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

Most herp enthusiasts know that amphibians are usually quite sensitive to warm temperatures.  However, reptiles, even those native to tropical and desert habitats, may be severely impacted as well.  Following are some general guidelines to keep in mind at the height of summer – please write in for more detailed information about the animals in your collection.

General Considerations

Even within the hottest of natural habitats, herps find ways to escape temperature extremes.  Millions of years of evolution have brought us a great many surprises in this regard – Australia’s Water Holding Frog, for example, thrives where most unprotected creatures, even reptiles, would cook in short order.  So while desert adapted animals may be better suited to withstand heat, do not assume that they will be fine without special attention. Read More »

Although they represent a mere 6% of the world’s snake diversity, boas, anacondas and pythons have long monopolized the attentions of herpetologists, private snake keepers, zoos and “non-herp people” alike. Much of our fascination centers upon the families’ giants, and the huge meals they consume. At least 2 species – the African Rock Python (Python sebae), and the Reticulated Python (P. reticulatus) – occasionally add people to their diet, and anecdotal evidence indicates that the same may be true of the Green Anaconda (Eunectes murinus). Captive Burmese Pythons (P. bivittatus), have on occasion killed caretakers, and the Indian Python (P. molurus) and Scrub Python (Morelia amethystinus) are certainly capable of doing the same. Even after a lifetime of working with giant constrictors, I was astonished by some of the anaconda meals (most notably a 60 lb. deer) that I was lucky enough to observe in the field.

 

Important Note: Green Anacondas and African Rock, Indian, Burmese and Scrub Pythons can exceed 20 feet in length, and cannot usually be properly and safely managed in private collections. Human predation, while rare, has been documented for several of these, and feral Burmese Pythons are causing ecological havoc in south Florida. As is the practice among professional zookeepers, at least 2 well-experienced adults should be on hand whenever constrictors exceeding 6 feet in length are fed or handled. Please see the article linked under “Further Reading” to read about a surprising study of human predation by Reticulated Pythons.

 

Classification

The world’s 40 python species are classified in the family Pythonidae and the super family Pythonoidae. Also included in Pythonoidae are the Mexican Burrowing Pythons (Lococemidae) and the Sunbeam Snakes (Xenopeltidae).

 

The world’s 58 boas (including the 4 anaconda species) are placed in the family Boidae. Boidae is further divided into 3 subfamilies – the True Boas and Anacondas (Boinae), the Sand Boas (Erycinae) and the Dwarf Boas (Ungaliophiinae).

 

Boas and pythons are considered to be “primitive” snakes, due to certain anatomical features such as vestigial pelvic girdles and rear limbs (the cloacal “spurs” seen on most species), but as you’ll see below they are extraordinarily successful. All are constrictors, and most are equipped with facial heat-sensing organs that allow them to locate warm-blooded prey at night.

 

Size

Pythons

At an adult size of less than 36 inches, Australia’s Pygmy Python (Antaresia perthensis), is the smallest species. At the other end of the scale, the Reticulated Python sometimes exceeds 20 feet in length. Also in the same general size category are Asia’s Indian and Burmese Pythons, the African Rock Python, and the Scrub Python of Australia.

 

A reward offered by the Bronx Zoo for a snake exceeding 30 feet in length remained uncollected for nearly 100 years. During my time working there, we were excited by photos of what looked to be a record-breaking Reticulated Python captured in Borneo. Upon arrival at the zoo, however, she proved to be “only” 21-23 feet long – but much stronger than the captive-bred specimens I’ve dealt with!

 

Boas

The various Dwarf Boas (Ungaliophiinae) are fully grown at 12-28 inches in length, while female Green Anacondas are the heaviest of all snakes and may equal or exceed the Reticulated Python in length.

 

Of nearly 500 Green Anacondas that I and co-workers tagged in Venezuela’s llanos region, a 17 foot-long, 215 lb. female proved largest; several others measured 15-16 feet in length. Reliable colleagues report sightings of larger individuals along forested rivers within the Amazon basin, but in such habitats they are nearly impossible to capture.

 

Range

Pythons

With a single exception (the Mexican Burrowing Python, Loxocemus bicolor), pythons are limited to the Eastern Hemisphere. Their greatest diversity is reached in Australia and New Guinea, but they are also well-represented in Africa and South/Southeast Asia. Feral populations of Burmese Pythons and African Rock Pythons are established in Florida, USA.

 

Boas

Boas occur nearly world-wide in tropical and subtropical environments, but are absent from Australia. They are represented in Europe by a single species, the Javelin Sand Boa (Eryx jaculatus). Many, myself included, are surprised to learn that the Rubber Boa (Charina bottae) ranges as far north as southern Canada. Boas reach their greatest diversity in Latin America, where they are sometimes the largest terrestrial predators in their habitats. Madagascar and several Caribbean and South Pacific islands are home to numerous endemic, and often rare, species.

 

 

Habitat

Boas and pythons occupy nearly every conceivable habitat, including deserts, rainforests, major cities, farms, arid woodlands, swamps, cloud forests, sand dunes, grasslands, large rivers, and many others. Some are highly specialized for life in the water, treetops, or below ground, while others, such as the Common Boa (Boa constrictor), are habitat generalists.

 

Reproduction

All pythons produce eggs which in most if not all species are incubated by the female. By contracting their muscles, or “shivering”, females can raise the temperature of their clutch by as much as 40 F.

 

With a single exception (the African Ground “Python”, Calabaria reinhardtii, formerly classified as a python), all boas and anacondas give birth to live young.

 

Diet

Many boas and pythons are generalists that consume a wide variety of mammals, birds, reptiles, and amphibians. For example, field studies show that the Common Boa takes tamanduas, green iguanas, raccoons, bats, monkeys, birds and a huge array of other creatures with equal gusto.

 

Specialists are also common. Mexico’s Oaxacan Dwarf Boa, an inhabitant of cool cloud forests, feeds primarily upon frogs, salamanders and their eggs, while the reptile-partial Black Headed and Woma Pythons include frilled lizards, bearded dragons and blue-tongued skinks in their diets

 

Mammals weighing in excess of 100 pounds, large crocodilians, turtles and other seemingly “unlikely” meals are taken by the giants of each group. Please see the article linked below for more on large, odd snake meals.

 

 

Further Reading

Reticulated Python Attacks

Odd and Giant Snake Meals

Anaconda Care and Natural History

 

 

The Indian Sand Boa (Eryx johnii johnii) is a “boa” in name only…in lifestyle and appearance it is in a class all its own. Being the largest and most docile of the world’s 12 sand boas, this fascinating snake is much sought after by reptile enthusiasts. Although no harder to maintain than the Kenyan Sand Boa and its other popularly-kept relatives, Indian Sand Boas are not commonly seen in the US pet trade, and rarely exhibited in zoos. Despite having spent a lifetime involved in reptile care in zoos and museums, I’ve only run across this attractive, interesting snake sporadically – hopefully more private keepers will begin working with it soon. Please let me know of any interest or experience you have had by posting below…you may also see this snake sold under the names “Red Sand Boa” and “Two-Headed Sand Boa”.

 

Description

To sand boa enthusiasts accustomed to the modestly-sized species typically seen in the pet trade, the Indian Sand Boa will seem impressively large and stout. The cylindrically-shaped adults average two feet in length, although some may reach nearly twice that size.

 

The small scales appear “polished”, and are colored reddish-brown or yellow-tinged tan. Certain individuals exhibit very beautiful hues of these colors, but all are attractive. The blunt tail closely resembles the head… when threatened, the Indian Sand Boa tucks its head into a protective ball of coils and presents the tail to its attacker. As an adaptation to life spent below ground, the wedge shaped head serves as a “spade”.

 

Range and Habitat

The Indian Sand Boa’s range has not been well-studied, but it is known to occur in western and southern India, Pakistan, Afghanistan and, possibly, Nepal. A subspecies, the Persiche Sand Boa (E. j. persicus), is limited in range to Iran. Eleven related sand boa species are found in Africa, south Asia and the Middle East.

 

Arid, scrub-studded plains, semi-deserts, and rocky hillsides are the Indian Sand Boa’s preferred habitats. Life is spent below-ground, usually just beneath the surface, with the head partially exposed.

 

The Terrarium

A single adult may be housed in a 20 to 30 gallon aquarium. Indian Sand Boas must be provided course sand and smooth gravel in which to burrow. These secretive snakes rarely thrive if forced to shelter in caves – rather, body contact with the substrate is essential. However, some will remain beneath a piece of glass laid atop and partially covered by sand, and so may be easily observed.

 

Heat

Indian Sand Boas do well at an ambient temperature range of 78-85 F, and with a basking temperature of 90-95 F. As they rarely bask on the surface, a sub-tank heat pad should also be employed along with an incandescent bulb.

General Care

In common with other snakes hailing from arid habitats, the Indian Sand Boa produces dry, compact waste products. If droppings are removed regularly, there is usually little need to break down and clean the entire terrarium.

 

As with the more commonly-kept Kenyan Sand Boa (please see photo), Indian Sand Boas must be kept dry, because skin and respiratory disorders develop rapidly in damp surroundings. Always use heavy water bowls that cannot be tipped over when the animal burrows. As other snakes are included in their diet, Indian Sand Boas are best housed alone, and should be watched carefully when paired for breeding.

 

Diet

Indian Sand Boas are highly-specialized ambush predators that wait below the sand for gerbils and other rodents, lizards and smaller snakes. To assist in this hunting strategy, the eyes and nostrils are placed high on the head, which is left partially exposed when they are hunting. Captives will literally explode from the sand to snatch mice moved about with a feeding tong…very impressive, and always a shock to the uninitiated!

 

The jaws of the Indian Sand Boa are not well-suited to swallowing large meals. Except for extra-large individuals, young mice are preferable to adults as a food source. Youngsters should be fed once weekly, while adults do fine with a meal each 10-14 days.

 

Breeding

A short period of increased humidity may encourage breeding, but seems not essential.

 

The young are born alive after a gestation period of approximately 4 months. Due to their large size (nearly 1/3 that of the mother) and unique coloration (orange with black rings) newborn Indian Sand Boas command high prices.

 

Unlike the young of other sand boas, they are large enough to take pinkies, and rarely “demand” lizards as food.

 

Temperament

While most other sand boa species become stressed when removed from their subterranean hideaways, Indian Sand Boas often take short periods of gentle handling in stride. However, the smooth, glossy scales may render them difficult to control.

 

All sand boas have an ingrained feeding response that often causes them to strike if touched while buried, so take care when approaching your pet or working in the terrarium.

 

Further Reading

Breeding Indian and Kenyan Sand Boas

Boa Overview: Care and Natural History

 

With its stunning coloration and reputation as a responsive pet, the Eastern Indigo Snake (Drymarchon corais couperi) is on the wish lists of serious snake keepers worldwide. I had the good fortune to assist with a breeding/release program headquartered at the Bronx Zoo, but federal and state regulations, and astronomical prices, hamper private ownership. However, an equally large and striking relative, the Blacktail Cribo (Drymarchon melanurus melanurus), is far easier to acquire as a pet. My first encounter with this impressive snake in the wild came while I was working with Green Turtles in Costa Rica. Streaking through the seaside scrub on a hot afternoon, the beautiful 6-7 foot serpent impressed me as few others have. From then on, I searched for them whenever I was within their range, and eventually sighted specimens in Mexico and northern Venezuela. Zoos and private keepers in the USA have not shown too much interest, but thankfully that is changing. Experienced snake keepers looking for an “Indigo alternative” will, I’m certain, be very happy with this fascinating snake.

 

Description

Robust and alert, the Blacktail Cribo averages 5-6 feet in length, but may approach or slightly exceed 8 feet. Most individuals are light to yellowish tan with a jet black tail and black markings on the neck, but there is a great deal of variation throughout their large range. Some are almost yellow, while others lack the black tail entirely. Breeders are focusing their attention on particularly-attractive specimens, and will likely develop distinct color strains in time.

 

Where their ranges overlap, hybridization occurs with the Western or Texas Indigo Snake (D. corais) and with a related Blacktail Cribo subspecies, D. m. erebennus (also sometimes referred to as the Texas Indigo Snake).

 

Range and Habitat

The Blacktail Cribo ranges throughout much of Mexico south through Central America to northern Venezuela, Columbia and Peru. It’s presence in El Salvador, Panama and Peru needs further confirmation. The northern subspecies, sometimes known as the Texas Indigo Snake (D. m. erebennus), is found from southern Texas to Guatemala and Belize.

 

The Blacktail Cribo is less demanding in its habitat requirements than is its highly endangered cousin, the Eastern Indigo Snake. It tolerates some disturbance, and may colonize farms, the outskirts of small towns and cattle ranches. When I worked in Venezuela’s llanos country, ranchers reported that Blacktail Cribos were sometimes seen near storage sheds and outbuildings. Chicken coops were not common in the area, but I’m guessing they would be a favored stop-off for these ever-hungry brutes as well! Natural habitats include thorn scrub, brushy areas within the llanos, open woodlands, desert fringes and swamps.

 

Blacktail Cribos actively search for their prey, which includes a surprisingly-wide array of creatures. Rodents, rabbits, snakes, birds and their eggs, lizards, frogs, fish, small turtles are large insects have been reported as being taken. I have first-hand experience with impressive biting power packed by most rodents, and find it amazing that Cribos do not utilize constriction, but merely grab and swallow their victims!

 

Blacktail Cribos as Pets

In common with the Eastern Indigo Snake (please see photo), wild caught or un-habituated individuals may make a show of flattening their heads, hissing and vibrating the tail when approached. However, with care and attention, most calm down. In fact, many consider them to be among the gentlest of the larger Colubrids, on par with captive reared Eastern Indigo Snakes.

 

Alert and quite aware of their surroundings, Blacktail Cribos seem much more responsive than is typical of snakes in general. However, they tend to move about when held, and can be difficult to control. Bites may occur even where well-habituated pets are concerned, as hungry individuals will strike at nearby movements.

 

The Terrarium

Cribo ownership should not be entered into lightly. They are very active, and do poorly in cramped quarters. A typical adult requires a custom-built cage measuring at least 6 x 4 feet.

 

A dry shelter, and another stocked with moist sphagnum moss, should be

available.

Substrate

Cypress mulch, eucalyptus bark and similar materials may be used as substrates. In common with Indigo Snakes, Cribos produce copious, watery waste products at frequent intervals…near daily cleaning is often necessary. Keepers weaned on Ball Pythons and similar snakes will be in for quite a surprise! Enclosures should be cleaned regularly with a reptile-safe product or diluted bleach or Nolvosan.

 

Due to this snake’s vigorous movements, newspaper tends to wind up crumpled in a corner. Washable terrarium liners be used for younger animals kept in aquariums.

 

Heat and Light

Blacktail Cribos favor cooler temperatures than might be expected, and fare best at a range of 70-78 F. An incandescent bulb should be used to create a basking spot of 85 F.

 

Large enclosures are necessary if a thermal gradient (areas of different temperatures) is to be established. Thermal gradients, critical to good health, allow snakes to regulate their body temperature by moving from hot to cooler areas.

 

A ceramic heater, heat pad, or red/black reptile night bulb can be used to provide heat after dark.

 

Feeding

As mentioned above, Cribos will eat nearly any animal that can be overpowered. Captives do fine on a straight rodent diet, but some private and professional keepers advise providing more variety. I favor this approach on general principles and because, unlike many other snakes, Cribos tend not to become “fixated” on one food item as opposed to others. Chicks, shiners, trout, eggs, and any pet trade rodents you may wish to offer will all likely be accepted.

 

Blacktail Cribos should be offered smaller meals than might be accepted by similarly-sized snakes of other species, as their jaws do not stretch to the same extent. Small to medium rats are about the largest food item that should be offered to adults. They have fast metabolisms, and may need to be fed a bit more frequently than each 7-10 days.

 

The 18-24 inch-long hatchlings may prefer fish scented rodents at first, but are easily weaned onto unscented mice in time.

 

Water for drinking and soaking should be available. Bowls are best filled to a point where they will not overflow when the snake curls up within, as damp conditions will lead to fungal infections of the skin and other health problems.

 

Breeding

Captive breeding successes are increasing, but as with Eastern Indigo Snakes consistent results have been elusive. Pairs must be monitored carefully, as males may bite females during courtship. Please post below for further information, or to share your own experiences.

 

Further Reading

Indigo Snake Care

Tiger Ratsnake Care

North America’s Hognose Snakes are well-known for their impressive defensive displays. I’ve found the Eastern Hognose in its natural habitat and have bred it for a release program during my tenure at the Bronx Zoo. But as this snake limits its diet to toads, it is rarely seen in zoos or private collections. The Western Hognose Snake (Heterodon nasicus), on the other hand, has gained a following among snake-keepers that is usually reserved for rat snakes, boas, and pythons. It seems to be the most popular of the “non-typical” snakes kept, at least here in the USA. Reasons for this abound, including a “viper-like” appearance, dramatic defensive display, calm demeanor, non-demanding diet, and willingness to reproduce. Selective breeders have been thrilled with this species as well – as evidenced by the astonishing 52 “designer color morphs” that have been produced!

 

I’ve also had the good fortune to work with the very impressive Madagascan Giant Hognose Snake (Leioheterodon madagascariensis); please see the article linked below for further information.

 

Classification

Two snakes formerly considered to be subspecies of the Western Hognose Snake have now been described as full species – the Dusky Hognose (H. gloydi) and the Mexican Hognose (H. kennerlyi). Also included in the genus are the Eastern Hognose Snake and the Southern Hognose (H. platyrhinos, and H. simus, see photos).

 

Description

The Western Hognose Snake is heavily-built, yellowish-tan, gray, or dark brown in color, and marked with black blotches. Upturned rostral scales on the snout assist it in burrowing and unearthing prey. Adults average 2 feet in length, but appear larger due to the thickness of their bodies; the published record size is 35 ¼ inches.

 

I was surprised to find that the number of color morphs available now rivals those established for those two pet trade heavyweights, the Ball Python and Corn Snake. At least 52 color and pattern variations, with fanciful names such as Albino Super Anaconda, Coral, and Pistachio, are now being offered. You can see photos of many at the site linked below.

 

Range and Habitat

The Western Hognose Snake’s range extends from southeastern Alberta to northwestern Manitoba, Canada, and south to southeastern Arizona, Texas and northern Mexico; isolated populations may be found in Minnesota, Iowa, Illinois and Missouri.

 

Largely terrestrial and often sheltering below ground, the Western Hognose favors open habitats such as sandy or sand/gravel prairies, thorn scrub, and lightly wooded grasslands, and has been found to elevations of 8,000 feet above sea level.

 

Temperament in Captivity

Western Hognose Snakes are rear-fanged, and produce mild venom that is used to overcome their prey. They are not considered to be dangerous to people, but the consequences of allergic reactions or of a bite to a child, senior citizen or immune-compromised individual should be considered. Consult your doctor before acquiring any rear-fanged snake.

 

When cornered, the Western Hognose Snake flattens the body and hisses loudly, after which it strikes, usually with a closed mouth. When pressed further, it may roll over and feign death. Captives soon give up this charade, which in any case is rarely as dramatic as that put on the Eastern Hognose.

 

Many people see a close resemblance between this snake and the several rattlesnake species that share its range. As you can see from the photo, a similar appearance and display is seen in other Viperids as well, such as Africa’s Puff Adder.

 

The Terrarium

Youngsters may be accommodated in 10 gallon aquariums. Average-sized adults can be kept in a 20 gallon long-style aquarium, with a 30 gallon being preferable for extra-large individuals or pairs. The tank’s screen lid must be secured by cage clips, as they are very powerful, even by snake standards.

 

Natural burrowers, Western Hognose Snakes are most comfortable below-ground. A deep layer of cypress mulch or aspen is preferable to newspapers as a substrate. I’ve kept Eastern Hognose Snakes on a sand/gravel mix, but the possibility of impactions has been raised by some keepers; please post below for further information.

 

Native to arid environments, Western Hognose Snakes do not fare well in damp enclosures.

 

Heat and Light

Western Hognose Snakes do well at a temperature gradient of 75-82 F. An incandescent bulb or sub-tank heat pad should be used to create a basking spot of 90 F.

 

A ceramic heater, heat pad, or red/black reptile night bulb can be employed to provide heat after dark.

 

Diet

Not nearly as picky as its east coast cousin, the Western Hognose takes toads, lizards, other snakes, rodents and the eggs of turtles, lizards, and birds with equal gusto.; locusts and other large invertebrates have also been reported as food items.  I recall one study in which this species was identified as the major nest predator of an endangered turtle (the details escape me right now).

 

Captive adults readily accept mice, but hatchlings prefer lizard or toad-scented pink mice at first (some keepers report that water from canned tuna also works well). In time, they can be weaned onto unscented mice.

 

Breeding

In their natural habitat, Western Hognose Snakes breed from March-May, and females deposit 4-25 eggs approximately 3 months later. The 6-7.5 inch long youngsters hatch in 7-9 weeks, and are sexually mature at 2-3 years of age. The published longevity for this species is just short of 20 years.

 

Pets are not so closely tied to the seasons as are wild individuals. Please post below for detailed information on captive breeding.

 

 Further Reading

Madagascar Giant Hognose Snake Care

Western Hognose Color Morphs