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

Live plants are very useful in creating amphibian terrariums that are both attractive to the eye and beneficial for the animals housed therein.  However, amphibian skin is permeable to substances as small as oxygen molecules.  Several readers have recently questioned whether pesticides used on terrarium plants could harm amphibians through physical contact.

Examples of Contact Poisoning

Most chemicals do readily penetrate the skin of frogs and salamanders and can kill them in short order.  Pesticides on plants are a concern, even though they will not be consumed.

A coworker of mine once lost a group of Blomberg’s Toads and Smoky Jungle Frogs after confining them to quickly-rinsed enclosure that had been cleaned with Nolvasan, and I witnessed a Leopard Frog expire after being put into a pail that had previously housed a Fowler’s Toad (the stressed toad had apparently released skin toxins).

Locating Safe Plants

Some commercial growers who cater to zoos and the pet trade claim not to use pesticides.  The reptile department of your local zoo, if reachable, might be a good place to start when searching for reputable plant suppliers.  Pet stores specializing in tropical fishes usually buy pesticide-free plants as well. Some, especially those that carry plants for outdoor ponds, may stock emergent species or others suitable for use with amphibians.

Removing Surface Pesticides

If you are unsure of pesticide presence, discard the soil that arrived with the plant and rinse the plant, roots and all, vigorously.  Finish up by submerging the plant and swishing it about underwater.  Some recommend a light soap solution, but I have not found this to be necessary.

Systemic Pesticides

A greater potential concern is posed by systemic pesticides, which do not remain on the surface but rather work their way into the plant’s tissues.  Fortunately, these are not commonly used with on commercially raised plants suitable for terrariums.

One colleague of mine did run into a situation involving systemic pesticides.  He held the plants for 30 days before introducing them to his exhibits.  He had no problems with any of several tree frog species that utilized the plants frequently, and eventually used them with arboreal salamanders (Bolitoglossa spp.) as well.  This time frame is based on observation rather than rigid testing, but has proven quite dependable.

Further Reading

Those who keep herbivorous turtles and lizards also need to be concerned about potentially lethal plants.  The species listed in my article Common Plants that are Toxic to Birds  should be avoided by herp keepers as well.

To learn about growing safe plants for herbivorous reptiles, please see Reptile Gardens.

Madagascar’s Mantellas or Golden Frogs (Family Mantellidae) are, in many ways, the ecological equivalents of Latin America’s Poison Frogs (Family Dendrobatidae), and illustrate nicely the concept of convergent evolution – unrelated animals from different parts of the world that have developed similar adaptations.  Although less commonly kept than the poison frogs, these tiny, brilliantly-colored gems are gaining in popularity.  Following is a brief overview of the group.

Range and Diversity

Mantellas are found only on Madagascar, off the southeast coast of Africa, and are unique enough to warrant their own family, Mantellidae.  Sixteen species have been described thus far, but that number will almost certainly increase as the group is studied more closely.  Nearly all are exceptionally colorful – more so than the better known Poison Frogs (Dendrobates spp.) in many cases.

Similarities to Poison Frogs

Both Mantellas and Poison Frogs are small, brightly-colored, diurnal (active by day), and usually make little attempt to conceal themselves.  All forage on land or in trees, are protected by virulent skin toxins, exhibit complex breeding behaviors, and lay eggs in on land.

Mantella reproductive strategies roughly follow those of the Poison Frogs.  Males call during the day from exposed sites on land – light markings on the vocal sacs may serve as a visual stimulus to females.  They wrestle for dominance, with the loser being flipped onto his back but otherwise unharmed. Ten to thirty eggs, which are fertilized externally, are deposited in nests below leaf litter.

Tadpole development has been little studied; those which have been researched hatch in 2-7 days and wriggle or are washed by rain to temporary pools and brooks.  They feed upon algae and decaying plants and animals, and transform into frogs in 6-8 weeks.  Sexual maturity is attained in 12-14 months.

Mantellas in the Terrarium

Mantellas may be kept in much the same manner as most poison frogs but, being even smaller, they are a bit harder to feed.  A source of springtails, fruit flies and pinhead crickets is a must.

Despite their diminutive statures, Mantellas are efficient predators with quite large appetites – a 1.8 inch long Bronze Mantella (Mantella betsilio) was observed to consume 53 ants in just 30 minutes!

Further Reading

A review of the status of the various mantellas and the CITES proposal for their protection is posted here.

Please see Part I of this article for background information on these snake-keepers’ favorites.  Garter Snakes and the closely related ribbon and water snakes usually make hardy captives, yet there are very few records of individuals surviving over 10 years.  I believe this may have to do with some of their unique environmental and dietary needs (I’ll cover temperature, light and diet in Part III of this article).

Natural vs. Captive Habitats

Nearly all garter and ribbon snakes favor swamps, wet meadows, pond edges and other moist habitats.  Oddly, however, they are very susceptible to skin infections (“blister disease”) when kept on damp substrates – even more so than snakes native to dry environments.  This holds true even for those that spend a great deal of time in the water, such as the Aquatic Garter Snake (Thamnophis couchi), the Ribbon Snake (T. sauritus) and the True Water Snakes (Nerodia sp.).

While all should be given water in which to soak, the substrate must remain dry.  The aforementioned species may be kept in semi-aquatic terrariums that allow for swimming, but they must have access to warm, dry basking sites (branches over water work well).  Shy specimens that will not bask should be moved into terrestrial situations with just a bowl of water available.

Curing Blister Disease

A Northern Water Snake (Nerodia  sipedon) that I kept decades ago developed skin blisters after only 2 weeks of a largely aquatic existence.  I wrote to famed reptile man Wayne King, then curator of reptiles at the Bronx Zoo.  His advice to move the animal to a dry terrarium and provide a warm but sheltered basking site worked like a charm, and the snake’s skin condition cleared within 10 days.

Further Reading

An excellent article on the unique Aquatic Garter Snake, including habitat photos, is posted here.

As autumn approaches I invariably receive questions from reptile owners whose pets have lost interest in food.  This most commonly occurs among Red Eared Sliders, Box and Painted Turtles, and other North American species, but may show up in lizards and snakes as well.

Amphibians in general, and reptiles from regions without a seasonal change, are largely immune.  Bear in mind, however, that many species native to warm climates do experience a cool season – Bearded Dragons are a prime example, with certain populations hibernating in the wild.

Internal Controls on Behavior

It is common for native reptiles to slow down or stop feeding as the seasons change; often circadian rhythms (“internal clocks”) control this, and they will not feed even if kept warm. As long as the animals are otherwise in good health, they will be fine.  We are learning that reptiles have amazing abilities to alter their metabolisms to suit local conditions (please see article below).  Gharials (fish eating crocodilians) that I kept for 17 years at the Bronx Zoo went off feed annually, right in sync with wintertime in their native Pakistan.  Despite being kept at 86-92 F, and moving about daily, they lost almost no weight over their 3 month fasting period.

Keeping Turtles in Winter

Sliders, Snapping Turtles and others that refuse to feed as fall approaches can be kept in water that is at average room temperature (65-68F) or a bit higher over the winter.  Leave their UVB and basking lights on during the day, as they will continue to bask and move about.  You can offer food 1-2x per week, but they will likely not eat much.  Sick or stressed animals are another matter…please write in if you need advice.
Actually putting reptiles into true hibernation by lowering temperatures significantly is tricky, although often an important breeding stimulus.  Please write in if you need further information.

Future Research -Your Observations Needed

One thing I’ve noticed, and which I’d like to research further, is that wild-caught turtles, even if taken into captivity on the day of hatching, usually stop feeding in the winter, while captive-hatched animals of the same species feed throughout the year.  I would be very interested to hear from readers with similar or different experiences, thanks.

Further Reading

Please see Hibernation in Captive Bearded Dragons for specific information on these popular pets.

There is some amazing new information coming to light on snake metabolisms.  Please check out How Snakes Grow During Times of Food Deprivation.

One of the most over-looked aspects of proper turtle care is the provision of a secure place to hide.  It makes sense that a hiding place would seem unnecessary – after all, turtles can simply withdraw into their shells when threatened.  However, it’s not that simple (as usual!).

Shelter Use in Nature and Captivity

Even though their shells are often hard, and offer excellent camouflage – imagine a box turtle on a forest floor or a leopard tortoise among brush – most turtles become quite stressed if denied a secure place to hide.  Even bold, long-term captives prefer a shelter, at least for sleeping.

Particularly retiring species, such as mata mata, bog and Malayan snail-eating turtles, will often fail to thrive if kept in bare surroundings. Hatchlings, even of common snapping turtles and other aggressive species, are consumed by predators ranging from giant water bugs to herons…most are always “on guard” and will refuse to eat unless given ample cover.

Note: at 80+ pounds, the Common Snapper Pictured here is among the heaviest ever recorded. He is on exhibit at The Cold Spring Harbor Fish Hatchery, which houses an extensive collection of native reptiles and amphibians.

Useful Shelters for Terrestrial and Aquatic Turtles

The Zoo Med Turtle Hut, available in 5 sizes, suits nearly all land-dwelling turtles.  R Zilla Rock Dens sink, and so can be used on land or underwater (check that aquatic turtles cannot lodge themselves inside too tightly, and provide larger shelters as they grow).

The Zoo Med Turtle Dock can be set up to serve both as a basking platform and hideaway for aquatic turtles.  When used in shallow water, the sloping side, top of the platform and tank’s wall form a nice underwater cave readily used by young painted, spotted, mud and other turtles.

Next time we’ll take a look at a few species that have special needs, and I’ll add a note about an old turtle of mine that hides within a unique, very old “cave”.  Please write in with your questions and comments. 

Further Reading

For an interesting report on Eastern box turtle natural history, including the use of shelters in the wild, please look here.