Hello, Frank Indiviglio here.  Garter Snakes (Thamnophis ssp.) have long introduced aspiring herpetologists to snake-keeping and remain popular today.  A number of North America’s 30+ species are regularly available in the pet trade, and they remain the most commonly encountered free-living snakes in most areas.  Although often thought of as “beginner’s snakes”, I maintain that garters possess a unique combination of characteristics that render them fascinating additions to any private or public collection…they certainly have been a source of many of my most interesting observations.

Range

Garter Snakes of one or another species range from southern Canada to Central America, and reach their greatest diversity in the United States.

Those best suited to captivity are classified in the genus Thamnophis.  Along with ribbon and water snakes, this genus is placed within the subfamily Natricinae and the family Colubridae. 

Diet

Frogs, tadpoles, earthworms, salamanders, fishes and insects comprise the diets of most species.  Several are immune to the virulent skin toxins of amphibians such as California newts, which have caused human fatalities when ingested, and toxin-protected American toads are the primary food of plains garter snakes (T. radix) and others.  Some, such as the giant garter snake (T. couchi gigs), take rodents on occasion.

Attractive Attributes

A preference for fishes and earthworms, and a willingness to accept nonliving food items (garters sometimes consume road-killed frogs) greatly simplifies garter snake husbandry, and suits them well to those who prefer not to keep rodent-eating snakes. 

All bear live young and, when properly maintained, are likely to breed.  Although wild-caught snakes will bite and release musk when handled, they tame down readily…the most frequently kept species, the common garter snake (T. sirtalis), is especially docile. 

Eliciting Natural Behavior

What I especially favor about garter snakes is that they can be kept in planted, naturalistic terrariums – a difficult prospect where most other snakes are concerned. 

When kept so they reveal a great many of their natural behaviors – far more than is the case for large snakes maintained in bare enclosures.  A pair of garter snakes in a terrarium stocked with plants, branches, hideaways and a pool will provide you with insights into snake behavior that are not easy to come by otherwise.

A Wide Spectrum of Colors

While not subject to the intensive captive breeding efforts applied to other species, garter snakes are being kept by several breeders interested in developing unique color morphs.  Already, some spectacular results have been achieved, and more can be expected.  

This is not to say that selective breeding is necessary where garter snake colors are involved.  All are interestingly marked, and a great many species sport bright colors.  In fact, a subspecies of the common garter, known as the San Francisco garter snake (T. sirtalis tetrataenia), is one of the most beautiful snakes to be found anywhere.  Unfortunately, it is highly endangered and may not be kept in the USA, but by all means try to see it in zoo collection if possible. 

Individual variation among animals of the same species is the rule when it comes to garter snakes, so all sorts of interesting surprises await those who seek out these most fascinating reptiles.

Further Reading

Please see my article Keeping Snakes in Naturalistic Terrariums for some ideas concerning planted habitats for garter snakes.

To read about captive breeding and in situ conservation programs for the San Francisco garter snake, please see here.

Next time we’ll cover the basics of garter snake keeping, and look at a few interesting species in detail. 

Until then, please write in with your questions and comments. 

Thanks,

Frank Indiviglio

Texas Garter Snake image referenced from wikipedia and originally posted by Dawson

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Hello, Frank Indiviglio here.  Today’s update, while concerning an animal not suited as a pet (the American Alligator, Alligator mississippiensis) will I’m sure will be of interest to all who keep or study reptiles.  Scientists from the Savannah River Ecology Lab, working with alligators in Louisiana’s Rockefeller Wildlife Refuge, were surprised to find a high degree of mate fidelity in their study population.

Remaining Faithful Despite Choices

Writing in the October, 2009 issue of Molecular Ecology, the researchers explained that 70% of the female alligators they studied over a 10 year period mated with the same male each year.  This is the first time such behavior has been documented in any Crocodilian, and is rendered even more interesting by the fact that the refuge supports a very dense population of alligators, and females freely move through the territories of a great many males.

A Look Back in Time

Crocodilians are the sole surviving reptiles classified as Archosaurs, a group that includes the dinosaurs and which gave rise to the birds (some taxonomists argue that alligators are closely related to birds, and should be removed from the Class Reptilia).  It is hoped that this newly discovered alligator mating behavior will reveal something about the mating strategies of dinosaurs and the ancestors of modern day birds.

Working With Crocodilians

Crocodilians make poor pets, but, as you see from the accompanying photos, they can be exciting to work with in zoos (please be in touch if you’re considering a career in herpetology). 

A pair of Cuban crocodiles (Crocodylus rhombifer) under my care at the Bronx Zoo produced young together over a period spanning 40 years (the photo shows some of the “little ones” rushing to a meal) – but, unlike the Louisiana gators, they were housed together, without others of their kind, and so had little choice!

Further Reading

To read about how other research with alligators is granting us a peek at how dinosaurs may have lived, please see this piece.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here. 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.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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

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Hello, Frank Indiviglio here.  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.

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.

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  The tadpoles of American Toads (Bufo/Anaxyrus americanus) and Fowler’s Toads (B. woodhousei fowleri), and of related US natives, are frequently collected by herpers young and old and taken home to raise.  They usually prove quite hardy, and, even on nutrient-poor diets (i.e. lettuce), transform into tiny toadlets within a few weeks. 

Toad Maladies

Young toads often prove difficult to raise however, and each year I receive questions concerning the same 2 problems - bloating and paralysis (difficulty hopping, problems catching food, etc.).  I’ve run across this myself when raising American toad tadpoles for a release program in NYC, where most of the tadpoles transformed, but died soon after.

Nutritional Deficiencies

I’ve come to believe that 2 distinct problems are at work.  Difficulty in using the rear legs is probably linked to deficiency in calcium or another nutrient, but efforts to reverse it, at least in small toads, have proven unsuccessful.
Using supplements on the food given newly transformed toads helps, but we really do not know what most species, especially North American natives, actually require. 
Tadpole nutrition is another area that needs investigation.  Poorly nourished tadpoles may transform, but then die several weeks later…I’ve had this happen on a number of occasions over the years, with several species, even the relatively indestructible African clawed frog (Xenopus laevis).

Bacterial Infection

Bloating is usually a byproduct of a bacterial infection, and may be connected to nutrition.  Toads already weakened by a nutritional deficiency may be more likely to become infected with bacteria that healthier clutch mates fight off – hence both symptoms in 1 toad.  This is based mainly on anecdotal evidence, but does seem to happen time and time again, and with several species.

Natural Mortality

Another point to bear in mind is that, among species that lay huge clutches, a great many tadpoles will not survive even under the best of circumstances.  Some turtles lay infertile eggs, apparently to satiate predators and take attention away from viable ones - I have no hard evidence, but I would not be surprised to learn that weaker tadpoles serve a similar function.

Feeding Tadpoles and Young Toads

Most native toad tadpoles are omnivorous.  Try to provide them with as much variety as possible, and bear in mind that, in large groups, smaller, weaker individuals are easily out-competed at feeding time.  I’ve had good luck raising tadpoles on a diet comprised of tropical fish food flakes, algae tablets and kale pre-soaked in hot water (this breaks down thick cell walls). Metamorphs (newly transformed toads) consume scores of species of leaf litter invertebrates in the wild, complicating our job in raising them.  In addition to tiny frog standards such as fruit flies, springtails and pinhead crickets, you might try collecting tiny invertebrates as toad food (please see article below).

Further Reading

Please see my article Leaf Litter Invertebrates for information on collecting live food for tiny amphibian pets.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Haswell's Frog tadpole image referenced from wikipedia and originally posted by LiquidGhoul

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Hello, Frank Indiviglio here.  Tarantulas and scorpions have long been invertebrate pet staples, with over 150 species being captive bred in large numbers.  However, insect keeping, always popular in Japan but much less so elsewhere, is now coming into its own in the USA.  I recently found that over 50 stick and leaf insect, 30 mantid, 25 cockroach and 25 beetle species, along with numerous grasshoppers, katydids, butterflies and moths, are now regularly bred in captivity. 

Velvet Ants, Tarantula Wasps, Giant Water Bugs and innumerable others are also kept in smaller numbers, and are growing in popularity.  An aquatic insect exhibit I recently designed for the Brooklyn Children’s Museum, featuring the usually ignored Water Scorpions and Whirligig, diving and water scavenger beetles, is a big hit with visitors.

Grand Possibilities

The potential diversity of insects that may be kept in captivity is limitless, and many exhibit their entire life cycles and full range of behaviors in a relatively limited space and time span.  Those who keep insects are offered the real possibility of discovering new information.

Conservation Value

Much of what has been learned by those keeping insects in private and public collections has conservation value.  Captive breeding and reintroduction programs for endangered species ranging from Sphinx Moths in Arizona to Burying Beetles in Rhode Island have yielded promising results.

Other Invertebrates

An astonishing array of other terrestrial invertebrates are also being kept and bred in captivity, including Banana Slugs, trapdoor, orb-weaver, wolf and crab spiders, centipedes, millipedes, Vinegaroons and Sun Scorpions, to name just a few.  

Further Reading

Japan’s Tama Zoo boasts 2 giant insect houses...be forewarned, insect aficionados who visit will emerge in shock, as did I!

Phasmids (walking sticks and walking leaves) have long been popular as captives in Europe. Photos of many of the nearly 3,000 described species, along with natural history notes, are posted here.

Founded in 1892, and with roots dating to 1872, the NY Entomological Society is an invaluable resource for insect enthusiasts. To learn more about this well-respected group and its publications, please visit their website.

I plan to write about the care of a variety of insects and other invertebrates in the future.  Please write in with your insect observations and suggestions for species to highlight. 

Thanks,

until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  I’ve been fortunate in having had many adventures with reptiles.  Some took place in the exotic locales I dreamed of visiting as a child, but one of my first was situated in far less promising surroundings – the sewers below the Bronx, in NYC!

The Legend

I grew up hearing tales of huge alligators that supposedly cruised the sewers of NYC, warmed by the steamy air and gorging on rats, roaches and garbage.  In the 1950’s and 60’s, huge numbers of baby Spectacled Caimans (Caiman crocodylus), dubbed “alligators”, were sold to tourists visiting Florida.  In fact, I was presented with just such a creature by my grandfather.  As the story went, the “gators” wound up in sewers after being flushed or dropped there when they became ill or too large for their owners to manage. 

My Golden Opportunity

When I was 10 or 11 years old, construction on the street outside my home gave me a long-awaited opportunity…the chance to sneak down into the sewers on an alligator hunt.  I couldn’t imagine a more fortunate set of circumstances, and felt sorry for the many children deprived of such a grand adventure! 

Provisioned with a hook, line and pilfered cold cuts, I spent many summer afternoons stalking the mythical beasts below the streets of the Bronx.  I did see “wildlife” - rats, mice and roaches - but I did not catch any alligators (or infectious diseases, thankfully!).  

Fortunately, my interests were wide, and with the aid of my books and the (very!) patient, kind-hearted folks at the American Museum of Natural History’s Invertebrate Department, I was able to determine that at least 3 different species of cockroach roamed the area.

The Reality of NYC’s Sewer Gators

Of course, NYC’s sewer system is a less than ideal home for crocodilians of any type – cold winter temperatures, a lack of sunlight and a poor diet would doom the creatures to brief lives, if ever they were there. 

I recently expressed that opinion in an interview that was scheduled to air on the TV show “Monster Quest”.  However, I upon watching the episode I found that I had been “deleted” – hopefully because my comments were not “dramatic” enough, and not due to my poor on-air appearance!   

Some Real NYC Crocodilians

About 10 years ago, a young Spectacled Caiman did wind up being caught in a filter at a water treatment plant on the Bronx River…perhaps the first solid evidence of a free-living crocodilian in NYC.  The animal had likely been dumped by its owner a short time earlier, but we could not trace its history. 

A young alligator, released into a lake in Central Park a few years back, put Manhattan on the map as crocodilian “habitat”.

Working with Crocs

Happily, as time went on I was able to work with 15 or so species of crocodilians in zoos and the wild.  Please see the attached photos – the beast charging me is a marsh crocodile,  Crocodylus palustris, the long-snouted fellow being led into the net is an Indian gharial, Gavialis gangeticus, and the white specimen is an albino American alligator, Alligator mississippiensis.

Further Reading

For more on sewer gators and additional photos, please check out the interview I gave to Columbia University’s online magazine.

 Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  Few amphibians exhibit a more dramatic change in appearance than male Crested Newts in breeding condition.  It really is something to see and, fortunately, breeding this species is actually quite feasible.  Breeding the crested newt in captivity also has great conservation value, as this species is in decline throughout Europe.  Furthermore, any information garnered is applicable to other species of concern, including the Alpine Newt, Triturus alpestris and the Swiss Newt, T. helveticus.

Natural History

The Crested Newt, which may reach 6.4 inches in length, is grayish to black above and orange with round black spots below.   

Living a largely terrestrial existence for most of the year, both sexes enter breeding ponds in late winter or early spring.  At this point, the males’ colors intensify and a large, comb-like dorsal crest develops. In both sexes the tail also becomes more paddle-like to facilitate swimming. Males also usually develop a white line along the sides of the tail, while reproductively active females sport a white line down the back.

Bringing Newts into Breeding Condition

While breeding may occur spontaneously in captivity, the most consistent results will be obtained if the newts are over-wintered at 36-42 F.  An increase in water depth may stimulate breeding outside of the normal cycle, but fewer viable eggs will be produced).

Upon emergence from hibernation, the newts should be housed in aquarium, or their terrestrial terrarium should be modified to provide a large water area. Resting sites such as cork bark slabs or basking platforms should be provided. 

Due to their unique egg-laying behavior (females fold a plant leaf around each egg), crested newts slated for breeding are best housed in well-lit aquariums stocked with live plants.  The water should, if possible, be maintained at 54-65 F (a cool basement or garage often proves ideal).

We’ll take a look at raising the larvae next week. 

Further Reading

Please see my book, Newts and Salamanders for more on the care and natural history of Crested Newts and their relatives.

A conservation plan for wild crested newts in Great Britain, and natural history information, is posted here.

Please write in with your questions and comments. 

 
Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  In  Part I of this article we looked at the importance of calcium, leaf litter and decaying wood in the diet of the African giant millipede (Achispirospreptus gigas) and its relatives. 

Research Needed

Few field studies have been made of millipedes in the wild, and we therefore know little about their exact nutritional needs.  Based on experience with related species, and in the hopes of providing as many nutrients as possible, I began offering African giant millipedes a wide variety of food items.  With the help of colleagues here and abroad, I eventually arrived at a diet that has allowed me to breed a number of native and exotic millipedes, and to maintain individual animals for over 10 years.

A Useful Millipede Diet

In addition to leaf litter and wood (please see Part I of this article), I feed most millipedes a mixed salad of yam, carrot, kale, cucumber, apple, banana and a wide variety of other fruits and vegetables.  To this is added moistened insect gut-loading diet and tropical fish flakes, both of which supply necessary protein, and a bit of Forest Tortoise Food.

San Francisco Bay Prepared Tortoise Food is a convenient means of providing a wide variety of nutritious foods, and is readily accepted by many millipedes. I use this as an occasional supplement, or mix it into the regular salad.  All food offered is powdered with Reptocal.

Further Reading

You can read more about giant millipedes and how they are kept at the Fort Worth Zoo.

Millipedes have an unusual defense mechanism, which, in some cases, is exploited by monkeys.  To read about my experiences and “close call” with millipede-generated cyanide, please see Millipede Emergency: the Dark Side of a Peaceful Terrarium Invertebrate.

We still have a lot to learn…please write in with your own millipede diets and any questions you may have. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  Despite - or perhaps because of - its immense size, impressive armament of teeth and scarcity, the spectacular Crocodile Monitor Lizard (Varanus salvadorii) is often considered the crown jewel of private and public monitor collections.

I became acquainted with these formidable giants when they were first imported into the USA, and have cared for several at the Bronx and Staten Island Zoos.  Their husbandry is straightforward, but little is known about their lives in the wild.  Today I would like to summarize what we do know; please see the article referenced below for notes on captive care.

Description

Crocodile Monitors approach 9 feet in length - nearly as long as the famed Komodo Dragon, but less stoutly built.  There are recurring but unverified reports of much longer individuals. 

The Crocodile Monitor’s prehensile tail often exceeds 5 feet in length.  The body is dark gray to black in color and marked with yellow spots, making for quite a spectacular appearance.  The snout area, especially in mature males, is large and bulbous.

Crocodile Monitors are unusually large for canopy dwelling lizards…the 3 foot long black tree monitor is far more typical.  However, aided by slender bodies, long claws and prehensile tails, they are very agile climbers. 

Their teeth are unique among monitors, being serrated and over-lapping – possibly an adaptation for carrying large prey high above the forest floor.

Range and Habitat

Crocodile Monitors are found only in southern New Guinea.  Highly arboreal, they seem restricted to the canopies of mangrove swamps and lowland forests along rivers. 

Status

Little studied due to the inaccessibility of their habitat, the Crocodile Monitor’s limited range renders it a conservation concern.  Listed on CITES Appendix II.

Reproduction

Females lay 6-12 eggs at a time, and up to 3 clutches per year in captivity (multiple clutches may be a function of food availability), with arboreal nest sites being favored.  In common with other tree-dwelling monitors, they likely deposit eggs in tree hollows and similar sites above ground in the wild.

Diet

Their natural diet has been little studied, but probably includes nearly any animal that can be overpowered.  Likely candidates would be cuscus, tree kangaroos, naked-tailed rats, bandicoots, possums, bats, birds, frogs, snakes, lizards, invertebrates and carrion. 

An Undiscovered Giant in New Guinea?

Long a creature of legend, the Crocodile Monitor is the source of rumors alleging “Papuan Dragons” of 20 feet in length.  This specie’s habitat is inaccessible and barely explored….I like to believe that it or an as yet un-described monitor may indeed reach such lengths. 

A Calculating Reptile

Like all Varanids, Crocodile Monitors are highly intelligent.  One huge adult that escaped its enclosure at the Bronx Zoo wedged himself behind a cage while attempting to hide from myself and a co-worker.  As we moved into position to flush him, he very deliberately peered around first one and then the other side of his hideout, trying to keep us both in sight.  When we backed off, he followed our progress, again changing position periodically to ascertain where we were. 

The lizard remained stationary while we were near, and only ran when we gave him some space.  When he did move, the old fellow made unerringly for a more secure retreat that he had obviously “decided upon” while in hiding.

Further Reading

Please see my article Monitor Lizards: an Overview for information about the captive care of this and related species.

A comprehensive field report on the crocodile monitor’s habitat is posted here.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Crocodile Monitor image referenced from wikipedia and originally posted by Ltshears

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