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

The process of hibernation (or brumation) in reptiles and amphibians seems subject to a great many factors.  For example, I have noticed that spotted and Eastern box turtles, and other temperate North American species, vary greatly in this regard.  In captivity, wild-caught individuals usually slow down (activity and feeding) during the winter, even if kept warm and given a photoperiod of 12 hours.  Captive-born animals of the same species most often continue to feed throughout the winter.

Green frogs, garter snakes, musk turtles and others, however, usually stay active if kept warm in winter, even if wild-caught.

A recent email from a colleague brought up the subject of bearded dragons.  His animal becomes lethargic and ceases feeding in October, despite a long photoperiod, and high ambient and basking temperatures.  Most bearded dragons in the US pet trade are several generations removed from the wild, yet the tendency to hibernate persists in some.  Many bearded dragons, however, remain active all year.   I am wondering if what we are seeing is related to the natural range of our pets’ ancestors… perhaps those from certain areas hibernate in the wild and retain this pattern in captivity?

A Request for Help

Internal (circadian) rhythms exert their influence on most animals, and an understanding of their workings is vital from both a pet-keeping and conservation point of view.  I would greatly appreciate being informed of any seasonal changes in activity that you notice among your pets.

Some North American turtles are incredibly cold-tolerant, and are being studied to see if the mechanisms they use might be applied to the possible storage of human organs destined for transplant.  The abstract of an interesting The Journal of Herpetology article is posted at:

http://www.jstor.org/pss/1565569

If you’re looking for general care information on bearded dragons, check out my article: Bearded Dragon Natural History and Captive Care.

The house cricket is something of an insect oddity…at once both an adaptable, widely introduced species and a somewhat delicate captive.  Native to southwestern Asia, it fares poorly in the damp conditions favored by field crickets and other North American species.

Providing a Water Source: the advantages of gels

House crickets will not survive long in damp conditions, but they do need to drink quite a bit of water, and herein lays the main problem in keeping them.

The crickets drown rapidly in standing water, and cotton or gravel-filled bowls foul quickly.  Stagnant water, and mold on damp sponges or oranges (2 other common methods of providing water) supports bacteria that seems, for reasons not completely understood, to rapidly decimate cricket colonies.  Misting the colony, a useful technique as regard many insects, is worse, and again will result in heavy losses.

The advent of gel-based cricket water substitutes is one of the most important recent innovations in food animal maintenance.  These products save time and money by cutting down on losses.  More importantly, crickets that live longer have improved chances of consuming a nutritious diet, and thus are themselves a more valuable pet food.

I use Cricket Drink and R-Zilla Cricket Calcium Drink Supplement exclusively.  Both are fortified with calcium and other nutrients, and are readily consumed by crickets.  No other water source is necessary.  Millipedes and sow bugs will also feed upon these gel cubes, and they would be well-worth trying on scorpions and tarantulas.

A Warning: Condensation

Even when fruit and standing water is dispensed with, be sure to guard against condensation buildup.  This occurs most frequently in crowded enclosures, and will wipe out your colony in short order.  Adequate ventilation and roomy holding containers are of key importance in avoiding damp conditions.

Next time I’ll review some commercial cricket diets.  Please write in with your own tips for keeping crickets and other food animals.

You can read about the natural history of the house cricket here.

Please see Parts I and 2 of this article for information on housing and diet. Today I’ll conclude with some thoughts on toads in community terrariums and the wild.

Tank mates
American toads are quite peaceful towards one another, but larger animals will nudge others from food, so keep an eye on them at feeding time. The conditions favored by toads are also suited to a number of other interesting creatures, and their diets and temperaments suit them ideally to community terrariums.

Compatible animals include spotted, tiger, marbled, slimy and other terrestrial salamanders (see photo), wood frogs (see photo), gray, barking, green and other native treefrogs and land snails. Assuming that space permits the establishment of a warm basking area (without over-heating the toads), you can also house a number of small reptiles with American toads. I have had kept them with 5-lined skinks, Italian wall lizards, green anoles, DeKay’s (brown) snakes, ring-necked snakes and smooth green snakes. There are other possible toad-companions as well – please write in if you would like more suggestions.

Free-Living Pets
American toads will utilize favored burrows for years on end, with wild individuals documented as remaining within the same territory for over 20 years. If you have a population living nearby, encourage the toads to stay nearby by providing a shallow, easily-exited pool and some retreats in the form of half-buried, inverted clay flower pots. Resident toads will learn to gather at an outdoor light in hopes of an insect meal, and will otherwise delight you with their comings and goings.

We know little about the movements of adult amphibians, but it does seem that American toads are usually found within a limited home range, so one can become quite familiar with the individuals resident in a garden or similar area. An interesting article on the home ranges of American toads is posted at:
http://findarticles.com/p/articles/mi_qa3845/is_/ai_n17183721

The 60+ species of sea snakes – brightly colored, highly venomous relatives of the cobras, mambas and coral snakes – are little studied and not often seen in zoos.  I was fortunate enough to have worked with yellow-bellied sea snakes (Pelamis platurus) at the Bronx Zoo, but the species is no longer exhibited there (perhaps something to do with the preferred diet of live moray and American eels?).   If you have the opportunity to visit a zoo that keeps sea snakes, by all means do so – you will not be disappointed.

How Marine Snakes Find Fresh Water

A recent Physiological and Biochemical Zoology article, written by noted herpetologist Harvey Lillywhite, dispels a popular belief concerning marine snakes.   Sea snakes, it seems, do not use special glands to extract salt from sea water, thus rendering it drinkable.  These glands remove excess salt from the bloodstream, but the snakes can drink only fresh or very dilute sea water.

Research focusing on the black-banded sea krait (Laticauda semifasciata) showed that the snakes obtain all their drinking water from fresh water springs (sea kraits leave the water on occasion), and refuse to drink sea water even when dehydrated.  The majority of other sea snakes, which do not travel overland, are presumed to drink from the surface layer of fresh water that develops on the ocean when it rains.  Indeed, sea snakes reach their greatest diversity in regions with heavy rainfall, and sea kraits are most common near fresh water spring outflows.

Notes on Marine Reptiles in North America

The study seems to raise questions as to the drinking habits of other marine reptiles, such as sea turtles.  It brought to my mind time spent observing mangrove salt marsh snakes (Nerodia clarkii compressicauda) in Florida – that particular snake lives largely in salt water, but periodically travels to nearby fresh water swamps to drink.

At the mouth of the Nissequogue River on Long Island, NY, I encountered a population of snapping turtles (Chelydra serpentina) that have been documented as having salt-excreting glands not possessed by snapping turtles living further upstream in the same river.  I’ll soon review an article written on the turtles in that habitat, with a view towards reconciling it with this surprising new information.

You can read more about the natural history of sea snakes and sea kraits at the web site of the Chicago Field Museum:

http://www.fieldmuseum.org/aquaticsnakes/true_sea.html

Image referenced at Wikipedia, http://en.wikipedia.org/wiki/Image:Banded_Sea_Snake-jonhanson.jpg, and originally posted by Jon Hanson on FlickR.

Last time I reported on the Staten Islands Zoo’s use of the Zoo Med 10.0 High Output UVB Lamp (Please see Part I of this article). Today I’d like to provide some specifics concerning tests carried out there.

Test Results
The UVB output readings recorded at the Staten Island Zoo are as follows (note: measurements are expressed in microwatts per centimeter squared, the standard for measuring UVB output):

Zoo Med Reptisun 10.0 High Output UVB Lamp

Zoo Med Reptisun 5.0 UVB Lamp

As you can see, the basking site’s distance from the lamp has a major impact upon UVB exposure, as does the screen cover’s deflection of light rays. With a bit of creativity, basking spots within 6 inches of the lamp can be arranged in most situations, and this is certainly the way to go for many species. Where safe to do so, dispensing with the screen cover is another option.

Using a Separate Basking Enclosure
If a 6-inch basking site or uncovered top are not feasible in your pet’s terrarium, consider the possibility of utilizing a separate basking enclosure for a few hours each day. When keeping young radiated and star tortoises in high-topped zoo exhibits, where adequate UVB exposure was not possible, I rotated the animals into a low, uncovered container every day or so, and achieved excellent results.

If you go this route, be sure to keep your pet’s individual needs and temperament in mind. For example, a simple, open container that might suit a Greek tortoise would likely cause a good deal stress to a flat-rock lizard. High strung or secretive animals must be made to feel secure in the basking enclosure, or you may do more harm than good.

Reflectors and UVB Output
The group UV Guide UK has found that simply mounting the lamp within a metal reflector nearly doubles the UVB light that is available to basking animals. In addition to focusing all of the lamp’s light into the terrarium, I imagine that the reflector also helps by deflecting back some of the light that has bounced off screen tops or other structures.

An informative article on the role of UVB and basking behavior in Vitamin D synthesis is posted at:
http://www.uvguide.co.uk/vitdpathway.htm