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

Like most reptile keepers, I have often marveled at the efficiency of snake digestive systems.  I attributed their abilities to break down bone to “powerful digestive enzymes”, but recent research has shown that, at least for Burmese Pythons (Python molurus), a far more complex and amazing process is at work.

Digesting Large Vertebrates

I’ve observed some quite large snake feasts – a Red Foot Tortoise and a 60 pound deer taken by Green Anacondas (the tortoise was an unfortunate exhibit mate; the deer fell to an anaconda at my study site in Venezuela) and 40 pound pigs regularly fed to Reticulated and Burmese Pythons under my care at the Bronx Zoo, for example.

A few shell scutes, hoofs, some bone fragments and fur where all that passed in the feces of these snakes – the rest being digested.  How do they do it?

Bone-Digesting Cells

Research at the Louis Pasteur and Indiana Universities has revealed that, after feeding, the digestive systems of Burmese Pythons undergo a dramatic transformation.  New cells are produced and worn-out cells die and are eliminated in preparation for the work at hand.

Studies of the small intestine have uncovered a new type of cell, previously unknown to science.  These cells are responsible for degrading bone and releasing its components into the snake’s bloodstream.  This process promotes efficient calcium absorption, and may be the reason that most captive snakes do not require a UVB source if fed a diet comprised of whole rats, mice and other vertebrates.

Warm-Blooded Snakes?  Not Quite, but…

We’ve known for some time now that Burmese Pythons break the “cold-blooded” rule when digesting their meals.  While most snakes must seek out a hot basking spot in order to maximize digestion, Burmese Pythons can actually raise their internal temperatures without an external heat source! 

Further Reading

Please see Big Snake Meals for some examples of how large (and unusual) snake prey can be.

To read about recent research concerning another unusual snake feeding adaptation, please see How Snakes Grow despite Food Deprivation.

An account of the original research showing that pythons can raise their body temperatures may be found in this Journal of Herpetology article.

 

Please see Parts I and II of this article for additional information on garter snake husbandry and natural history.  Today I’ll cover some often over-looked aspects of garter snake care that may help to explain why these relatively hardy snakes, and the related ribbon and water snakes, often fail to live as long as might be expected in captivity.

Thermal Gradient

A thermal gradient (varying temperatures within the terrarium) is beneficial to nearly all reptiles, but seems particularly important in maintaining the health of captive garter snakes.  This is especially true for Butler’s Garter Snakes (T. butleri), Common Garter Snakes (T. sirtalis) and others that range into the northern half of the USA.

Depending upon the species in question, garter, ribbon and water snakes do best at an ambient temperature of 72-82 F, with a warmer basking site (90-95 F) and a drop to 68 F or so at night.  Northern species should ideally be subjected to a winter cooling-off period, even if breeding is not contemplated.

UVA Light

There is some evidence that garter and related snakes (as well as Rough and Smooth Green Snakes, Opheodrys aestivus and O. vernalis), may benefit from exposure to UVA light.

A ZooMed Repti Halogen Bulb should be provided during their normal daytime cycle.  Even if not strictly necessary for survival, UVA encourages natural behavior, reproduction and, possibly, a strong immune system.

UVB Light

While snakes have not been shown to require UVB light exposure, anecdotal reports from successful garter and water snake keepers lead me to believe that these snakes may differ from most in this regard.

The Zoo Med 2.0 fluorescent lamp is specifically designed for animals needing moderate amounts of UVB light, and may be a prudent addition to the garter snake terrarium.  This bulb also supports vigorous plant growth…in contrast to most snake species, garter and ribbon snakes are very well-suited for terrariums housing sturdy live plants.

Further Reading

Laboratory guidelines concerning the importance of thermal gradients and related aspects of reptile care are posted here.

Next time we’ll cover nutrition and the care of individual garter snake species.

 

Once again we need to ask your help in opposing a poorly-researched effort to limit the responsible ownership of any and all pythons, including harmless species and those which have benefitted from the captive breeding efforts of hobbyists.

Senate Bill 373, which is up for consideration on this Thursday, December 3, 2009, seeks to prohibit the ownership of all snakes within the genus Python by classifying them as “injurious wildlife” under the Lacey Act.  The lack of foresight and scientific research that resulted in ball pythons being considered to be equally threatening to the environment as Burmese pythons is obvious.

In July of this year, the overwhelming response of reptile owners and the pet industry was instrumental in limiting the scope of a similar bill, HR 2811, to Burmese and African rock pythons only.  Our experience with that bill shows very clearly that our involvement in government action is critical, and that the system does work – but only if we participate in a timely manner.

It is critical that we act right now, as the Senate vote on this bill will be taken in 2 days – December 3, 2009.

The Pet Industry Joint Advisory Council has set up a simple method for you to register your opinion with the Senate here.  You can read more about the scope of the bill there as well.  Please take action now – we changed the future of our hobby and, in many cases, our professions, in July, and we can again.

For more valuable information concerning reptile hobbyists, you can also visit the US Association of Reptile Keepers (USARK).

 

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 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.