Webmaster's note:   This paper, presented by Trooper Walsh in 1977, describes the first U.S. breeding of the Green Tree Python by a private breeder, and is the first of several papers authored by Mr. Walsh documenting his early work with this species.  Fine GTPs extends thanks to the author for his permission to reprint the papers and accompanying photographs here, so that current and future chondro lovers may have access to them at any time.  The 1977 paper is a fascinating look into the early attempts to breed this species in captivity, and also illustrates how far we have come with our knowlwedge of this species, thanks in large part to the continuing work of Mr. Walsh for over 25 years.

The author and the webmaster wish to emphasize that this paper presents techniques and information that was new or current at the time the paper was written.  However, there has been a great deal of knowledge gained since then, resulting in many changes to captive husbandry and breeding techniques for chondros.  This reprint is intended to provide insight into the techniques that became the foundation for further work, and to help preserve the wonderful heritage of this species in captivity.  However, much of the information is now considered outdated, and should not be used as a strict model for captive breeding.   The Genus Chondropython has also since been changed to Morelia.   The original nomenclature has been used to help preserve the feel of the original document.

Husbandry and Breeding of Chondropython Viridis

Trooper Walsh

Private Breeder, Washington, D.C.

 INTRODUCTION

Chondropython viridis is a beautiful, nocturnal, arboreal biod which is the only known species within its genus. It is native to the mountain-valley rain forests of New Guinea, some of the smaller Indonesian Islands, and has recently been discovered on the Cape York Peninsula of Northern Australia. Although not rare over most of its range, Chondropython has never been very common in private collections or zoos.

The purpose of this paper is to describe and discuss the husbandry and breeding of Chondropython in the author's private colony, and to compare these results with those of other individuals who have worked with this species.

Between February and August 1976, the author acquired 2.6 Chondropython. Of these specimens, 2.5 had been in captivity for at least one year prior to purchase. Two of this group had been captive raised, one from a wild caught juvenile, the other from a captive hatching (1973) at the Steinhart Aquarium. One of the eight specimens was a recent wild caught import. Sizes ranged from approximately 120-180 cm. with color and pattern varying from solid, light lime green to dark emerald green with blue dorsal markings and scattered white speckling.

HOUSING AND HUSBANDRY

Author's 1976 facility, click to see the full size image

Specimens were maintained individually in terrariums measuring 16 cm. x 31.5 cm. x 47 cm. Horizontal bamboo perches 5 cm. in diameter were sealed with aquarium cement to the glass tank walls at a height between 28 and 38 cm. above the floor. One perch was attached lengthwise and two were set up widthwise, one at each end of the terrarium. Plastic ferns were hung from the tank rims abd fanned out over certain areas of the perches, offering suitable cover for the Chondropython. Newspaper substrate was used in all the terraria. Water was available from bowls at one end of the cages at all times. Specimens have been observed drinking from bowls, as well as from moisture collected from daily mistings, which beaded up on their backs and in small pockets between coils. It is the opinion of the author that Chondropython in their native habitat may obtain much of their drinking water in the latter fashion.

Heat was supplied to the enclosures by four lengths of 125 watt heat cables, placed widthwise under one half of the slate bottomed terrariums. Shields made of wood frames covered with polyethylene were placed over the conventional screen tops to retain heat and humidity while allowing light to pass through. These shields were movable in order to produce changes in temperature and humidity within a 24 hour cycle. The average daily environmental cycle consisted of a cool, dry period in the late night-early morning hours (23.89C (75F) 55% humidity), a gradual climb in temperature througout the day, and a peak temperature and humidity in the late afternoon-early evening (30C (86F) 100% humidity). The warm humid atmosphere would slowly taper off late at night until the begimming of the cycle the following day.

Light was supplied by a combination of florescent vita-lite and white lights, suspended 20 cm. above cage tops. The lights were set on timers, allowing a year-round 12 hour light, 12 hour dark cycle. The daylight cycle began at 5:00 a.m., and ended at 5:00 p.m. With the onset of the nocturnal period, low watt red lights went on, enabling the author to see and wrok with the specimens without their being disturbed. The snakes were fed and manipulated during their noctunal activity period while under red light. Cages were generally cleaned in the early mornings when the specimens were at rest and under the daylight cycle.

FOOD

All specimens were maintained on a diet of small rodents. Occasionally, chicks were fed for variety. Adult Chondropython appear to have a slower metabolism than most small boids, resulting in a relatively infrequent need for food. Several large and old specimens in the author's breeding project were fed the equivelent of one 15 gm. rat every three weeks. Young adults were fed approximately 40 gm. of rats or mice every two weeks. Generally, the frequency of feeding can be determined by the rate of defecation. Specimens prowl for food usually within 24 hours of defecation. Sub-adult and juvenile Chondropython appear to have a faster metabolism than adults, and feed and defecate more frequently.

RECORDS

Individual data cards are kept on all specimens, and these accompany the animals as they are manipulated from one cage to another. Information recorded on these cards include feed charts, shed cycles, medications, cage manipulations, pairing of specimens, courtships, unusual behavior, and quarterly weights. In addition to the individual data cards, a daily log is kept to keep track of major events, such as breeding cycles, changes of environment and housing, egg laying, hatchings, and husbandry techniques. This information has been extremely helpful to the author in all aspects of the project.

HEALTH CARE

Fecal checks have been run on a number of the Chondropython in this project as well as with specimens at the Sedgwick County Zoo (SCZ). Results suggest that this species is a host for a wide variety of internal parasites. Strongyle and Hookworm were found in most of the specimens tested. Tapeworm, oxyurids, and roundworms were also noted.

Because of the high concentrations of parasites, it was decided to worm all the specimens in the author's colony. Thiabendazole (T.B.Z.) and Telmin were used for all parasites except tapeworm. Yomecan was used for tapeworm. The first worming was tubed into the Chondropython on an empty stomach. After two weeks, a second dose of the appropriate wormer was injected into a small feed item and fed to the specimens. Every few months additional fecal checks and wormings were done to keep the parasite levels down. No major problems have resulted from worming with Telmin, T.B.Z. or Yomecan, other than a brief loss of appetite with two of the specimens treated. Another wormer, Vermiplex, was tried, but the snakes rejected feed items injected with this odorous substance.

During the breeding season, males may rub their nostrils raw while prowling in search of females. This may be avoided by offering the active animals a female or by simply placing them in a larger cage.

COURTSHIP, COPULATION AND RELATED BEHAVIOR

In early August 1976, one male and two females housed nearby became increasingly restless during the evening hours. This activity was not associated with the feed drive, since all specimens had recently devoured large meals. Nevertheless, food was offered to the wandering specimens, but was rejected. Shortly before midnight on August 8th, it was decided to pair up the restless females with males. The first pair, which included the previously restless male, showed immediate interest in one another. The male began to follow the female over the branches and around the perimeter of the cage. The female twice excreted a small amount of uric acid on the branches and subsquently rubbed her vent along the surface. The male trailed the female until he had overtaken her where they came to rest in the highest branch at one end of the cage. Both specimens then coiled loosely over the perch in an interwoven fashion with the rear portion of the male's body on top of the female's. The male began to slide the rear of his body down the lower doral area of the female as his body convulsed and his spurs titillated the surface of the female's back. Eventually, the male positioned himself vent to vent with the female as the last 25 cm. of their bodies hung down in an intertwined manner. The male titillated the female's vent with his spurs, and she opened her cloaca so the male could invert and insert his hemipene. The entire courtship took approximately one hour, and copulation continued for 5 hours. Throughout the copulation process, both specimens hung their heads in seperate downward directions with apparent indifference. The muscles on the side of the male's body near the hemipenis were visibly pumping during initial stages of copulation. Both specimens remained together on the same branch throughout the day and copulation occurred again that night. The pair finally seperated to different branches on the morning of August 10th and did not show any signs of breeding activity that night.

On the evening of August 11th, the inactive male of the second pair was pulled and the breeding male substituted. Later that same night courtship-copulation occurred with this new pairing.

For the next two months, the breeding male was manipulated to and from the cages of the two females. At times, when the courtship subsided, the male was returned to his own cage for a period of days until either he or a female became unusually active. Throughout the period from August until early October, the breeding male and the other male were introduced to the other four females and no other sexual activity was observed. In total, both females were bred nine times. The first female was bred on 8/8/76, 8/9/76, 8/16/76, 8/19/76, and 10/1/76. The second female was bred on 8/11/76, 9/14/76, and 9/27/76. Physical contact lasted from 3 to 14 hours, although actual insemination was brief and intermittent. Most copulations took place on the perches, beginning in the warm, humid, evening hours. But, copulation was observed while both specimens were on the cage floor. At dawn, breeding activity subsided, although the specimens would sometimes remain intercoiled throughout the day. No breeding activity occurred while either sex was in shed. The most aggressive sexual pursuits by the male accurred after a fresh shed by females. The sexually active male went off feed soon after the first breeding. The two females continued to feed intermittently for some time.

PRE-LAYING ACTIVITY

Between September and December of 1976, both bred females gained almost 400 gms. in body weight. From mid-November neither specimen accepted food. After December 19th the first female to breed became very secretive, staying in one spot under a fern. This normally aggressive specimen also turned timid, preferring to bury her head in her coils rather than come to alert when disturbed.

On December 17th, the first female to breed was set up in a new and larger cage, offering more seclusion than her small terrarium. This cage contained three other females which had recently been placed together. The cage measured 120 cm. long x 76 cm. wide x 92 cm. high. The back, the two ends, and the floor were solid plywood while one half of the frontal viewing area was glass and the other half wire mesh covered with polyethylene. The half made of wire and polyethylene had a canvas drop sheet, and the lower one-third of the glass portion was painted to offer extra seclusion to the specimens. There were doors at either end of the cage which allowed limited access. The hinged top was wood framed and covered with polyethylene and styrofoam. A hinged section of the top opened for ventilation.

Heat was provided by heat cables under the floor of the cage and a 75 watt incandescent Vita-lite was constructed onto the hinged top. In addition to the Vita-lite, a 25 watt red light was installed so nocturnal observations could be made. Temperature, humidity, and light cycles were the same as the smaller terraria. The cage floor was covered with 8 cm. of ground tree mulch. Horizontal bamboo perches and hanging plastic ferns were set up in much the same way as in the smaller habitats.

On December 27, the gravid female started to become restless in the evening hours. During the day, she would stay perched in seclusion on the highest limb, but just after sunset she would prowl the floor and perimeter of the cage. This activity looked calm: she simply investigated every part of the enclosure. The evening prowls occurred regularly from December 27 on, but she usually settled back on her favorite perch by early a.m. On December 27 it was noticed that her near solid lime green color had become unusually light.

At 8:00 p.m. on December 31, she was found tightly coiled on the ground in a secluded corner. She remained there for several hours and then returned to her perch. At this time a selection of possible laying sites were set up as follows: An upright hollow log in the corner of the cage where she was first seen coiled on the ground; a horizontal hollow log secured 61 cm. above the substrate along the back wall; a large plastic bush set in another corner on the substrate; and a flat, rectangular hide box with a small hole at one end and a slide top. The box (38 cm. x 25 cm. x 10 cm.) was placed on the substrate in a third corner.

The gravid female investigated all possible laying sites in the next few evenings, only coming to rest in the bush and in the box, but always returning to her perch before daylight. None of the other females in the cage showed any interest in the newly added cage material or exhibited any of the behaviors of the gravid individual. No interactions were observed among the females.

At 10:30 p.m. on the night of January 2 the gravid specimen was seen stretched out on the substrate and moving an abdominal mass with rippling motions toward the vent. Simultaniously she poked the mass gently with her snout. At this time she raised her tail and expelled a small amount of uric acid. Within 20 minutes she returned to her perch.

On the night of January 11, she entered the hide box and remained there, not returning to her branch in the morning as before.

EGGS, INCUBATION, AND POST LAYING ACTIVITY

Author's 1977 first-ever private CB clutch, click to see the full size image

On the night of January 12, between 9:00 p.m. and 11:00 p.m., she laid a clutch of 25 eggs in the hide box. The eggs were laid in a pile clutch and most were adhered together, with the female coiled tightly around the mass. The female exhibited no signs of thermoregulatory body twitching as described for brooding Python molurus (Vinegar, 1970) and for Chondropython (Kratzer, 1962).

The eggs were removed from the female, separated, and set up for artificial incubation. The female remained coiled tightly on the ground for two days after laying. Her green body color had become darker than usual after laying, which was in contrast to her abnormally light green appearance during the last weeks of pregnancy. Conception is thought to have occurred October 1. The pre-laying shed was recorded December 23, 1976 and a post laying shed March 15, 1976, eleven days after the eggs began to hatch. Her first meal was accepted 10 days after the clutch was laid and removed. By mid-January of 1977, the second female to breed went down to her normal body weight and resumed feed.

Of the 25 eggs, 22 were determined to be fertile using a bird egg candler. One of the fertile eggs exhibited a blood ring on the inside top of the egg and was found to be dead. The eggs were individually marked, weighed, and measured. The eggs averaged 13.90 gms. in weight and 37.85 mm. x 27.53 mm. in length and width. The total clutch weight was 347.60 gms.

To help retard mold, the eggs were dipped in a 10% Clorox solution, rinsed, and toweled dry. Two metal framed glass terrariums measuring 51 cm. x 27 cm. x 31.5 cm. were set up as incubators. The screen tops were covered with polyethylene shields and each had eight small holes in two rows down the center for ventilation. Seven centimeters of sterilized pea gravel was used to cover the tank floors. This was done to elevate egg containers from subterranean heat and to aid in retaining heat when tanks were opened and checked. The eggs were placed on top of Baccto potting soil in individual plastic cups which measured 11 cm. x 11 cm. x 8 cm. Two rows of egg cups were placed in each tank on the pea gravel. The tanks were placed over two lengths of heat cable. Newspaper covered the outside glass of the tanks for further insulation. Humidity was supplied by adding water to the pea gravel substrate to a height of 3 cm. from the tank floors. The heat cables under the tanks raised the humidity until condensation appeared on the inner glass walls. No moisture was added directly to the soil medium under the eggs.

The two tanks were maintained at two different temperatures. Tank one was set at 28.33C (83F) and tank two was set at 30.56C (87F). The lower temperature in tank one was accomplished by elevating the tank 3-5 cm. off the heat cables with two pieces of wood placed lengthwise under the edges of the bottom. The employment of two different temperatures in the individual tanks was done because of the lack of information on incubation temperature for eggs of this species at that time.

During the first few weeks, three eggs molded and spoiled in tank two. Two of these were previously determined infertile and the third was suspected dead when candled. Towards the end of incubation, eggs in this tank developed transparent areas. The warmer tank was allowed to air out-cool off, and the transparent areas returned to their normal creamy color, but the eggs eventually spoiled. Of the six viable eggs in this tank, four embryos developed to approximately 3/4 of the hatchlings size before dying. It appeared that excess heat and moisture caused the total loss of the eggs in tank two. All but two of the eggs that died in tank one developed nearly completely before succumbing.

HATCHING AND HATCHLINGS

The eggs in the cooler tank began to hatch on March 4th, 51 days after laying. In total, ten young pipped. One hatchling was unable to leave the egg due to an excessively long umbilical cord which wrapped around the midsection of it's body and strangled it. Two other embryos went full term, but did not pip, and two embryos reached 3/4 development and died. All hatchlings and full term embryos were the same color phase of bright lemon yellow with red dorsal lines, diamonds, head markings, and side speckling. All juveniles also possessed whites tails ringed with black bands.

In total, nine healthy young hatched. The hatchlings were easily identified by individually different head markings. All hatchlings were probed and a 4.5 sex ratio obtained.

HATCHLING HUSBANDRY

The nine juveniles were set up in three cages, three specimens per cage. Terrariums measuring 52 cm. x 27 cm. x 31 cm. were used and set up much the same as the adults but on a smaller scale. Pea gravel was used as substrate instead of newspaper. The juveniles immediately took to the provided branches and perched in an inner-looped coil similar to the adults. First sheds occurred 10-15 days after hatching. Caudal luring was first noticed at this time. The night of the first sheds the young began to prowl during the evening period of high temperature and humidity. Four specimens were then coaxed into accepting pink mice, after biting, constricting, and dropping food many times. Prior to the first shed, pink mice, small frogs, and anoles had been refused. The remaining five young were assist-fed pinkies for their first meals. The author later learned a method of feeding the juveniles, which saved time and exercised less stress to the specimens. Previously they had been coaxed into first biting and then constricting food. It was discovered later that when they were hungry, they would come to attention and stretch out a forward coil when disturbed. A pink on forceps touched to the anterior part of the body was constricted and killed without biting. The pink was then passed from coil to mouth and swallowed. This method resulted in fewer prey items being dropped, and more successful, quicker feedings.

At three weeks of age, 8 of 9 baby Chondropython had fed on pinks of their own initiative. Throughout the feeding trials, an evening temperature of 30C (86F) and high humidity was maintained. All successful feeding attempts were executed under dim red lighting.

The baby snakes that were kept by the author continued to feed well, and were aggressively feeding on half grown mice by their fourth month.

DISCUSSION

Very little data is available on breeding Chondropython in captivity. The following discussion is based on the present paper, further work done by the author since the 1976 breeding season, the literature and personal communications with field collectors and other breeders.

Breeding Chondropython in captivity appears to be relatively easy once basic environmental needs are provided for and compatible opposite sexes are present. It appears that temperature and humidity cycles, both seasonally and daily, play an important role in inducing successful breeding of this species. It is the opinion of the author that photoperiod does not greatly affect Chondropython breeding cycles. The cage facilities and environmental cycles employed by the author and described in this paper, were developed to simulate breeding conditions within this species natural habitat.

Work done in three controlled captive situations besides that of the author, show successful copulations recorded May through July, with eggs laid from late July through September (Kratzer, 1962; S.C.Z., 1997; R. Murphy, personal communications). In these instances of captive breeding, the time between last matings and egg laying ranged from 70 to 79 days. Incubation periods ranged from 47 to 51 days, with eggs hatching from September to November. Clutch sizes ranged from 12 to 26 eggs.

Data from wild caught gravid females, and captive bred specimens has been analyzed by the author to determine possible breeding cycles of Chondropython within their natural range. From known gestation periods, it is theorized that mating occurs from May through July during the wet season. Switak (1975) and Schrock (personal communications) report eggs laid in late August from wild caught gravid females. Hatching was observed by Switak (1974) in October. This corresponds to a second wet season in the natural range of this species. The wet seasons probably offer juveniles prime chance for finding food and surviving.

The author and the S.C.Z. feel that Chondropython may breed twice annually in some parts of its range. This is evidenced by copulations observed by the author, S.C.Z., Wright and Lincoln (personal communications) in October through December of 1976. The author's subsequent clutch described in this paper gives support to this theory. It is known that many animals in the tropics do breed twice annually, but more field data must be collected to determine if this is true for Chondropython. It is also possible that Chondropython may breed throughout the year in some parts of their range, in accordance to varying climate peaks.

The author, Kratzer, the S.C.Z. and Murphy employed similar methods of inducing copulation by introducing sexes after periods of separation and during simulated rainy seasons with daily temperature fluctuations. It was observed that vigorous courtships often followed a female sloughing.

When a male was initially introduced to an active female during a breeding cycle, the females would deposit small amounts of uric acid on the cage branches which appeared to incite activity in the male, copulation often resulting.

It appears that periods of restlessness and subsequent breeding activity in the author's breeding colony (1976-1977) may also have been influenced by afternoon low pressure systems and thundershowers. The room where the author's colony is housed is partially exposed to outside weather conditions in warmer months. When a low pressure system does occur in the area, and restlessness is observed with individual Chondropython, an extra cage misting is performed, pairing of sexes done, and copulations usually result. It is necessary to provide a drying, cooling period during a 24 hour cycle in a captive situation. If specimens stay constantly hot and humid, bacteria and fungal problems may result. Switak (1975) mentions the possible importance of day-night temperature fluctuations in reference to stimulating Chondropython breeding cycles for females to produce fertile eggs.

It is the opinion of the author that female Chondropython Come down to the ground to lay eggs and may coil around the clutch to protect them. This is demonstrated by the observations of the author involving the four possible laying sites, and the activities of the gravid female discussed earlier in this paper. The S.C.Z., Kratzer, Murphy, and Schrock confirm this behavior by observations with their laying females. It is not known if a brooding female Chondropython actually raises her own body temperature as do brooding Python molurus. Kratzer (1972) reports body convulsions at two to three second intervals with his brooding female. He was unable to assess whether or not this activity generated heat. The female in the author's study was not observed twitching.

Very little is known about egg incubation temperatures for Chondropython in the wild or captivity. Being a boid, it is the opinion of the author that eggs from this species would require a fair amount of heat and humidity. But, the eggs of Chondropython are relatively small when compared with eggs of larger Python species. Thus it is felt that the smaller Chondropython eggs might be incubated at a lower temperature than the large eggs of other species.

The S.C.Z. (1976) hatched 6 of 26 captive conceived Chondropython eggs using a temperature of 30C (86F). Kratzer (1962) and Switak (1975) report a better hatching success at temperatures between 28-29C (82.4-84.2F). It appears that desired incubation temperature may be in the low 80's F with high humidity.

Since the 1976 breeding in the author's facilities, 6.4 additional adult specimens have been obtained. On February 1977, 4.1 newly acquired specimens were housed together, and that night one of the males began to court the female. Two other males soon became excited, and began to court each other. Within several minutes, one of the excited males struck out and grabbed the head of the other male, coiling around its body and falling to the cage floor. The bout was quickly broken up by the author, and all the males immediately separated into individual cages. Similar aggressive male interactions have been observed by the author in South American Garden Tree boa, Corallus enydris "hornulata".

Recently, large communal cages have been put to use for groups of female Chondropython. No aggressive interactions have resulted with the females. All male and some female specimens are still maintianed in individual terrariums.

The 1977 breeding season begain in the author's colony in early June. This summer both sexes have been introduced to one another with copulations resulting. Generally females have been introduced to males on a one to one basis. Individual males have been introduced into the females' communal cages, and successful breeding has occurred. In this situation, when a male and female are in copulation, the other females have shown no interest or excitement in the breeding pairs. This fact, and the aggressive male interactions observed earlier in the year, lead the author to believe that male Chondropython are more territorially aggressive than females.

Among the more recently acquired specimens to breed is a pair of rare blue phase Chondropython. The blue male has also bred a normal green phase female. The author hopes the possible offspring from these two females will help shed some light on the inheritance of color in Chondropython.

It has yet to be determined whether blue phase Chondropython are blue after hatching, or if they acquire this pigment after undergoing a color transformation upon maturity. Known offspring from the normal green phase Chondropython are variable in color and pattern, being red, brown and yellow at hatching. The juvenile coloration changes slowly to the adult green in approximately two years.

In this summer's breeding season, seven female specimens have bred with four males. A running total of 55 copulations have been recorded between June 12th and July 31st. It appears that some males have become more sexually active and others have slacked off during this period. Egg laying is expected to begin in late August.

The author plans to experiment with different incubation procedures using the optimal temperatures and conditions mentioned in this paper. Experimentation will include setting up females to brood their own eggs to determine whether or not thermoregulatory activity is involved with incubating females of this species.

Hopefully, from shared experience, more captive conceived Chondropython will be produced, both in the author's colony and those of other breeders. Continued captive breeding and future field studies should enhance our knowledge and assure this and other unique species survival in captivity.

ACKNOWLEDGEMENTS

I am extremely grateful to Dr. Dale Marcellini, Research Curator of Reptiles and Amphibians at the National Zoological Park (NZP), for his assistance in preparing this paper.

I would like to thank Sheffield Edwards for offering suggestions and support at all stages of this project, and for information he has shared through the years from his Herpetological field studies in the tropics.

Special thanks are in order to Mike Davenport, Curator of Reptiles at N.Z.P.; Brenda Hall, keeper at N.Z.P.; Tom Vines and Tracy Miller for reviewing the manuscript and secretarial services rendered.

I would also like to thank Janice E. Williams and Karen Poling for the english translations done on the German Chondropython publication.

REFERENCES

Kratzer, H. (1962): Surprise breeding of Chondropython viridis. Aquar. Terrar. Zeitschr. (4), 177-179

Sedgwick County Zoo (Gray, P., 1977): A captive breeding of the Green Tree Python, Chondropython viridis. Paper given at the second annual Reptile Breeding Symposium, Cleveland, OH.

Vinegar, A. (1973): The effect of temperature on the growth and development of embryos of the Indian Python, Python molurus. (Reptilia: Serpentes: Boidae) Copeia, 1973: 171-173

Switak, K. (1975): The Green Tree Python from the land of the cannibal. Aquar. Terrar. Zeitschr. (9): 366-372

PERSONAL COMMUNICATIONS:

Murphy, R. (1977)

Lincoln, M. (1977)

Wright, D. (1977)

Schrock, G. (1976)