Tortuga Gazette 30(1) 1-3, January 1994

Western Hinge-back Tortoise,
Kinixys belliana nogueyi

by Lisa Morris

Kinixys belliana nogueyi occurs in tropical western Africa. It is a small tortoise (up to 22 cm long) and differs from the other members of the Kinixys genus in having only 4 claws on the front feet. Its shell is rather tubular in shape, and may be a uniform yellowish brown color or have an attractive dark brown pattern somewhat similar to that of the pancake tortoise.

The genus Kinixys is unique in the turtle world in that it is the only genus in which a hinge is found on the carapace. This hinge enables a "hinge-back" to close down the rear of its shell to protect itself from predators. The hinge is not present at hatching, but only develops as the tortoise matures. The anterior marginal scutes are also quite elongated, allowing the tortoise to withdraw its head quite far back into its shell.

We currently have four adult Kinixys belliana nogueyi, 1 male and 3 females. They are wild caught specimens. All of them were heavily parasitized with both ecto- and endo-parasites when they were acquired and we took aggressive measures to treat them. The tick removal was easy but the various internal parasites required several rounds of treatment to bring them under control. Medicating by gavage was a very tedious and frustrating process because the tortoises were shy and stayed deeply retracted in their shells. After parasite suppression was finally accomplished, the tortoises seemed to feel better, becoming more active and spending less of their time withdrawn into their shells. We feel that without treatment, these animals would most certainly have died.

When we first acquired our hinge-backs, we kept them indoors in a 150 gallon aquarium with a damp newspaper substrate to facilitate easy cleaning and cleanliness. The glass lid was closed except for a crack, and this kept the humidity high (90-100%). A 4' Vitalite provided a 12 hour light/dark photoperiod. During the winter, a Chromlux 60 watt light bulb with a Microclimate thermostat set at 82°F was used as a supplementary heat source during the day. At night, the temperature dropped to that of the house. The average temperatures were 80°-85°F during the day and 68°-72°F at night. Occasionally, the interior of the vivarium became wet, so we would open the top and let it dry out. The tortoises would then become completely inactive until we "made it rain" by pouring in water from a watering can. There would then be a frenzy of activity. For the most part though, our tortoises tend to be some what reclusive, regularly spending days at a time in their hide-box before coming out to eat. This behavior has also been reported from the wild. When they are active they spend much of their time soaking and defecating in their water dish. The females will occasionally get into short shoving matches or bite off each others' rear toenails.

We currently keep the hinge-backs in a greenhouse. Their area is 2' x 11' with a 2' x 3' sleeping area that they are closed into at night. The sleeping area has a concrete floor covered with a Stanfield Hog Heating pad attached to a temperature controller. The air temperature in the sleeping area is maintained with a space heater set at 82°F, and a fogger system maintains the humidity in both the greenhouse and the sleeping area. The air temperature inside the greenhouse reaches 100°F regularly. The ground, however, stays cooler and there is always shade available. An evaporative cooler comes on when the temperature goes over 100°F to prevent overheating.

Hinge-back tortoises seem quite omnivorous. We feed fruit, vegetables, grass and clover clippings, mealworms and, occasionally, soaked Zu-Preem or Purina trout chow. We supplement the diets of both the adults and the neonates with a light sprinkling of Super-Preen powdered vitamins and calcium at least once a week. They often pick at their food unless it is mealworms or watermelon, their favorites. We have observed them eat out the inside of half a watermelon, then crawl inside the empty rind to sleep!

Our tortoises mate most heavily from June to November, but occasionally at other times throughout the year. In about May, before the mating season really starts, the females will attempt to "mate" with one another. This female-female "mating" behavior includes mounting and is accompanied with the issuance of mating sounds similar to those made by the male.

Our male begins to mate in June. He mounts a female, wraps his long tail under hers, gapes his mouth, drools, and emits a series of wheezing honks, not unlike the sound of a person blowing his nose in a handkerchief. Our females tend to be very cooperative with the male, allowing him to successfully copulate frequently.

The females become restless in the fall, literally "climbing the walls" in the weeks before they lay, which is from late November to January. Last year, three clutches of oval brittle-shelled eggs were deposited on the damp newspaper substrate. Clutch sizes ranged from 2 to 5 eggs. Egg size ranged from 33 mm long and 28 mm wide to 43 mm and 30 mm wide with the smaller clutches usually having larger eggs. The eggs were placed into our home-made incubator, a Sears Coldspot upright freezer box with heat tape placed in the bottom thermostatically set at 86°F. The eggs were incubated in damp vermiculite in plastic sweater boxes. The incubation periods ranged from 148 to 172 days with an average of 144 days. The hatchlings were circular in shape and were folded inside the eggs. The deep crease in the plastron disappeared after a few days. Some of the hatchlings were deformed and subsequently died. We feel the deformities were caused by too high an incubation temperature. This year we are incubating the eggs at 84°F.

The four normal neonates ate after 1 week. The first thing we offered them was soaked Zu-Preem covered with mango puree. The bright color and strong aroma of the mango seemed to stimulate them to feed. Now, they eat almost anything and seem eager to try new things. They are now fed the same diet as the adults, but their favorite food is mealworms. The hatchlings were very aggressive towards each other, ramming and biting at each other's feet and heads. After several of the hatchlings received lacerations to their necks each was placed in a separate vivarium: a tall sweater box with moistened newspaper as substrate and over which is placed a piece of "plastic canvas", a lightweight plastic mesh used for crafts. A Vitalite is used as the light source, a plastic cup is a hide box, and a plastic lid is a water dish. We soak them in shallow lukewarm water regularly. These hatchlings have a wonderful outgoing personality much in contrast to their shy, reclusive parents.

Bibliography

Ernst, C. H. and Barbour, R. Turtles of the World. Smithsonian Institution Press, Washington D.C., 1989.
Bertram, B. C. R.: Home range of a hinge-back tortoise in the Serengeti. African Journal Ecology 17:241-244, 1979.