The USA’s Only Native Rear-Fanged Vine Snake: Care and Natural History

Mexican Vine Snake

Uploaded to Wikipedia Commons by berichard

Although I’ve cared for Latin American and Asian vine snakes in zoos, and have searched their natural habitats, I had somehow missed the fact that one occurs in my own country, the USA. In extreme south-central Arizona may be found a “tropical-looking” snake seems somewhat out-of-place (to me, at least!) – the Mexican or Brown Vine Snake (Oxybelis aeneus). Being rear-fanged, high strung and quite demanding as to its diet, the Mexican Vine Snake is not recommended for other than well-experienced keepers. However, in both behavior and appearance it is most fascinating, and well-worth more interest and study.



Range and Habitat

Habitat type

Uploaded to Wikipedia Commons by Sergio Sertão

 As mentioned, the Mexican Vine Snake is unique among similar species in that its range extends into the USA…but just barely. The US population is limited to the Atascosa, Patagonia and Pajarito Mountains in the south-central tip of Arizona. The remainder of its range is huge, extending from Mexico to Brazil, Peru, and Bolivia, and including the islands of Margarita, Trinidad and Tobago.

The Mexican Vine Snake inhabits relatively arid environments, including dry forest edges, overgrown thickets, wooded grasslands, brushy hillsides and densely-vegetated canyons. In common with the other 3 species in the genus, it is entirely arboreal.

Size and Coloration

Mexican Vine Snakes are very thin and “vine-like” in profile (no surprises there!). Although somberly-colored, their various shades of gray, silver and copper blend together in an attractive manner. A dark line extends from the snout through the eye and down the neck. The chin and area below the eyes are usually bright yellow in color. Typical adults measure 4 1/2 – 5 feet in length.

The Mexican Vine Snake is a rear-fanged species that uses venom to kill its prey (please see below).

Green Vine Snake, Oxybelisfulgidus

Uploaded to Wikipedia Commons by Dimitri Eggenberger.

Also included in the genus Oxybelis are three other Latin American species, the Green Vine Snake (please see photo), Cope’s Vine Snake, and Roatan Vine Snake.

The Terrarium

Mexican Vine Snakes are best housed in large, vertically-oriented terrariums or custom-built cages. Zoo Med’s Repti-Breeze cage would be a good choice for a moderately-sized individual, but a large adult would require more room.

Climbing space is essential. The enclosure should be provided with numerous branches and tangles of real or artificial vines. Ideally, their living quarters should also be stocked with live plants, which will provide a sense of security and hiding spots. Hanging potted pothos has worked well for me. Most individuals prefer sheltering among plants and vines to hollow cork bark or other arboreal caves. If live plants are not used, hanging artificial plants and dry Spanish moss may be substituted. Mexican Vine Snakes will not thrive in small enclosures, or if denied above-ground cover.

t255908Like many arboreal snakes, Mexican Vine Snakes will drink water sprayed onto the body; some will also accept water from a bowl. As they do not take well to disturbances, cypress mulch or similar materials that allow for spot-cleaning are preferable to newspapers as a substrate. The cage should be located in a quiet area of the home. An ambient temperature range of 75- 80 F is ideal, with a basking site set at 88 F.

Some keepers believe that low levels of UVB light and UVA exposure are beneficial to this and related species.

Asian Green Vine Snake consuming frog

Uploaded to Wikipedia Commons by L. Shyamal


The natural diet is comprised of lizards, treefrogs and small birds; small arboreal rodents and insects may also be taken, but detailed field studies are lacking. Brown Anoles, Mediterranean Geckos and several other small lizards that have been introduced to Florida are the most reliably-available captive foods (in my experience, anoles were favored over others). Chicks and pink or fuzzy mice are taken by some individuals. The use of large food items has been linked to intestinal blockages, and I’m not certain that a rodent-only diet would be ideal long-term.

Youngsters feed primarily upon frogs and lizards, and usually refuse all else. Scenting a pink mouse leg with a frog or anole may induce feeding.

Care Notes

Waste must be removed in a manner that does not disturb the snake or expose one to a bite. The cage should be misted lightly each day, but dry conditions should prevail. As individuals offered for sale will likely be wild-caught, a veterinary exam is recommended for all new additions to your collection.


Captive breeding has rarely been accomplished, and is not well-documented in the literature. Research into this area by private keepers would be most valuable to this snake and its relatives. Field observations indicate that 4-8 eggs are typically produced.

Green Vine Snake Threat Display

Uploaded to Wikipedia Commons by Jayendra Chiplunkar


Mexican Vine Snakes are notoriously high-strung, and should be viewed as creatures to observe rather than handle. When approached, they open the mouth to expose its black interior and strike repeatedly (please see photo of Asian Green Vine Snake threat display).

Although the venom produced is not considered dangerous to people, the possibility of an allergic reaction, and the consequences of a bite to a child, elderly person, or immune-compromised individual, must be considered. Your doctor should be consulted before a rear-fanged snake of any species is acquired.

Blunt Headed Treesnake

Uploaded to Wikipedia Commons by Geoff Gallice

Other Vine Snakes

Asian snakes of the genus Ahaetulla also go by the common name of “vine snake”. Although they closely resemble the New World species in form and habits, they do not appear to be closely related. Several are available in the trade from time to time. I’ve kept the strikingly-beautiful Green or Long-Nose Asian Vine Snake (Ahaetulla nasuta; please see photos) at the Bronx Zoo – the experience was well-worth the time and energy invested in its care! Please post below for further information.

The Cloudy Snail-Eating Snake, Blunt-Headed Treesnake (please see photo) and 1-2 others of the genus Imantodes sometimes appear in the pet trade under various “vine snake” names as well.


Further Reading

Rough and Smooth Green Snake Care

Keeping Snakes in Planted Terrariums

Choosing the Best Turtle Filters: 10 Vital Points

Red Eared Sliders

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Red Eared Sliders and other semi-aquatic and aquatic turtles have just about everything one could ask for in a reptile pet – fascinating behaviors, responsiveness, breeding potential, beautiful coloration and shell patterns and with proper care, the ability to outlive scores of dogs and other “lesser beasts”.   But however how much we may enjoy them (and I know folks with collections numbering 100 to 2,000+!), keeping their water clean, both for clarity and health reasons, can be a frustrating and time consuming task. Today I’ll review some useful points to consider when deciding upon a filter. Please post your own experiences, thoughts, and questions below.


mediaA Note on the Various Models

We turtle enthusiasts are fortunate to have available a huge array of different filters designed for use with turtles. But when you consider also the traditional fish filters that also suit turtles, the choices can be overwhelming. I favor the Zoo Med Turtle Clean (please see photo) for most species, but submersible models, basking site/filter combinations, hanging types and others are all useful in certain situations. Please post below for detailed information on your particular turtle and aquarium.


Ease of Maintenance

However well-intentioned we may be, filter media changes tend to be put-off if they take too much time and effort. This becomes ever more important as one’s turtle collection grows. If you think this may be a concern, consider filters that require mere seconds to maintain, such as the Tetra Whisper In-Tank Filter.



Spotted, Bog and other turtles adapted to slow-moving water bodies cannot abide strong currents in their aquarium; the same is true for hatchlings of nearly all species. An overly-powerful filter outflow can even be a source of stress to large Cooters and Map Turtles, many of which are good swimmers that inhabit large rivers.


Some filters, such as Zoo Med’s Turtle Clean and the Ovation Submersible, have spray bars that allow us to control the force and direction of the filter’s output. Rocks and other objects may be used to modify the outflow of other models.



Soft-shelled Turtles, young Common Snappers, Reeves Turtles and many others fare best when kept at a water depth that allows the head to break the surface without the need for swimming. Filters designed primarily for use with fish generally do not function in partially-filled aquariums. Fortunately, most hanging, canister, and submersible turtle filters will work in shallow water…as low as 2 inches in some cases.


Water Changes

Bear in mind that regular partial water changes will be necessary, even with powerful filters. In easily-serviced tanks, this fact has allowed me to use small, inexpensive filters which would not be sufficient if frequent water changes were difficult to carry-out.


Feed Outside of the Aquarium!

Removing your turtles from the aquarium for feeding is perhaps the most important step you can take towards easing both your own and the filter’s workload. Please see the article linked below for further information.


Indian Flap-shell Turtle

Uploaded to Wikipedia Commons by Adityamadhav83

Eliminate Substrate Where Possible

Gravel and river rocks will add to the difficulties involved in keeping your water clear; impactions from swallowed substrate are also a concern. Chinese and other Softshells do best when a sandy substrate is provided, but most others can be kept in bare-bottomed aquariums. Regularly sweeping a brine shrimp net across the tank’s bottom will aid in maintaining water quality.


Consider Your Pet’s Size and Vigor

Turtles are very hard on filters, heaters and decorations, sometimes seeming to take a perverse pleasure in destroying our efforts on their behalf! Look into the size and power of suction cups, and how intake tubes attach to hanging filters, before making your decision. Please post below if you need information on specific models.


Use the Largest Enclosure Possible

Fish keepers learned long ago that larger aquariums are “more forgiving” of water quality mistakes than are small tanks. While there are many variables, the same holds true for turtles. Even if you keep small species, always provide them with as much space as is feasible. You’ll be able to use a more powerful filter, and water changes may be less critical…plus, you’ll improve your turtle’s quality of life and be treated to a variety of interesting observations.


Backyard pond

Uploaded to Wikipedia Commons by Tomwsulcer

Consider Outdoor Ponds

If weather and space (and finances!) permit, koi and goldfish ponds and filters are wonderful options. Nothing tops natural sunlight and an influx of insects in maintaining turtle health, and egg-deposition sites, almost impossible to include in aquariums, are easily arranged.



Further Reading

The Best Turtle Filters

Turtle Water Quality

Slider, Map and Painted Turtle Care

Frog Diets: Supplement Raises Poison Frog Egg Output & Tadpole Survival

Srawberry Poison Frog

Uploaded to Wikipedia Commons by Sarefo

Tulane University researchers have published an important study concerning captive frog nutrition that should be of interest to all amphibian and reptile keepers. A colony of Strawberry Poison Frogs (Oophaga pumilio) was maintained on a diet comprised of fruit flies. When carotenoids were added to the fruit fly diet, the frogs produced significantly more eggs, and a greater number of tadpoles survived through metamorphosis. The Vitamin A deficiency found among some of the animals was also reversed.


Nutritional deficiencies are common in both private and public amphibian collections, partly because of the limited dietary variety we are able to provide. Adding carotenoids (which are pigments produced by plants) to the diet of feeder insects may be a simple means of improving health and reproductive output – especially important in these times of unprecedented amphibian declines. Please see also the links under “Further Reading” for other articles I’ve written on supplementing cricket diets with carotenoids and Vitamin A deficiency in frogs.


Fruit Flies

Uploaded to Wikipedia Commons by TheAlphaWolf

Carotenoid Function and Sources

Various plant pigments known as carotenoids are responsible for the yellow-orange color of egg yolks and skin among a huge array of animals. They also play a role in neonatal health, benefit the immune system by acting as antioxidants and function in the reproductive system. Animals cannot manufacture carotenoids but rather must obtain them from their diet.


In the Tulane University study (Zoo Biology, V32, N6), the fruit fly medium’s carotenoid content was increased by the addition of Spirulina, red phaffia yeast and powdered marine algae. Studies have also shown that the provision of fruits and vegetables increases the carotenoid content of crickets; please see links below.


O. pumilio (Panama color phase)

Uploaded to Wikipedia Commons by Dendrotoine85

Effects on Reproduction and Survival

Sixty-two pairs of Strawberry Poison Frogs were included in the study. The increased tadpole survival was attributed to higher quality eggs being produced by female frogs. Infertile eggs, which are deposited by females as food for their tadpoles, were also believed to be of higher nutritional value following carotenoid supplementation.


A number of the animals were found to suffer from a Vitamin A deficiency. This condition was reversed over the course of the study. Many animals convert carotenoids to Vitamin A, so it is theorized that the addition of carotenoids to the fruit fly medium was responsible. As many frog enthusiasts know, the all-too-common condition known as “Short Tongue Syndrome” has been linked diets low in Vitamin A. If your frogs or toads are having difficulty catching insects, please see the link below, or post here for further information on this disorder.


Further Reading

Adding Carotenoids to Cricket Diets


Carotenoid Supplementation may Brighten Frog Colors


Do Your Frogs have Trouble Catching Insects?

Asian Leaf Turtle Care and Conservation: A Zookeeper’s Thoughts

Asian Leaf turtle

Uploaded to Wikipedia Commons by Wibowo Djatmiko

As part of my work for the Bronx Zoo’s reptile department, I once assisted in the rehabilitation and placement of nearly 10,000 Asian turtles confiscated from southern China and forwarded to Florida (please see article linked below). Included among the Spotted Pond Turtles, Painted Terrapins, Spiny Turtles were a great many Asian Leaf Turtles (Cyclemys dentata). This impressive turtle had been a great favorite of mine ever since we first crossed paths decades earlier, during my time working for NYC animal importers, and later on in zoo collections. Like many Southeast Asian turtles, this species is in severe decline, and has been extirpated from large portions of its range. Fortunately, Asian Leaf Turtles fare well in the hands of experienced owners. Those interested in turtle conservation can find no more worthwhile species to work with…and, as a bonus, they are extremely interesting and responsive!


Range and Habitat

The Asian Leaf Turtle’s range extends from eastern India south and east through Myanmar, Thailand and Malaysia to the Philippines. Although the range is large, local extinctions are commonplace. Collection for the food and medicinal trades has devastated wild populations, so please be sure to purchase only captive-bred individuals.


Habitat type

Uploaded to Wikipedia Commons by Marshman

It is found along shallow streams, ponds and marshy areas, and in nearby thickets. Youngsters spend most of their time in water, while adults forage on land as well.


The carapace, which is almost round in outline and somewhat domed, can be olive, tan, black, brown or deep mahogany in color; thin, reddish-orange stripes mark the head and neck. The edge of the carapace bears spine-like projections, which are much more distinct in juveniles than adults.


Adults average 8-10 inches in length.


Captive Temperament

Although initially shy, Asian Leaf Turtles adjust to captivity quickly, and soon learn to feed from the hand. Most owners describe them as “amazingly-responsive,” and longevities in excess of 30 years have been recorded.


Males often harass females with mating attempts, and may stress or bite them in the process.  In addition, males cannot be kept together, as they will usually fight.



Uploaded to Wikipedia Commons by Wibowo Djatmiko

The Terrarium

Hatchlings are highly aquatic, but rather poor swimmers. The water in a hatchling’s aquarium should be of a depth that allows the turtle to breath at the surface without needing to swim, i.e. 1-2 inches. The aquarium should be equipped with an easily-accessed basking site, UVB bulb, water heater, filter, and floating plastic or live plants under which the shy youngsters can hide.


Bare-bottomed aquariums are preferable, as gravel greatly complicates cleaning.


Adults do best in custom-made enclosures that measure at least 3’ x 4’ in area; outdoor maintenance is ideal when weather permits. Plastic-based rabbit cages and cattle troughs can also be modified as turtle homes.


A pool of shallow water should occupy approximately half of the cage’s area. Suitable hiding spots are important to the well-being of pet turtles; these include deep substrates into which your turtles can burrow and commercial turtle huts.  Cypress bark and similar commercial products, or a mix of topsoil, peat and sphagnum moss, may be used as a substrate.


The ambient temperature should be maintained at 75-85 F, with a basking temperature of 90 F.



The Asian Leaf Turtle’s appetite knows no bounds…in the wild, fish, tadpoles, snails, carrion, insects, and fruit are all taken with equal relish. Pets should be offered a diet comprised largely of whole animals such as earthworms, snails, insects, crayfish, prawn, minnows, an occasional pre-killed pink mouse and a variety of fruits (figs are a special favorite). Goldfish should be used sparingly, if at all, as a steady goldfish diet has been linked to kidney and liver disorders in other turtles.


A high quality commercial turtle chow can comprise up to 50% of the diet. I prefer Zoo Med’s turtle diets for this and similar species.


The calcium requirements of Asian Leaf Turtles, especially growing youngsters and gravid females, are quite high. All foods (other fish and pellets) should be powdered with Repti-Calcium or another reptile calcium supplement. A cuttlebone may also be left in the cage. Vitamin/mineral supplements such as ReptiVit should be used 2-3 times weekly.


Juvenile showing serrated plastron

Uploaded to Wikipedia Commons by Wibowo Djatmiko

A Note Concerning Water Quality

Turtles are messy feeders, and quickly foul even well-filtered aquariums. Removing your pets to a plastic storage container for feeding will lessen the filter’s workload and help to maintain good water quality.


Partial water changes (i.e. 50 % weekly) are also very useful. Some folks find it easier to maintain Asian Leaf Turtles in plastic storage containers that can easily be emptied and rinsed.



During the breeding season, the plastron becomes somewhat flexible to allow for the passage of the 2-4 unusually-large eggs. Females sometimes have difficulty passing their eggs, especially if the diet lacks sufficient calcium.


Gravid females usually become restless and may refuse food. They should be removed to a large container (i.e. 5x the length and width of the turtle) provisioned with 6-8 inches of slightly moist soil and sand. Gravid females that do not nest should be seen by a veterinarian as egg retention always leads to a fatal infection (egg peritonitis). Two to five clutches may be produced each year. Oxytocin injections are usually effective in inducing egg deposition.



Further Reading

The Asian Turtle Crisis

Black-Breasted Leaf Turtle Care

Keeping the World’s Largest Tarantula: a Zoo Keeper’s Experiences

Adult Goliath tarantula

Uploaded to Wikipedia Commons by Sheri (Bellatrix on Flickr)

Over 30 years ago, a good friend and Bronx Zoo coworker amassed what was almost certainly the USA’s largest and most varied tarantula collection. He personally collected many of the spiders, and established several notable breeding firsts. Then as now, the massive Goliath Bird Eating Spider or Goliath Tarantula (Theraphosa blondi, then known as T. leblondi) topped the wish lists of zoos and advanced private keepers. I cared for my friend’s collection when he was studying Brown Tree Snakes in Guam. Although well-experienced in keeping large, aggressive spiders, birds, mammals and reptiles, caring for wild-caught Goliaths in the dark (I had promised not to disturb their day/night cycle) really put me to the test!


The huge females were ravenous, and far bolder at night than by day. They rushed at water being poured into bowls, and seemed to snatch dead pinkies before they hit the terrarium floor. I was hampered by the lack of a headlamp, working instead with a flashlight clamped between neck and shoulder. All went well until something jumped from the wall onto my arm, then to my chest. I froze, but was relieved to see that the “visitor” was the resident Tokay Gecko and not an irritated tarantula! Today we’ll look at the care of these fascinating but somewhat demanding spiders.


A Giant Among Giants

As invertebrate enthusiasts know, the Goliath Tarantula is the world’s largest spider. While the Giant Huntsman Spider (Heteropoda maxima) and one or two others may slightly top the Goliath’s near 12 inch leg span, none approach its bulk. One account lists a weight of 175 grams for a captive female…by comparison, the average house mouse (wild, not lab) tops out at 20-30 grams!


At present, the genus contains two other species, – T. apophysis, described from Venezuela in 1991, and T. sterni, described from Guyana in 2010. The Panama Red-Rumped Tarantula was included in Theraphosa for a time, but is now classified as Sericopelma rubronitens.


Grammostola species showing shed hairs

Uploaded to Wikipedia Commons by Sarefo

A Note Concerning Handling

While certain tarantula species may become relatively calm in captivity, they cannot be “tamed” and should never be trusted on bare skin – Ignore You Tube videos to the contrary, please! Goliath Tarantulas usually remain high strung, even when provided with ideal captive conditions. They are very quick to flick hairs and bite when a threat is perceived. I and several arachnologist friends have worked with tarantulas at home, in zoos, and in the field for 50+ years without being bitten…because we do not handle tarantulas!


If it becomes necessary to move a tarantula, do so by urging it into a plastic container with a long handled tongs. Wear goggles around New World species, as all can flick urticating hairs into the air when disturbed (please see photo of “bald patch” on a tarantula). A colleague of mine required cornea surgery to remove the hairs shed by a Mexican Red Knee Tarantula. Hairs remaining on hands, terrarium tops, and other surfaces are as dangerous as those recently shed by a spider.


Tarantula fangs (chelicerae)

Uploaded to Wikipedia Commons by HTO

All tarantulas are capable of delivering a painful bite. Human fatalities are unknown, but their venoms are relatively unstudied, and an allergic reaction is always possible. A doctor should be consulted immediately if a bite is suffered.


The Terrarium

Goliath Tarantulas are best kept in screen-covered aquariums.   “High” style tanks are ideal, as they spend most of their lives in deep burrows, and will be stressed if not provided with such (some individuals adapt to surface caves, but burrows are preferable). Be sure to use extra cage clips on the cover, as tarantulas can climb glass and are incredibly strong. A 20 gallon aquarium is adequate, but I (and, I presume, the spiders!) much prefer a tank of 30-40 gallons capacity.


A wide variety of live plants may be used, although the spider may disturb these until a burrow site is chosen, Earth Stars (Cryptanthus) and other tough, low-light species are ideal; please post below for further information.


Habitat type

Uploaded to Wikipedia Commons by Pedro Gutiérrez.


A mix of coconut husk, top soil, and peat moss works well with these rainforest natives. Add just enough water so that the substrate sticks together when squeezed…keeping it so will prevent burrow walls from caving-in. Sphagnum moss can be worked into the soil in order to improve its moisture-holding capacity. Some keepers have done well by using 4-5 inches of substrate, but I provide adults with 8-12 inches or more.


Wild tarantulas often excavate burrows (or take over those occupied by their last meal!) beneath fallen logs, tree stumps and other cover. Several of the burrowing species I’ve cared for have used turtle huts and similar structures as starting points for their burrows. These and other caves should also be available for use until the spider constructs its own retreat.


Some keepers bury cork bark rolls with one edge facing the terrarium glass, and construct a tunnel that leads to the surface. In this way, the spider can sometimes be observed within its burrow. Please post below for further information.


Light and Heat

Red or black reptile night-viewing bulbs will not disturb your spiders and will assist you in observing their nocturnal activities.


Goliath Tarantulas are native to northern South America’s hot, humid rainforests and riverside thickets. They should be maintained at a temperature gradient of 80-86 F. Night-viewing bulbs, sub-tank heat mats and/or ceramic heater emitters can be used to warm the terrarium. All heat sources will dry out the terrarium, so it is important to monitor humidity.



Proper humidity levels are critical to good health, normal activity, and successful shedding (becoming stuck in a molt is a leading cause of death among captive Goliath Tarantulas). This tropical forest native requires humidity levels in the range of 75-85%. A hygrometer (humidity monitor) is an essential piece of equipment for the serious tarantula keeper. In dry environments, a small mister should be considered.

Just before and during the molt (please post below for further details re molting) humidity can be increased by partially covering the terrarium’s lid with plastic. As air flow is critical to good health, this option should only be used for limited periods.


Adult Goliath tarantula

Uploaded to Wikipedia Commons by Snakecollector

Food and Water

While some folks have had success with cricket-based diets, variety is preferable, especially if breeding is contemplated. I’ve done well by basing the Goliath diets on roaches and earthworms, with crickets being used less often. I also offer katydids, locusts, field crickets, moths and other wild-caught insects during the summer months, and notice that these often induce a very vigorous feeding response (please post below for more information on using wild-caught insects).


Although wild Goliath Tarantulas frequently ambush frogs, lizards and, perhaps, small rodents, a vertebrate-based diet is not recommended. Pre-killed pink mice can, however, be supplied every 2-4 weeks; some keepers believe this to be especially beneficial to breeding females. These voracious predators will readily accept dead prey moved about with a forceps or, in some cases, simply left in the terrarium; live mice should not be offered.


Incidentally, the “bird-eating” reference arose in 1705, when Swiss naturalist Maria Sibylla Merian included, in a book on the insects of Suriname, a painting of a Pink-Toed Tarantula consuming a hummingbird. The name she coined, “Bird-eating Spider”, remains in common usage today. While I’ve no doubt that a Goliath Tarantula would happily make a meal of any bird nestlings it might happen upon, this is likely a rare occurrence in the wild.


Canned grasshoppers and other invertebrates moved about with a long-handled forceps (remember, tarantulas have poor vision and may strike well above the food item – do not risk a bite!) can be used to provide occasional dietary variety.


Although spiders are able to obtain water from their prey, a shallow water bowl seems critical to success in keeping Goliath Tarantulas. The enclosure should also be misted daily.




Further Reading

Tarantula Care and Natural History

Beyond Webs: Swimming, Spitting and other Spider Hunting Strategies

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