First captive breeding of Zhou's Box Turtle,
Cuora zhoui , in North America

David S. Lee and Leslie M. Levine
The Tortoise Reserve

All photos by Alex Siess

The Zhou's box turtle, Cuora zhoui , was not described until 1990. It is endemic to China but its exact distribution is unknown. All specimens to date have been recovered from live food markets in Guangxi and Yunnan Providences. The habitat of this turtle is also unknown, but the market animals are suspected to have been collected in remote hilly streams. While the population status is not known, based on the small numbers found in markets, the recent discovery of the species, and their absence from live food markets and the pet trade for a number of years, this Cuora was obviously a rare localized species and it is now believed to be extinct in the wild.

An adult pair of Cuora zhoui was donated to the Tortoise Reserve in early 2003.  After several months of quarantine and routine medical treatments, they were brought to our North Carolina captive breeding facility in March 2003 and introduced to an enclosure constructed specifically for this species. They measure 170 mm SCL by 117 mm (male) and 170 mm SCL by 126 mm in width (female). Weights varied from 686.5-788 grams (female) and 705-709 grams (male).

Though believed extinct in the wild, there are small numbers of Cuora zhoui in captivity. Inventories suggest that there are approximately 35 captive pairs in the United States and a similar number in Europe . Nearly all specimens are held by the private sector. The fate of this species appears to rest entirely on successful captive breeding, maintaining genetic diversity in subsequent generations, and commitment for long-term maintenance of captive populations.   All prior captive breeding of this species, to our knowledge, are the achievement of private turtle hobbyist and conservationist Elmar Meier of M ü enster, Germany, who is affiliated with the International Species Conservation Center at Zoo M ü enster and who generously shared with us  information about his successful husbandry practices with this species.  We report the first captive breeding of this species outside of Elmar Meier's German facility.   Of note is that the husbandry methods associated with this North American breeding are quite different from those used by our German colleague.

The adult enclosure in the greenhouse is in a back corner that remains cooler than the rest of the building, and it has less solar exposure at all seasons, The pen is 7 by 7 feet on the longest sides but because of an angled front side is only about 35 square feet in total area (for the most part, non-reptilian measurements are provided in English units to perplex scientists unable to cope with inconsonant descriptions and to confuse our European counterparts). Centered in this pen is a 50-gallon (100 liters) oval Rubbermaid ® tub buried to the level of the substrate. The tub measures 52" by 29" and is 11" deep. Because of a cooling fan, maximal summer daytime air temperatures in this section of the greenhouse are about 85 ° F. Minimal winter temperatures are 65 ° F. The water temperature is about 5 degrees cooler than the average air in the summer, and about the same as the minimal winter temperatures. The pen is landscaped with various plantings including a ground cover of sphagnum moss, black-stemmed elephant ear, prayer plant, an Asiatic terrestrial polpody, jewel orchids, and a small papaya tree. Several hides are available for the terrestrial turtles. The gravel-bottomed pond has an emerging cypress log (for both basking and maintaining water pH), and a few water hyacinths. It receives direct sun less than 2-3 hours a day.

Several additional temperate/sub-tropical turtles share the same pen (1.2 Geomyda spengleri , 0.1 Cuora pani , and 0. 1 C. galbinifrons ). Except for the Cuora pani the other turtles remain on the land portion of the enclosure. For the first several months, the male C. zhoui was housed in a 35-gallon aquarium inside the enclosure and was introduced to the female for only a few hours a week.  The male was allowed permanent access to the female once it became apparent that he was not overly aggressive and that the female took advantage of available retreats to escape his advances. These Cuora feed both day and night. Their main diet is floating fish pellets (36% protein) but they are also fed small live fish, earthworms, and small crayfish. Snails, dragonfly larvae, and aquatic plants that volunteered in the pool are probably also consumed. Once a week, sections of bananas are placed near the edges of the pool and within minutes the C. zhoui emerge from the pool and eat the bananas. If disturbed, they will often carry the banana wit h them when they crawl back into the pool. Late in the afternoon sun hits one side of the pool for about an hour and occasionally these turtles will bask if there is no activity in the greenhouse.

Zhou's box turtles are shy, and remain submerged in the water, typically hiding under a cypress log, throughout much of the day. When found undisturbed they are seen lying on the bottom with about 1/3 of their head extended above the water surface. Like other turtles in our collection, they are handled as little as possible and they have not become accustomed to people.

Mating was observed on a number of occasions starting as early as 22 March and continuing at least through early June. In late May 2004, the female was found on a number of occasions out of the water and was believed to be looking for a nesting site. On 5 June the pen, pool, and filter were given a complete cleaning. At this time the female was palpated and eggs could be felt. Two sand areas were added to the enclosure to serve both as nesting sites and as focal points for searching for the eggs. One was heated with a ceramic heater while the other was not heated. Four eggs were discovered about 4 inches below the surface of the sand in the shaded, and unheated nesting area on 19 June. The eggs were placed in an incubator on 22 June and they banded within a couple of days. They were very consistent in size and measured 48.9-49.1 x 23.9 mm. They were not weighed, but slightly exceeded 10 grams. Incubation temperatures were fluctuated between 78 ° F at night and 85 ° F during the day. After 90-91 days of incubation two eggs hatched between 16-17 September, the other two eggs spoiled early in the incubation process and when opened showed no indication of development. The first young turtle emerged with an extremely extended yolk sac, and soon died presumably because of infection resulting from the extended yolk. The second one hatched ca. 38 hours later. The absorption of yolk appeared normal on the second individual. Both young were kept in a non-abrasive, light-free container in the incubator for their first two days.

The failure of two eggs to hatch and the death of one young within 48 hours of hatching suggest that the eggs were not incubated properly. In the future we plan to incubate the eggs with ambient outdoor temperatures in the same way in which we incubate eggs of Cuora flavomarginata as well as Clemmys and other aquatic and semi-aquatic temperate turtles.

Description of young: The nose is extremely pointed, and the tail is proportionally long. Legs and tail black. The head is black dorsally. The carapace is also black, and the posterior marginals are slightly serrated. The bridge and adjacent ventral marginals have small yellow blotches, and the plastron is black with pale thin yellow-orange marking on the anterior and posterior edges and broken elongated yellow-orange marking on the mid seam. The net result is a yellow smiley face on a black plastron. No hinge is apparent. The weights ranged from 9.4-10.1 grams and shell measurements averaged 33mm SCL by 29.5 mm in width. By mid-October 2004 the single surviving hatchling appears healthy and is growing (13 % increase in mass).

The single hatchling is in an indoor 10-gallon aquarium with a slope allowing for variation in water depth (0-3/4"). One end is covered with an inch of live sphagnum the other is open water with a small cypress root separating the two sections. The tank is illuminated 24 hours a day with a full spectrum florescent light suspended 12 inches above the water surface and substrate. The room in which the tank is housed remains about 80-85 ° F. The hatchling spends 90% of its time in water, but beneath the sphagnum or the log. The remainder of time is invested in patrolling the open water. Within two days of hatching, it fed on small mealworms and mosquito larvae and pupae. Finely cut earthworms and fish pellets were initially refused. Like other first year Cuora maintained in adjacent tanks, it also probably selectively feeds on insects attracted to lights and subsequently fall into the aquariums.

This box turtle is but one of a number of highly endangered species of turtles indigenous to Southeast Asia . As part of a long-term conservation effort, members of the Asian Turtle Consortium are committed to captive management of Asian turtles. Through captive breeding, they hope to be able to maintain genetically viable stocks of species such as Cuora zhoui that have become highly endangered and, in a number of cases, extirpated from the wild. The Tortoise Reserve is one of the founding members of this private sector non-profit conservation organization. The Asian Turtle Consortium works independently of, but in cooperation with, all governmental agencies and other conservation groups. The 100-member organization oversees a composite collection of over 90 taxa of adult Asian turtles and annually produces thousands of young. Several programs are now in place where captive bred young are being returned to countries in Southeast Asia .

We thank the late Dr. Barbara Bonner of the Turtle Hospital , who accompanied the turtles when they were transported to the Tortoise Reserve. She is responsible for initially assessing and stabilizing their health and donated a number of the other turtles inhabiting the same enclosure. Mike Lowe, NC Vet School, has helped to oversee the health of the adults and hatchlings. Dr. Charlie Innis pit tagged, examined and medicated the turtles immediately after acquisition.  In June 2004 the greenhouse facility where these Cuora and other Asian turtles are maintained was named in honor of Dr. Bonner.

(Lee) The Tortoise Reserve, Inc. P. O. Box 7082, White Lake, North Carolina 28337 Torresinc@aol.com

(Levine) Asian Turtle Consortium, Board Chairmen, 1716 Beacon Street, Waban MA 02468 leslielevine@rcn.com