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Live Plants in Amphibian Terrariums – Pesticide Concerns

Hello, Frank Indiviglio here.  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

Frog DisplayMost 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.

 Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

The Mantellas – Madagascar’s Answer to the Dendrobatids (Poison Frogs)

Mantella baroniHello, Frank Indiviglio here.  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 aurantiacaMantella 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!

I’ll cover the care of individual species in the future.  Until then, please write in with your questions and comments. 

Thanks,

Frank Indiviglio

Further Reading

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

The Black Pine Snake – the Rarest Species in a Well-known Group

Hello, Frank Indiviglio here.  The pine, bull and gopher snakes are a complex of 15 species that range from southern Canada through the United States and Mexico to Guatemala.  Large (to 8 feet), powerful constrictors, most species are well-studied and long-established in captivity.  The Black Pine Snake (Pituophis melanoleucus lodingi) remains, however, elusive in the wild and less well-represented in captivity.

I first worked with this striking snake at the Staten Island Zoo, home to one of the country’s most impressive snake collections, and have longed to observe it in the wild ever since.

Classification and Description

The Black Pine Snake is a melanistic form of the northern pine snake (P. m. melanoleucus) that has been given subspecies status.  One other subspecies, the Florida Pine Snake (P. m. mugitus), has been described. The Louisiana Pine Snake (pictured here) is now classified as a distinct species, P. ruthveni.

Uniformly black (rarely dark brown) above and below, the Black Pine is stoutly built.  They average 5 feet in length, with a record of 6 ½ feet.

Range and Habitat

This rare snake is limited to a few localized sites in extreme eastern Louisiana, southwestern Alabama and, possibly, Mississippi.

It is found only in association with the sandy soils of Longleaf Pine communities, a threatened habitat.  The Black Pine Snake spends most of its life underground, within pocket gopher burrows or the root systems of rotting pines.

Status

This snake has an extremely limited range and is protected by the states in which it occurs.  In the past, habitat development and collection for the pet trade threatened its survival.  Captive populations are well-established in both zoos and the private sector.

Reproduction

Mating occurs in the spring, and 3-24 eggs are laid in June-August.  The clutch is hidden in a burrow or, less frequently, below a rock or log.  The young hatch in 64-79 days at 12-18 inches in length.

Diet

The natural diet has not been thoroughly documented, but likely includes deer mice, ground squirrels, chipmunks, cotton rats, rabbits, pocket gophers and ground-nesting birds and their eggs.  Prey is killed by constriction.

This and related species usually hunt below ground, within the burrows of gophers and other rodents.  Where space does not permit constriction, these powerful snakes kill rodents by forcibly pressing them against the burrow walls.  Often a number of animals will be killed in this manner before the snake stops to feed.

Pine snakes are much valued for their rodent-catching abilities and are sometimes released around farms and grain storage facilities.

Defense

When threatened, pine snakes put on an impressive display – the body swells with inhaled air that is expelled in a loud hiss, while the tail vibrates rapidly and the head is flattened.  The snake rears up in a series of ‘S” shaped curves and strikes repeatedly.  Most will flee if given the opportunity, but they do not hesitate to bite.

Husbandry

Black Pine Snake care is fairly straightforward, and follows that of rat snakes and other Colubrids.  Please write in for further information, or see Black Rat Snake Care and Natural History for husbandry guidelines.

Captive born specimens are usually calm, although the few I have worked with were a bit high strung.  Being largely fossorial in the wild, they are ill at ease if forced to remain in the open.  Even long term captives spend a good deal of their time within shelters.

Further Reading

You can read about conservation efforts for Black Pine Snakes in Alabama here.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Breeding the Tropical Girdled Lizard (Forest Armadillo Lizard) – Part 1

Armadillo LizardHello, Frank Indiviglio here.  The Tropical Girdled Lizard (Cordylus tropidosternum) is the most readily available of the 30+ Cordylus species, and offers an excellent introduction to the group.  It is sometimes sold as the “Armadillo Lizard”, confusing purchasers who had in mind another (and, at $1,200+ each, vastly more expensive!) species with the same common name, C. cataphractus.  It also occasionally appears under the name “East African Spiny-tailed Lizard”.

Tropical Girdled Lizards in Captivity

Don’t let their inexpensive price tag mislead you – Tropical GirdledLlizards are no less interesting in appearance or behavior than their pricey cousins. In fact, the “true” Armadillo Lizard, C. cataphractus, which is no longer exported from South Africa, is one of the shyest reptiles I’ve ever encountered. 

When kept properly, these southeast African natives may reward you by reproducing, always a thrill for responsible herp keepers (judging from the size of the young, the event is less thrilling for the moms – please see below!).  While not bold, they are no as retiring as most related species, and are relatively easy to observe.

Girdled Lizards give birth to 1-4 huge live youngsters.  The hatchling pictured here, born at the Maritime Aquarium in Connecticut, is one of a litter of 2 – their total mass seemed to be nearly half that of their mother.

Next time will take a look at the influence of temperature in breeding these remarkable lizards and the care of the young.  Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Further Reading

Two subspecies of tropical Girdled Lizards appear in the pet trade; to help determine which you have, and for a key to other species in the genus, please see this reference.

Over the last several years I have helped to set up new reptile and amphibian exhibit areas for The Maritime Aquarium in Norwalk, CT (long known for its excellent collection of native marine life).  To learn more, please click here.

 

A Bird-Eating Frog is Discovered in Thailand – Research Update

Hello, Frank Indiviglio 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

Limnonectes kuhliiThe 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.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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

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