Polanco, Joseph M.

English

Biodiversity Informatics

IGUANA  •  VOLUME 13, NUMBER 2  •  JUNE 2006 133CORALLUS CANINUSWith the largest known range of any currently recognizedspecies of boid and a fascinating and beautiful variety ofmorphologies, one might logically assume that the Emerald TreeBoa (Corallus caninus) would be among the most recognizable andwidely kept species in herpetoculture. However, it is only recentlythat a broader understanding of the species has enabled prospec-tive keepers to adapt and develop the environmental regimes nec-essary for this highly specialized snake to thrive in captivity.The first installment (Iguana 13(1): 37–41) proposed a setof guidelines for the acquisition and preparation of enclosuresappropriate for housing the species. Part II presents one soundstrategy for the acquisition of healthy, viable specimens as wellas some of the more technical details associated with husbandry.INTRODUCTIONPreparation and forethought equal to that employed during theconceptualization, procurement, and setup of the enclosureshould now be addressed to acquiring a snake. One of the bestresources for today’s herpetoculturists is the internet. This inter-active knowledge base provides access to reams of information,anecdotal experiences, and live response forums linking newkeepers with those who have already had success with EmeraldTree Boas. Judicious use of the internet can help prospectivekeepers form realistic expectations, minimize the likelihood ofunpleasant surprises, and provide a generous sounding board forthose actively seeking answers to specific questions. Researchersinvolved primarily with species classification and the study ofnatural history have long benefited from the publication and dis-semination of scientific information. The information-sharingcapabilities of the internet have resulted in an exponentialincrease in interest and success for herpetoculturists involvedwith the captive husbandry of this and other species.SPECIMEN ACQUISITIONAs with habitat selection, personal taste and practical affordabil-ity are important factors during the selection of an animal. Theuninitiated often tend to overlook the subtleties that differenti-ate individuals within any given species. For C. caninus, this canH U S B A N D R YEmerald Gems (Corallus caninus): Captive Husbandry and PropagationPart II: Acquisition, Maintenance, and DietJoseph M. PolancoPhotographs by the author.Prospective purchase of an Emerald Treeboa (Corallus caninus) shouldonly be considered when the snake’s outward physical appearance con-forms to criteria established for robust, healthy animals.A healthy Emerald Treeboa (Corallus caninus) is robust, unblemished,brightly colored, and active, coiling tightly on elevated perches andresponding quickly to stimuli.Iguana 13.2 b&w text.QX6  6/26/06  1:20 PM  Page 133lead to an “all emeralds are more or less equal” mindset, whichmay place too much weight on the physical beauty of an indi-vidual specimen. This is one of the most common mistakes first-time keepers are likely to make. As with icebergs, within theCorallus complex, what lurks beneath the surface is what needsto be evaluated in order to make a wise decision. The tempera-ment and physical condition of animals available on the openmarket varies widely and individuals inexperienced with thespecies do not have the odds in their favor. Wild-caught animals,especially those that have not been in a stable, controlled envi-ronment for a minimum of one year, should never be consid-ered by any but the most seasoned of veterans.Acclimating wild-caught treeboas is no simple undertaking.Any reputable dealer, even those with years of experience, willtell you that the mortality rate of imported specimens of thisspecies is appallingly high. Statistics indicate that more than50% of captives of all ages die during the first year. For thosespecimens that do survive the initial acclimation period, chancesof survival in the long term (> three years) are equally grim.Although I have not been able to collect empirical data, my ownnumbers reflect a survival rate of just over 65% for adult tree-boas and just over 70% for animals acquired prior to their onto-genetic change.Therefore, as a rule, only captive-born and bred specimens(subsequently referred to as CBB), purchased from well-estab-lished, reputable sources should be considered. Where C. cani-nus is concerned, “impulse buying” more often than not leadsto an unfortunate experience. Morphological conformationnotwithstanding, prospective acquisitions should only be con-sidered if and when their outward physical appearance conformsto the criteria describing a robust, healthy animal. Animals thatappear skinny, dehydrated, blemished, dull, sluggish, or gaping,or those that are loosely coiled or not perched at all should bedismissed out of hand. For the purposes of this article I willrestrict all future references and recommendations to those appli-cable to CBB specimens.The above-mentioned physical conditions are often symp-tomatic of a variety of potentially serious pathologies. One ofthe few true challenges associated with this species is that eventhe most common ailments are often difficult to detect. Devoidof compassion or sympathy for the infirm, nature provides manyspecies, including C. caninus, with the instinct to mask illness.Emeralds are so adept at this practice that by the time a prob-lem becomes obvious the individual is often beyond salvage. Forthis reason, animals with a history of illness, however minor,should be dismissed from consideration.The previously mentioned statistics largely reflect the morecommonly available “Northern” variety of the species. Althoughsusceptible to the same maladies, stress-related illnesses, and par-asitic infestations, the Amazon Basin variety appears to benefitfrom two factors that may be largely responsible for the differ-ences seen between the two populations. First, the Basin form iswidely believed by those intimately familiar with both varietiesto be hardier and more resilient. Although this disparity itself isundocumented and remains largely unexplained, one popularbelief is that this form’s larger geographic distribution has pro-vided for an inherently wider set of environmental tolerances.The other more prosaic factor has been the lack of ready avail-ability of Basins to the export trade. Local restrictions and thelogistical challenges associated with their collection have kept theexported numbers of Basins very low for over three decades andthe prices charged for these rarely seen but highly prized exportshave tended to be very high. With the laws of supply anddemand keeping prices high, improved care at every stage of theimportation process provides better returns for importers.Currently, a relatively strong U.S. community of wellknown, reputable breeders is involved with the propagation andsale of both Northern and Basin varieties. On the whole, these134 IGUANA  •  VOLUME 13, NUMBER 2  •  JUNE 2006 POLANCOWild-caught animals, especially those that have not been in a stable,controlled environment for a minimum period of one full year, shouldnever be considered by any but the most seasoned of veterans. Thisindividual, although superficially healthy, was dead on arrival at thefacilities of a dealer in tropical reptiles.Blister disease can be debilitating; acquiring an animal with the intentof nursing it back to health is a bad idea, even for an experiencedkeeper.Iguana 13.2 b&w text.QX6  6/26/06  1:20 PM  Page 134IGUANA  •  VOLUME 13, NUMBER 2  •  JUNE 2006 135CORALLUS CANINUSindividuals happily offer support and guidance before, during,and sometimes after the sale. This type of networking acts as aninvaluable safety net for those interested in keeping this species.By availing themselves of the knowledge and experiences of oth-ers, prospective keepers are able to tip the scales steeply in theirfavor, drastically reducing the duration of the C. caninus learn-ing curve.Husbandry BasicsThe essentials of effectively keeping C. caninus in captivity canbe broken down into three categories: environment, diet, andrecord keeping. The first installment discussed the importanceof stabilizing environmental factors prior to the introduction ofa live animal. Although C. caninus is not an overly delicatespecies, keepers can be quickly overwhelmed with health issueswhen tolerances are violated.Until such time as accurate DNA-profiles of the speciesallow for a classification by which herpetologists can identify anddifferentiate individual populations, accurately fine-tuning indi-vidual environmental variables to specific animals remainsimpossible. Locality data on imported specimens are non-exis-tent, and morphological differentiation is far too imprecise toprovide even the most remote hope of accuracy. Therefore,today’s Emerald specialists have chosen to employ a range oftemperature and humidity standards derived from averages gath-ered from across the entire range of the species. Tables 1 & 2 listaverage temperature and relative humidity levels from across thespecies’ natural range for periods ranging from 4–23 years. I have derived the following environmental maintenanceschedule from these data. Averaging the recorded temperaturedata and buffering them by 4 °F toward the median, provides atemperature range within which any individual, regardless ofgeographic origin, can thrive. Recommended daytime high andnighttime low temperatures for captive C. caninus should be 84 °F (DTHT) and 74 °F (NTLT), respectively.Although some keepers use the same data to regulate rela-tive humidity (RH) levels, years of experimentation have led meto depart from levels found in the wild. Table 2 reflects daytimerelative humidity highs (DTRH) and nighttime relative humid-ity lows (NTRH) averaged from eleven locations across thespecies’ range. The data from which these averages were derivedwere collected over periods from 2–21 years. The reason Ichoose to deviate from these natural averages is the negativeeffect of sustaining such high RH levels within enclosures.Without the natural cleansing processes found in nature, blackmolds tend to grow in very high concentrations. These moldsproduce spores that become air-born and eventually settle onand adhere to every porous surface in an enclosed habitat. Evenover relatively short periods, such concentrations present anunnaturally high risk of infection or allergic reactions for bothsnakes and human handlers.Therefore, over the years, I have adopted modified RH lev-els that have proven completely adequate, enabling me to main-The “Northern” variety of Corallus caninus (left; this animal is fromSuriname) is more commonly available, although the Amazon Basinvariety (right) appears to be hardier and more resilient.Table 1. Temperature (°F) and precipitation (inches) averages across the range of Corallus caninus. Portions of the species’ range areindicated by N (= north), S (= south), E (= east), and W (= west). RF = rainfall.Area JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DECN-Hi 86 86 87 88 87 88 89 90 92 92 90 87N-Lo 72 72 72 73 74 73 73 74 74 74 74 73RF 8.2 5.6 6.1 8.4 11.7 11.7 9.1 7.0 3.6 3.6 4.8 7.4S-Hi 91 91 90 90 88 88 90 92 93 93 91 90S-Lo 72 73 72 70 66 63 61 64 69 72 72 73RF 10.0 8.6 8.1 4.0 2.2 0.5 0.3 1.1 1.8 5.2 6.0 8.1E-Hi 87 86 86 87 88 89 88 89 90 90 90 90E-Lo 76 76 75 75 75 75 75 75 76 76 77 77RF 10.5 10.0 11.8 12.0 10.5 8.2 6.4 6.5 7.5 9.1 9.8 10.2W-Hi 88 87 87 87 86 85 85 87 88 88 88 88W-Lo 73 73 73 73 73 72 71 72 72 72 73 73RF 10.5 10.0 11.8 11.9 10.5 8.2 6.4 6.5 7.5 9.1 9.8 10.2Iguana 13.2 b&w text.QX6  6/26/06  1:20 PM  Page 135tain a healthy population of tropical species while minimizing theexcessive formation of fungal pathogens. While actual RH num-bers for each individual facility will vary according to the funda-mental variables of area versus air circulation, DTRH levels from65–75% and NTRH levels from 45–55% have proven ideal.DietLike that of most opportunistic ambush predators, the naturalprey of C. caninus in the wild is known to vary widely. For thepurposes of captive maintenance, we deal with three majorsources of nutrition, all rodents. Rats, mice, and Siberian DwarfHamsters are most commonly used. Each species may be fed atvarious stages of a snake’s development. I use the followingguidelines in my facility (species may vary, but approximate sizesshould be watched closely):• Siberian Dwarf Hamsters (live crawlers, ± 8 g): Initiatingthe natural feeding response in neonate snakes.• Pink rats (live or frozen/thawed, ± 8 g): Neonatemaintenance once a solid feeding response has beenestablished.• Fuzzy rats (frozen/thawed, ± 16 g): Neonates > 60 g.• Rat pups (frozen/thawed, ± 25 g): Yearling snakes > 200 g.• Weanling rats (frozen/thawed, ± 35 g): Two-year oldsnakes > 350g.• Small rats (frozen/thawed, ± 75 g): Sub-adults > 500 g.• Medium rats (frozen/thawed, ± 150 g): Adult animals > 900 g.• Large rats (frozen/thawed, ± 250 g): Adult females > 1500 g.In an effort to promote optimum fitness while avoiding obesity,which may shorten lifespan and reduce reproductive productivity,feeding schedules and maintenance records on every individualshould be meticulously maintained. Such records are a crucial toolin managing these snakes, given their naturally low activity levels,which, exacerbated by captivity, are susceptible to a number of GI-related maladies. Avoiding these illnesses is relatively easy, giventhe proper tools and understanding their use.Feeding frequency at my facility varies according to age andsex. Younger specimens are fed most frequently, on a 10–14-dayschedule from 30 days until approximately eight months of age.The latter frequently coincides with ontogenesis, which is signi-fied in C. caninus by a change in ground color from neonatalred, green, or yellow to the familiar adult shade of green.However, this change, which is itself an energy-related process,is not inherently tied to age.Neonates whose GI tracts are fully engaged at an early age,process meals and eliminate wastes on a fairly regular, predictableschedule. Such individuals will benefit from being kept on a 10-day feeding interval. Animals with tendencies to process mealsless quickly should be held to a longer 14-day period. Under no136 IGUANA  •  VOLUME 13, NUMBER 2  •  JUNE 2006 POLANCOFrozen food size references.Live Siberian Dwarf Hamster (crawler) with dime for size reference.Table 2. Relative humidity table (%) averaged from across the entire range of Corallus caninus. DTRH = daytime relative humid-ity highs; NTRH = nighttime relative humidity lows.JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DECDTRH 94 94 94 95 95 93 92 91 91 91 91 93NTRH 76 78 77 78 77 72 68 66 66 67 70 76An 18-month-old Corallus caninus on a scale for size reference.Iguana 13.2 b&w text.QX6  6/26/06  1:20 PM  Page 136circumstances should a neonate be fed more than two mealswithout a bowel movement. A majority of neonates will elimi-nate the waste products from its previous meal within a fewdays. This waste is literally being moved out in order to makeroom for the wastes generated by the digestion of newly ingestedprey. Should an animal take two meals and fail to produce abowel movement, one should induce elimination. This can bemost easily accomplished by encouraging simple exercise onapproximately day eight following the second meal. Allowingthe animal to crawl freely over one’s open fingers from hand tohand for a period of ten minutes is usually enough to producethe desired result within hours of the session.For animals from 8 months to three years of age, a 14-dayinterval between meals is appropriate. From this stage forward,no individual should be given more than three meals betweenbowel movements. Once an animal has begun eating small ratsweighing > 75 g, feeding frequency can be reduced from 14 to18 or even 21 days. Females can remain on this schedule, butmales, having reached sexual maturity (at approximately fouryears of age) should be shifted to a monthly feeding routine. Theone exception to these adult feeding schedules is made in prepa-ration for breeding. Because cessation of feeding is common forboth males and females during different stages of the breedingprocess, “padding” the energy reserves of both during the weeksprior to the onset of the breeding season is prudent. For animalsslated for breeding in a given calendar year, I reduce the num-ber of days between feedings to the shortest periods mentionedpreviously for their respective sexes. Males will be fed (offeredfood) every 21 days and females every 18 days beginning 60days prior to introductions and lasting throughout the entirebreeding season. Many males will lose interest in feeding shortlyafter an initial introduction and may not feed again for the restof the season. By contrast, females will usually feed ravenouslythroughout the season and stop only after ovulation.Occasionally, males that are not actively breeding will alsostop feeding during this period. For this reason, sexually mature,non-actively breeding males should be removed from the imme-diate area in which breeding pairs are being housed.AcknowledgmentsFor general help and sharing of information over the years, andfor this particular project as well, I thank John Benz, RolandoBurgos, Stan Chiras, Craig and Karen Clark, Frank Fusaro,Robert Henderson, John Martin, Al Montejo, Tony Nicoli, andthe entire online Corallus community of readers and participantsat http://www.thetreeboaforum.com. Your passion inspires andpushes the work forward.ReferencesHenderson, R.W. 1993. Corallus caninus. Catalogue of American Amphibiansand Reptiles (574): 1–4.Stafford, P.J. and R.W. Henderson. 1996. Kaleidoscopic Tree Boas: The GenusCorallus of Tropical America. Krieger Publishing Co., Malabar, Florida.Adult animals should receive food commensurate with their size; inthis instance, an adult female boa consumes a large rat.IGUANA  •  VOLUME 13, NUMBER 2  •  JUNE 2006 137CORALLUS CANINUSHighly arboreal treeboas rarely descend from elevated perches, even toconsume large prey.Iguana 13.2 b&w text.QX6  6/26/06  1:20 PM  Page 137

Emerald Gems (Corallus caninus): Captive Husbandry and Propagation: Part II: Acquisition, Maintenance, and Diet

The University of Kansas: Journals@KU

https://journals.ku.edu/iguana/article/download/17605/15864

Emerald Gems (Corallus caninus): Captive Husbandry and Propagation: Part II: Acquisition, Maintenance, and Diet

Abstract

Similar works

Full text

Available Versions

Biodiversity Informatics

The University of Kansas: Journals@KU