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

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.

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

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.

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