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.

In 1705, a painting of a Pink-toed Tarantula consuming a hummingbird, published in Maria S. Merian’s book on the insects of Suriname, aroused so much attention (and horror!) that all New World tarantulas are commonly termed “bird-eating spiders” to this day.  It seems now that amphibian fanciers have their own dramatic bird-eater – Limnonectes megastomias, an aquatic frog recently described from 3 locations in Thailand.

An Aquatic Ambush Predator

The newly discovered frog is largely aquatic, and apparently catches birds that come to the water’s edge to drink – quite a unique feeding strategy for a frog (I once saw a surprising film of African Side-necked Turtles catching doves in this manner).

It is assisted in hunting by large (to 2 inch) “fangs” and a head that is disproportionately large for the body.  The fangs are not true teeth but rather extensions of the jawbone, known as odontoid processes.  The African Bullfrog and the South American Horned Frogs, known also for consuming vertebrates (and biting the hand that feeds them!), also sport odontoid processes.  Insects and other frogs have also been recorded as prey.

Same Bodies, Larger Heads – Sexual Dimorphism

Interestingly, the heads and “teeth” of male Bird-eating Frogs grow much larger than those of females, despite similar body sizes.  In certain other creatures (i.e. Barbour’s Map Turtles) this strategy allows the sexes to consume different diets and, it is theorized, avoid competition.  Researchers also believe that the enlarged teeth are used in combat, as many males carry scars.

So Much to Discover

There are over 50 species classified in the genus Limnonectes- the new “bird-eater” appears most closely related to the Kuhl’s or Large-Headed Frog, L. Kuhlii, but little is known of its natural history (the photo attached is of a Kuhl’s frog).

This new species was first observed at the Sakaerat Environmental Research Station, an area that has been extensively studied for 40 years.  The fact that such a large and unique frog was able to remain undiscovered in this area illustrates the untold opportunities open to those who wish to get out and look around in just about any habitat – recently a new centipede was discovered in NYC’s Central Park!

Further Reading

Another toothed amphibian behemoth, the African Bullfrog, also takes quite large prey…to read about a most unusual frog meal, please see my article An Appetite for Cobras.

 

Limnonectes kuhlii image referenced from wikipedia and originally posted by W. Djatmiko

Many amphibian websites tend to focus only on popularly kept species. Today I’ve compiled a list that addresses both common species and less well-known topics, such as amphibian health care and caecilian husbandry.

Salamanders and Newts

Caudata.org

This is the most comprehensive salamander-oriented website available.  I’m very impressed by the depth of interest and expertise evidenced by many of the members, who are always eager to help less-experienced hobbyists.  The forum discussions are always interesting and often break new ground, and the posted articles and care sheets are top notch.

Frogs and Toads

FrogForum.net

This informative website focuses on frogs other than the “attention-grabbing” poison frogs, although discussions concerning these are welcome.  It’s very refreshing to see that North American frogs and other under-represented groups are given the spotlight here.  Popular pet trade species such as White’s treefrogs, horned frogs and African bullfrogs, are also well covered.

The discussion forums show great promise, and the care sheets and natural history information supplied are of excellent quality.

Toadily Toads

I’ve never understood why toads have always been given so little attention by amphibian enthusiasts.  They exhibit an amazing diversity of forms and lifestyles and, on the whole, make much hardier and more responsive pets than do frogs.  The folks at ToadilyToads have taken great strides in remedying this unfortunate situation.

This website deals with all aspects of toad keeping and conservation, and provides some enjoyable activities as well.  I was especially happy to see that a good deal of attention is given to encouraging local species through backyard and similar habitat improvements.

Dart Den

This site is a great resource for those who keep or are interested in learning more about the ever-popular poison frogs and their relatives (“dart frogs”, Mantella spp., Dendrobates spp., etc.).  The discussion forums are quite active, and quality care and natural history information is available.

Caecilians

Gymnophiona.org

A real find for those interested in this little-studied but fascinating amphibian order, this site posts some of the most well-researched caecilian natural history information available.  The captive care details provided are a rare and valuable resource.

Those interested in caecilian husbandry are well-situated to uncover volumes of new information on these unusual creatures; this website would serve well as a vehicle to publish such and to interact with others working with caecilians.

Health Care

Arizona Exotic Animal Hospital

I’ve long relied upon Dr. Kevin Wright, founder of the Arizona Exotic Animal Hospital, for answers to my most difficult pet and zoo animal health and husbandry questions.

One of the world’s foremost exotic animal veterinarians and coauthor of the classic Amphibian Medicine and Captive Husbandry, Dr. Wright has posted a variety of much-needed amphibian care sheets on the hospital’s website.  Covering topics ranging from general emergencies to parasites, the information contained therein is an invaluable resource to the amphibian keeper.  Hobbyists whose interests extend beyond amphibians will find a wealth of information on the care of invertebrates, fishes, reptiles, birds and mammals as well…a real treasure trove!  For information on phone and email consultations with Dr. Wright, please click here.

Conservation

Amphibian Ark

Amphibian Ark was formed in response to the wave of amphibian extinctions occurring worldwide.  The organization coordinates both field and captive-management conservation programs in association with zoos, museums and researchers worldwide.

The Amphibian Ark Newsletter, posted monthly, is the internet’s most comprehensive collection of articles dealing with amphibian research, conservation and natural history.

 

Male Great Crested Newts undergo an amazing change in appearance during the breeding season.  In Part I of this article I introduced the natural history of this most beautiful newt, and discussed how to bring it into breeding condition.  I’ll cover breeding details and raising the larvae here.

Courtship and Egg Deposition

Breeding male newts tend to fight and, although severe damage is rarely inflicted, less dominant animals may become stressed and cease feeding. Courting males position themselves near females and appear to direct pheromones towards them with their tails. Females thus stimulated follow the males, push against their tails, and eventually pick up the spermatophore that the male has dropped.

Several hundred eggs are laid, each being individually attached to an aquatic plant. Females use their rear legs to bend a plant leaf around each egg – quite an ordeal, and well-worth watching!

Adults may consume eggs and so should be removed from the aquarium after egg-laying has been completed.  If prevented from returning to land after breeding, adult crested newts usually become quite stressed, thrashing about wildly.  Some subspecies, however, can be habituated to a more-or-less permanent aquatic existence.

Raising the Larvae

Crested Newt larvae generally hatch within a month and transform into the terrestrial phase within 3 months, at which point they average 2.4 inches in length.

The larvae can be raised on chopped live blackworms, brine shrimp, daphnia and similar foods; new metamorphs can be offered 10 day old crickets, blackworms, termites and tiny sow bugs.  Sexual maturity occurs in approximately two years, at which time they will re-enter water to breed.

An Even More Flamboyant Relative

A close relative, Triturus vittatus ophryticus develops an incredibly high crest that starts at the nose area and ends at the tail. This species is now showing up in the pet trade, and can be bred in a similar manner to the Crested Newt.

Further Reading

Please see a book I’ve written, Newts and Salamanders, for more on the care and natural history of Crested Newts and their relatives.

You can learn more about the natural history of each newt in the genus Triturus here.

 

Larval Crested Newt image referenced from wikipedia and originally posted by Piet Spaans