by Roy Arthur Blodgett
Disclaimer
It is important to begin by disclosing that what follows is largely a work of opinion, primarily informed by the author’s experiences and secondarily by those of other keepers who have generously shared their successes and failures. As with all endeavors, there are many ways of achieving success working with animals in captivity – and just as many ways of determining what qualifies as success. Herpetoculture at its best is not prescriptive, but rather attentive and responsive. As such, what I’ve written here is a living document and is sure to adapt and change with continued learning and observation of the animals in my care. I want to be clear that I don’t claim to know the best way, and I have no intention of offering the only way. My aim herein is simply to offer what I have observed and what has worked for me, backed by the best evidence I can find, with the driving intention of exploring how to provide the quality of care and attention which I feel all captive animals profoundly deserve.
The keeping of animals in captivity is a complicated and often paradoxical prospect, and something that I do not expect to entirely reconcile. One thing to me is clear, though: if I am to be responsible for the well being of a life which is not my own, then I intend to undertake that responsibility with as much care and sensitivity as I can muster. In my journey with herpetoculture, the privilege of this undertaking and arrangement has come with an ample share of gratitude, and has been punctuated at times with regret at mistakes I have made. My primary commitment is to continue learning from both ends of that spectrum and to continue progressing as a keeper.
Introduction and Natural History
Xenodon pulcher, commonly known as the tricolor or banded hognose snake, is a small, fossorial dipsadid snake native to the Gran Chaco region of the South American continent. Mature adults of the species measure 24 to 30 inches in length on average, and are distinctly clad in smooth scales patterned in red (or orange), black, and white (or yellow) bands. Aberrancy in pattern is not uncommon and bicolor specimens lacking red or white are occasionally encountered. The species is easily identified and differentiated from other tricolor snakes with which it is sympatric by its distinctive upturned rostral scale, an adaptation which aids in the subterranean behavior for which this snake and its relatives are known. The tricolor hognose snake, like other nonvenomous tricolor snakes in its range, is thought to mimic the highly venomous coral snake (Micrurus pyrrhocryptus).
Widespread in their native range, tricolor hognose snakes are strongly associated with the Chaco bioregion, from eastern Bolivia, southern Paraguay, and southwestern Brazil in the north, south through central Argentina. This region has a relatively mild, temperate climate, with average daytime highs in the mid-80s F dropping into the mid-60s F at night through the warmer months.
Winter temperatures average with daytime highs in the mid-60s F and nighttime lows in the mid-40s F. Rainfall begins in spring and peaks in the summer months, while the winters remain relatively dry. Photoperiod peaks at approximately 14 hours in the summer months, and gradually reduces to 10 hours of sunlight in the depths of winter. These patterns drastically influence the activity patterns of Xenodon pulcher, with a strong spike in observations of the species occurring in the spring, corresponding with the onset of heavy rain and increased amphibian activity.
Often described as psammophilous (having a preference for sand), Xenodon pulcher is a denizen of grassland, savannah, shrubland, and occasionally woodland habitats with sandy soils, where it preys primarily upon amphibians, lizards, and squamate eggs. The species is opisthoglyphous, possessing enlarged rear fangs and venom which aids in immobilizing prey. Though there are no confirmed human fatalities attributed to them, envenomations have been documented on occasion by captive keepers who have reported mild symptoms including swelling, edema, and nausea, subsiding within hours to days after the bite. Usually such bites are related to a feeding response and the species is not inclined to bite defensively in my experience, but will occasionally resort to a defensive display of dorsal flattening, bluff striking, and fast, erratic movements intended to dissuade potential predators or other threats – interestingly, such behaviors are also common in coral snakes.
Housing
Given their modest size, tricolor hognose snakes can be suitably housed in a number of different styles of enclosure – from glass tanks, to wooden enclosures, to modern PVC setups. I recommend housing adults individually (except for breeding purposes) in enclosures of approximate dimensions of 36” by 18” by 18” (or larger, if possible), with a substrate depth of at least 3 inches to adequately allow for burrowing behavior. Due to their activity level, these snakes will make use of whatever space they are afforded, and despite common claims that they hide all the time, I have found that when given the opportunity to express natural behaviors such as basking and climbing, they will not hesitate to do so.
Given their fossorial nature, substrate is an important component in the care of tricolor hognose snakes. A number of options are commercially available and suitable for the burrowing needs of the species, and keepers have successfully used materials as disparate as aspen bedding and coconut coir fiber. Substrates with very fine clay or dust particles should be avoided, as such fine materials are prone to adhering to the snakes’ scales, particularly around the eyes and nostrils. For substrates that don’t retain humidity well, it is recommended to provide a humid hide filled with a moisture retaining material such as long fiber sphagnum moss. For the snakes in my care, I try to emulate their native soil as well as I can, and provide a mixture of play sand, peat moss, decomposed granite, and leaf litter, which allows for extensive burrowing without fine particles adhering to the snakes’ scales.
This mixture also finely accommodates the needs of live grasses native to the Gran Chaco which I have included in the vivariums of my tricolors for cover, and is suitable for microfauna such as springtails and isopods, which can be employed to assist in vivarium maintenance as a clean up crew to consume residual waste that is missed from spot cleaning. To provide a moisture gradient in the substrate, I occasionally overfill the water bowl that I provide the snakes for drinking water, which is kept on the opposite end of the enclosure as the heat elements. This provides a wide gradient in moisture levels in the substrate, with the cool end remaining quite cool and moist, while the warm end stays dry.
Vivarium decor, such as rocks and branches, provides cover and can be used to improve opportunities for the snakes to perform natural behaviors. I have found that tricolors will readily climb if provided the opportunity in the form of branches or other structures. Rocks provide hiding opportunities, and, when used in conjunction with overhead heat sources emitting IR-A and IR-B, also retain heat in the form of thermal mass, which the snakes will readily utilize for thermoregulation. Cover in the form of leaf litter and live or artificial plants is also beneficial, providing security and allowing for behaviors such as cryptic basking, in which a snake might bask with only part of its body exposed. Witnessing such behaviors emerge in a captive setting is a consistently gratifying experience for me as a keeper.
Heating and Lighting
When I first began keeping tricolor hognose snakes, I kept them as most keepers do, using under tank heat tape as the primary source of infrared, with ambient lighting providing a photoperiod. However, after learning more in recent years about the spectrum of infrared radiation, I’ve moved away from viewing such methods as adequate sources of long term heat, and have instead moved to prioritize overhead heating and lighting, as I do with all of my other reptiles. To achieve this, I use PAR38 halogen bulbs, which emit infrared radiation rich in IR-A and IR-B wavelengths, and supplementally provide IR-C by heating rocks and other enclosure decor. Since making this transition, I have frequently observed the snakes in my care exhibit a broad range of basking behavior – from burying themselves in the substrate just below the beam of light, to basking openly on branches just below the lamp. In terms of temperatures, surfaces within the wide beam of the lamp can reach the mid-90s F, while ambients on the warmer side of the enclosure average in the low to mid-80s F, gradually decreasing to the low 70s F on the cool end. I don’t provide supplemental nighttime heat, and nighttime temperatures drop on average into the mid-60s during the summer months, and cooler in the winter.
For lighting, I use a combination of LEDs, for visual light and optimal plant growth, and T5HO UVB bulbs for all the added health benefits that such bulbs provide. I aim to maintain a UVI gradient of 1.5 – 3.5, with the highest UVB readings at the basking area nearest the bulb. This combination of LEDs, T5HO bulbs, and halogens also recreates a photoperiod for the snakes, with the halogens dimming on and off each morning and night to simulate sunrise and sunset. After the halogens have reached full brightness, they are followed by the LEDs, which are followed by the T5HO bulbs at the peak light intensity of the day. I adjust the timing of the bulbs on a biweekly basis to reproduce the seasonal change in photoperiod which the snakes would experience in their native range, and because the halogens are their primary source of heat, this also helps to reproduce the changes in seasonal temperatures. These rhythms are also key elements to successfully breeding this species.
Diet and Nutrition
Within their native range, tricolor hognose snakes and their relatives feed primarily on amphibians, lizards, and squamate eggs. In the scant literature I’ve been able to find describing the diet of the species and its relatives, there has been no recorded evidence of mammalian prey. Despite this, and largely out of convenience, the vast majority of reptile keepers and breeders working with tricolors have fed the species a diet primarily consisting of rodents, which they will often eagerly accept as prey. I have my doubts that this is a sustainable diet for them, though, as I’ve encountered numerous accounts of early death in the species from fatty liver disease – an ailment which in herpetofauna is usually correlated to feeding animals too rich a diet. This is also likely due in part to feeding the species too frequently, particularly as adults.
Accordingly, I prefer to feed the adult pulcher in my care a primarily non-rodent diet consisting of small quail and cased links composed of ground (whole-prey) frog and/or lizard. I also aim to keep the adult specimens in my care quite lean, avoiding an overweight body condition often expressed by obvious scale separation. This usually corresponds to feeding the adults in my care every 10 – 14 days during their active seasons, and it is not uncommon for my adult male to refuse food for weeks at a time, thereby setting his own feeding schedule to some degree. For adult snakes that have been on rodents, which don’t at first accept links or quail as prey, I have found that chain feeding is a helpful method for encouraging them to switch. This method involves offering the snake a prey item it is certain to accept, and while it is swallowing that prey item, sneaking in the second prey item as the snake moves its jaws to consume the first. In my experience, this only has to be performed once or twice before the snake will begin recognizing the second offering as prey and accepting it outright, usually with zeal. For neonates, I alternate offering extra small pinky mice and button quail heads on a weekly basis, both of which have been eagerly accepted in my experience when drop-fed overnight. As soon as juveniles are large enough to accept whole button quail, I offer them and cased links of frog and/or lizard exclusively, gradually increasing prey size as the snakes grow.
Most tricolors are ravenous feeders, but this is particularly true of female specimens in peak season which are prone to strike at almost anything that moves in hopes of securing a meal. This can be a precarious situation for the unsuspecting keeper who needs to change the water, do a bit of spot cleaning, or handle the snake for a brief inspection. To address this, I have taken to alerting the snakes of my presence by bumping them gently with a small snake hook before proceeding with vivarium maintenance. The snakes quickly associate this cue as being unrelated to feeding, and since employing this method, I’ve yet to suffer a single bite from my tricolors.
Brumation and Breeding
Xenodon pulcher, like most reptiles adapted to a temperate environment, is resigned to a period of relative inactivity and torpor in the depths of the winter months called brumation. This period is an important process in the life cycle of the species, key to normal spermatogenesis in male snakes and egg development in females. As such, for optimal breeding success, it must be reproduced for snakes in captivity. Achieving this is a relatively simple process of altering photoperiod and ambient temperatures, as has been alluded to already. In my circumstances, because I live in a temperate region and maintain my snakes in my basement (which has relatively stable year-round temperatures), it is only a matter of reducing the photoperiod I provide for my snakes in the winter months. As a result, their activity level decreases dramatically and they begin to show less interest in food (particularly in males), only occasionally emerging from the substrate to bask or drink from their water bowls. With increasing temperatures and day length in spring, I begin offering food regularly again, in anticipation of pairing the snakes in early summer.
Tricolor hognose snakes are vigorous breeders and pairings usually lead to copulation within a matter of minutes or hours, in my experience. The courtship process involves the male snake pursuing the female, riding across her back in undulating, serpentine motions, and tongue flicking intently, all while attempting to align himself and lift the females tail. If the female is receptive she will lift her tail, allowing the male access to the cloaca. Copulation itself lasts for up to four hours in my observations. If a female is unreceptive, she will flee the male’s advances and wrestle to avoid lifting her tail. In such cases I simply remove the male and try again after a few days. It’s important to supervise pairing and avoid cohabiting for longer than a day or two, as eager males can cause considerable stress on females with their amorous advances.
If copulation is ultimately successful, females will lay their first clutch of the season as soon as five weeks after mating, and if well fed, will continue to produce consecutive clutches every five to six weeks until photoperiod and temperatures begin to arc toward brumation. In my experience, the female will shed three to five days before oviposition. With my snakes clutch sizes have ranged between 5 and 9 eggs, but larger clutches are not uncommon. I opt for incubating the eggs at 78 F with a nightly drop to 76 F and humidity of 80%, which results in hatching approximately 105-110 days after oviposition. Warmer temperatures may result in shorter incubation times, but also correspond to smaller, less vigorous neonates. So far, I’ve had excellent results with incubating at these temperatures, with neonates hatching at an average weight of 5 grams, and accepting their first meals just a few days following their initial shed.
Conclusion
In my opinion, Xenodon pulcher is a fantastic species for the novice to intermediate herpetoculturist. The combination of their stunning beauty and modest size gives them excellent potential for average keepers and single-pet households, who might have too limited space or resources to commit to a larger species. They are also durable snakes, forgiving of most beginner mistakes – a fact that has unfortunately contributed to them enduring substandard husbandry practices in the mainstream. When kept with care and regard for their capacity to exhibit natural behaviors, they are rewarding and engaging snakes, which will hopefully continue to increase in popularity for years to come. There is still much to learn from this captivating little gem of the Gran Chaco.
Reference Materials and Recommended Reading
- Annual activity patterns of snakes from central Argentina (Cordoba province)
- Reptilia, Colubridae, Xenodontinae, Lystrophis dorbignyi, Lystrophis pulcher, and Lystrophis semicinctus: Distribution extension, new provinces records in Argentina
- Natural history of Xenodon matogrossensis (Scrocchi and Cruz, 1993) (Serpentes, Dipsadidae) in the Brazilian Pantanal
- Weatherspark: Cordoba, Argentina
- iNaturalist: Banded Hognose Snake (Xenodon pulcher)
