transmission of parasites.

Particularly troublesome are organisms that are harmless to one animal but deadly to another. The most commonly encountered of these is an amoeba known as Entamoeba invadens. Usually benign in the digestive tracts of turtles and tortoises, it can be fatal to certain lizards and snakes.

Fortunately, this amoeba can be identified via fecal exams, and such should be performed on all turtles to be housed with other reptiles. Animals found to carry E. invadens can be cleared of the parasite by treatment with Metronidizole (a second dose is given after 3 weeks to kill amoebas recently emerged from drug-resistant cysts). Follow-up fecal exams at 4-6 month intervals are a good idea.

Equally important is good husbandry practices – proper temperatures, UVB exposure, etc. – so that your pets’ immune systems will be functioning optimally. As amoebas and other parasites are usually shed in the feces, close attention to hygiene is also vital. You should be especially careful when housing closely-related species together, as a parasite adapted to one will easily infect the other. In fact, micro-organisms that are relatively harmless to one species can easily kill a relative from another part of the world. This is one reason why zoos rarely exhibit, for example, turtles from North America in the same enclosure as turtles from Europe.

Finally, the importance of caution regarding the transmission of micro-organisms between animals and people cannot be over-stressed. This concern applies to healthy individuals and especially to infants, elderly people and anyone with a compromised immune system or similar health concern. Please consult your physician as to appropriate cleaning practices and special situations. I’ll explore this important topic further in a future article, but please forward any questions or comments in the meantime.

An excellent article, Salmonella Hygiene, is available at the web site of the Association of Reptile and Amphibian Veterinarians:
www.araz.org
You can learn more about reptile and amphibian health at the very informative web site of the Arizona Exotic Animal Hospital:
www.azeah.com

Indonesia’s Kalimantan jungle toad (aka Bornean flat-headed frog), Barboula kalimantenensis, has been declared the only frog known to lack lungs. The frog itself was not collected and described until 1978. The fact that it is lung-less was released on April 10, 2008, by Dr. David Bickford of the National University of Singapore. The picture listed here is courtesy of Dr. Bickford.

This aquatic frog, known only from the Kapaus River Basin in West Kalimantan, Borneo, relies upon its skin when breathing in its habitat’s cold, highly-oxygenated waters. Its flat shape may increase the surface available for oxygen absorption, but little else is known about its natural history. Since lungs increase buoyancy, their loss may be an adaptation to life in fast-moving waters (the frog might more easily remain stable at the stream’s bottom).

Many salamanders (i.e. North America’s red-backed salamander, Plethodon cinereus) and I species of caecilian (legless amphibians) are lung-less. Most frogs, especially aquatic species such as the African clawed frog, Xenopus laevis, a popular pet, use cutaneous respiration on occasion. Others have unusual means of assisting their lungs – the Lake Titicaca frog, Telmatobius culeus, does “push-ups” to increase water flow to its oxygen-absorbing skin folds, and male West African hairy frogs, Trichobatrachus robustus, obtain oxygen via hair-like skin projections.

Logging and mining are degrading water quality in the Kalimantan jungle toad’s streams, and threaten its continued existence.

You can read more about the frogs mentioned here at:
www.globalamphibians.org

A general principle of reptile-keeping holds that “several small meals are better than one”, but there is no denying the fascination aroused by the swallowing abilities of the giant constricting snakes. I myself, even after decades of working with large snakes in zoos, was stunned when a 17 foot long anaconda I helped to capture in Venezuela disgorged a deer weighing 60 pounds (this at 3AM, below the hammock upon which I was trying to sleep)! I also observed anacondas swallowing a large side-necked turtle, Podocnemis unifilis, a 5 foot long spectacled caiman, Caiman crocodilus and a 10 pound red-footed tortoise, Geochelone carbonaria. Keepers at the Singapore Zoo informed me that a free-ranging reticulated python consumed a 40 pound cape hunting dog exhibited there.

Perhaps the most startling account is given by the Carl Hagenbeck of the Hamburg Zoo – a 25 foot long reticulated python in his collection consumed a 71 pound ibex (wild goat) several days after eating two goats of 28 and 39 pounds, for a total of 138 pounds of food within a few days! The largest meal reliably documented to have been taken by any snake seems to be the 130 pound impala eaten by an African rock python, P. sebae in South Africa(recorded by W. Rose, 1955). The group’s most “elegant” meal must surely be a Siamese cat (including bells and collar) that was taken by a reticulated python that wandered into the palace of a former king of Thailand!

Reticulated pythons are, along with anacondas, Burmese pythons, P. molurus, and African rock pythons, the only snakes known to have consumed people. I have had, unfortunately, first-hand experience with a feeding-accident fatality in NYC. Obviously, giant snake ownership is not to be undertaken lightly.

I would be very happy to learn of your own observations of snakes large and small, and to entertain your questions. Thanks.

An engrossing overview of giant snake behavior is given by famous herpetologist Clifford Pope in The Giant Snakes, 1961, A. Knopf, NY. You can also find further information at:
http://www.reptileknowledge.com/

Some of our most familiar and desirable of reptile pets, such as the leopard gecko and the brilliantly-colored day geckos, are members of a fascinating family of lizards that I would like to introduce today.

The 1,050 or more species of geckos comprise the second largest of lizard families, the Gekkonidae (the largest is the Scincidae, or skinks). They range throughout the world, reaching their greatest diversity in desert and tropical habitats. “House geckos” of several species follow human habitation and are widely transplanted, including into the southeastern USA. Geckos range in size from the various Shaerodactylus species, some of which are full grown at 1.2 inches in length, to the New Caledonian giant gecko, Rhacodactylus leachianus, a bulky creature that tops out at nearly 15 inches. Several other species, now considered extinct but which may possibly still survive in Madagascar’s forest canopy, reached 24 inches in length.

Geckos generally lay 2 eggs, although some bear live young. Arboreal types often glue their eggs to tree branches or building walls. Most are insectivorous, but many take nectar and over-ripe fruits as well. The voracious tokay gecko, Gekko gecko, consumes nestling birds, small rodents and bats, snakes and other lizards. A number of species are highly endangered while others, such as the leopard gecko, Eublepharis macularius, are pet trade staples. Many have a long association with people, being welcome in homes for their insect-catching abilities and sometimes regarded as good luck symbols. Some years back, a store in NYC even rented tokay geckos for use as roach-control agents. However, the males’ habit of calling loudly (“Tokay-Tokay!”) at 4 AM and their pugnacious dispositions rendered the scheme less-than-profitable!

The ability of many geckos to climb sheer walls (even glass) and to run upside-down on ceilings was first recorded by Aristotle in the 4th century BC. Only recently has the secret behind this remarkable phenomenon been discovered. The toes of many species are covered with layered pads known as lamellae, which in turn support thousands of microscopic hair-like structures called setae. Their action against a surface sets up a weak molecular attraction known as the van-der-Waals force, and this, it seems, is the source of their unique method of adhesion. This phenomenon is being studied with a view towards creating new adhesives for use in industry.

Members of this huge family have evolved startling adaptations to a number of basic themes. To cite just one example – depending upon the species, tails are used to distract predators (by disengaging from the body), plug burrows, extrude noxious secretions, create sound, communicate with others, convey stability while gliding, store food and grip branches.

If you have a special interest in geckos, you may wish to join the Global Gecko Association, or to visit their website for further information:
http://www.gekkota.com/