Die asiatischen Sumpfschildkröten
der Gattung Cuora (GRAY, 1855)

Abstract

The male of the Asian snail-eating box turtle Cuora flavomarginata mated several times in February and March with the two females kept in the same Aqua-Terrarium. The females laid seven clutches of together eleven eggs into the soil (damp sand). Two eggs hatched after 95 and 101days of incubation in vermiculite, the temperature was at 28 ± 0,5°C, humidity about 95%. Two eggs hatched after 74 days of incubation in vermiculite, the temperature was at 29 ± 0,5°C, humidity about 95%. Some hatching data are given.
Key words:Testudines: Emydidae: Cuora flavomarginata; breeding; hatching data.

The Cuora-group with formerly 5 species, whereby yuanensis has not discovered again for the science since 1906 as a living animal, was expanded in the last 13 years with 4 new species: C. pani (SONG 1984), C. autocapitata (LUO & ZONG 1988), C. mccordi (ERNST 1988), and C. zhoui (ZHAO et al. 1990).
The stronger scientific interest to this group split some species into subspecies, so at C. amboinensis (RUMMLER & FRITZ 1991), C. galbinifrons (IVERSON & MCCORD 1992, OBST & REIMANN 1994), and C. flavomarginata (IVERSON, 1992).
The description of Cuora evelynae by ERNST & LOVICH (1990) as species from the Ryukyu - Islands caused MCCORD&IVERSON (1991) to the revision, resulting in Cuora flavomarginata formes three geographic subspecies (flavomarginata, evelynae, and sinensis).
Reports on keeping of Cuora refer almost exclusively to C. amboinesis (Fig.: 1), C. galbinifrons (Fig.: 2 u. 3), C. aurocapitata and C. trifasciata (NIETZKE 1969, 1973, PETZOLD 1963, 1965, PRAEDICOW 1985, NÖLLERT 1987, MÜLLER 1987, ALDERTON 1988, BASILE 1989, DEBRUIN et al. 1994, BECKER 1996). LORENZ (1985) mentiones in his publication "Die Schildkröten Südost Asiens" a breeding of C. flavomarginata without giving more details on the keeping and the incubating. ZWARTEPORT (1986, 1991) reports the keeping and breeding of C. flavomarginata.
BASILE (1989) and LORENZ (1985) classified C. flavomarginata because of the small distributionas endangered, in contrast to the WA - status, which declares this species not as endangered. Up to now their habitat has remained quite unexplored (PRITCHARD 1979, BASILE 1989, ROGNER 1995). Generally the prefered habitats are rice fields and monsun forests in medium altitude, that means swamps and wetlands with shallow water patches (PRITCHARD 1979, OBST 1985, MÜLLER 1987, BASILE 1989).
BASILE (1989) mentiones the feeding problems, which I could not report, because of my animals are always very greedy for food. A mixture of vegetables and assorted meat items, including earthworms, snails, cockroaches, giant mealworms, and pinky mice, is necessary for the well-being of the animals (MÜLLER 1987, BASILE 1989). Extensive investigations on the feeding behavior of C. flavomarginata were published by KORNMANN (1991).

In August 1989 I had the chance to obtain a semiadult pair of the species Cuora flavomarginata (Fig.: 4). These animals had spent already some time in the terrarium and had been fed exclusively with canned cat food, and they weighted 293 g (female) and 274 g (male). In the beginning the shift to different food items was not so easy. After offering them earthworms, which were always powdered with vitamin suplement, larvae of Zophobas, pieces of beef heart, and snails, the animals feeding behavior changed.
In January 1990 I purchased another female nearly fitting in size (161 g). The initial shyness of all animals got lost completely after about three quarters of a year. Now they also feed, beside the animal food, the permanently offered fruit items. The menu was expanded now with bananas, kiwis, overripe pears, strawberries, raspberries, blackberries, tomatoes as well as turtle pellets (PENK, Rüsselsheim), and turtle pudding (BECKER 1992). Apples, salad and dandelion are never fed till now.
The animals are housed in an aquaterrarium meassuring 100 x 40 x 40 cm LHB. The enclosure is subdivided by a glass-plate, which is glued at an angle of 40° into the enclosure, into two partitions. The smaller part is filled with water and the other part is filled with damp sand up to 10 cm. A flat stony plate in the water and a cork plate glued on the glass plate (Fig.: 5) allowed the animals the entrance and exit to the water partition (BECKER 1994a, b). The water partition is filtered by an Eheim filter 2011. The animals avoid deep water, so you have to pay attention, that the turtles are able to raise their heads easily over the water surface. The land part is heated with a heating pad (25 x 35 cm / 15W). Lighting is provided by one luminescence tube (Osram 18 W). Above the heating pad plates of sandstone were placed, so that in the middle of the terrarium an egg-laying place is accessibel. The terrarium is heated during the day up to 28 - 30°C, at night the temperature drops to 24 - 26°C.
The animals are always sleeping on the land partition under the slanting glass plate, where they have dug themselves a hiding-place.
I also tried wood-chips, soil, and turf as substrate, but the only practical material was sand. The animals pollute extremely the water, because of their intense digging activity and the constant walking between land and water.
Cuora flavomarginata are known as very quarrelsome. MEIER (pers. comm.) therefore recommended a single keeping during most of the year. Only during the mating season a socialization could be made. ZWARTEPORT (1986, 1991) reports, that he put together three males and one female in an enclosure meassuring 170 x 100 x 100 cm. The above mentioned keeping had worked, whereby biting and fighting starts immediately, if two males stay in the same terrarium.

Between December 1990 and the beginning of February 1991, I hibernated my animals for the first time. At first the heating mat was switched off, so the temperature would drop slightly in the enclosure. After the turtles dug into the ground, the luminescence lamp was also turned off and the whole enclosure was wrapped in paper to exclude light. The temperature during this period was between 10 - 15°C.
After the hibernation, the paper was firs removed, then the light was turned on. Two weeks later, the heating mat was also turned on again.

Four weeks later the male started mating with the first female both in and out of the water. Thereby the male approached the female with head bobbing, pushed his head and subsequently the whole body under the female, which behaved passively (LORENZ, 1985a). Copulations were only observed in the water. Sometimes the male starts biting into the edge of the carapax over the head of the female and starts to shake her. Thereby the animals faced eached other( HACKETHAL and PAULER pers. comm.). Thereby no injuries happened to the females. These mating seems to belong to the behavior of the animals. Unfortunately no egg-laying could be observed this year. Presumably the females of C. flavomarginata are first sexually mature after reaching a total weight of about 550g weight (HACKETHAL, pers. comm.).

Again after hibernation 91/92 I noticed mating behaviour in February and March at the same pair. The weight of the females increases, what means, that she is producing eggs. Therefore I decided to probe the female and could clearly touch two eggs in the space between plastron and rear leg. Thereupon I checked the animal daily. At March 28th 1992 realized during a control, that she must have laid the eggs. She deposited them into the sand between two sandstone plates, unfortunately one egg was crushed (clutch 1). The second egg, hard-shelled, oval and 46 mm long, was transferred into damp vermiculite and incubated at 28 ± 0,5°C in the self designed incubator. After 4 weeks, during an regularely illumination, I could see, that the egg yolk was placed at the bottom of the egg. There was no further development recognized and was the egg thrown away.
After the hibernation 92/93 I redesigned enclosure. I possitioned the sandstone plates as described above. One save egg depositing place was offered to the turtles, to prevent an unintentional destroying of the eggs. This time I could observe for the first time, that the male tried to copulate with the second female.
At April 26th 1993 I found two oval, hard-shell eggs, meassuring 43 mm and 45 mm in length, from the first female (clutch 2), which were transferred into a plastic container filled with damp vermiculite and incubated at 28° ± 0,5°C (BECKER 1995a).
At May 3rd 1993 I found at another two eggs at the same place in the enclosure. Both egg meassured 44 mm in length an must be from the second female (clutch 3).
On May 27th 1993 the first female laid again one egg (clutch 4), which was significant smaller than the other eggs. It meassures only 35 mm in length. This egg did not develop and was rejected after 4 weeks.

fertile C. flavomarginata egg, a banding is clearly visible

At a routinely control after about one week, I could ascertain at one egg of each clutch (2 and 3) a clear separation between a light coloration in the middle and two darker parts on each end of the eggs. The other eggs did not develop.
Again after the hibernation 93/94 I could observe mating behavior with both females. Durind a routinely control at the beginning of May I realized, that female no. 2 had increased in weight,and I made out at least an egg. After some 14 days I realized by checking, that the female must have laid their eggs. I first digged in the egg-laying place, but could find nothing. Then I looked through the rest of the land partition of the enclosure. Unfortunately I could not find any egg.
At June 30th 1994 I cleaned the water and sand of the aqua-terrarium. Thereby I found egg, which might be laid in the middle of May. The female had placed the egg below a sandstone plate, which was positioned on one side of the egg-laying place. That was the reason why I could not find the egg in May, because it was very difficulty to discovered this place (clutch 5). During the maintenance I broke the egg, and a embryo of about 10 mm could be seen, which just lived a short time after breaking the egg. The female had selected such an ideal place in this enclosure, that the embryo in the egg could develop in the terrarium, and could probably hatch, if the accident would not happen (BECKER 1995b).
At July 4th 1994 female no. 2 died. At the following postmortem I realized a round egg, with the size of a tabletennis-ball. The reason for the dead was egg-binding.
In November 1994 I had the chance, to purchase another semiadulte female, which was introduced to the enclosure of the breeding pair. She weighed about 300g and was considered little by the male. After the hibernation 1996/1997 this female weighs 521g and is included now in the mating behaviour.
In spring 1995 I have arranged a new terrarium, meassuring 100 x 60 x 50 cm, for the animals. Probably 1995 no egg-laying was seen. In the other terrarium another semiadulte pair was housed, which I could purchase in the spring 1995. These animals are different in coloration. They have more intense head pattern, where bright yellow stripes are surrounded by small dark stripes.
At May 9th 1996 female no. 1 deposited one egg (clutch 6). This egg meassured 59 mm in length, had a diameter of 23 mm, and weighted 19 g. It was much larger and heavier, than the other eggs (Fig.: 6). At June 27th the female layed again two eggs (clutch 7). These eggs were normal sized and weighted 10,3g, and 10,93g.
Each clutch was transferred in an extra container, which was filled with damp vermiculite, at ration of 65 g substrate and 150 g water. Incubation was at a temperature of 29 ± 0,5°C. At a routinely control after about one week I could see, that the large egg of clutch 6 and one of the eggs of clutch 7 showed developing. The other egg was infertile and did not develop.

At a control of clutch 2 in July 14th 1993, after 101 days of incubation, I saw that the first egg was opene at one side. A hatchling looked out. In the evening of this day the small turtle had left the egg. The yolk-sac was resorped completely. The hatchling weighed 10,4g, but no further data were taken. On July 30th 1993 (clutch 3) one hatchling emerged after 95 days. It weighed 8,7 g. Both animals looked healthy. They looked like a copy of their parents, only a clearly marked yellow dorsal keel points to a juvenile coloration (Fig.: 7).
The increased temperature, as well as a higher humidity of the vermiculite might have accelerate the incubation at clutches 6 and 7. At June 22nd 1996 a youngster from clutch 6 hatched after 74 days, weighing 12,71 g. At September 9th 1996 a young turtle from clutch 7 hatched also after 74 days, weighing 6,86 g.
Interesting with the last two hatchlings was, that the ratio between egg-mass and mass of hatchlings was always 1,5. This is very interesting, because the weights differed significantly. Some more studies should be made.

C. flavomarginata in an enclosure for young animals

The babies were housed in a terrarium measuring 50 x 30 x 30 cm (Fig.: 8). Wood-chips were used as substrate. Daily spraying of warm water kept the substrate always damp. A water dish with a diameter of 15 cm and a water level of 1,5cm was offered. Pieces of bark were introduced to the enclosure to prevent hiding places. Some plants (Scindapsus) completed the furnituring. A 40 W spot light provides a local heating place, which reaches about 28 - 32°C. The same food items as mentioned above were offered to the offspring.
The hatchlings dug themselves immediately after I introduced them into the terrarium. During the day they are hardly to be seen, they are only visible during twilight or early in the morning. They disappear immediately, if they feel observed. The animals increase well and rejoice best health. After about 20 months the weight of the halfgrown from clutches 2 and 3 are 191g and 143g (Fig.: 9). After about 43 months the weight of the animals from cluthes 2 and 3 is 340g and320g (HENKE, pers. comm.).

I would like to say thank you to BERND EIDENMÜLLER, for the help with the manuscript, for the translation and for the hints of the keeping of my animals. WOLFGANG LORENZ helped with some fruitful telephone conversations and for some papers to the theme. UWE HACKETHAL and FRITZ-JÜRGEN OBST made some helpful constructive suggestions to the manuscript. I would finely like to say thank you to ROLAND HENKE for giving me data on the first two hatchlings.