Hingeback Tortoises (Kinyxys)

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General

Most often called hingeback or hinged tortoises, the genus name of Kinyxys comes from two roots- kineo meaning ‘to move’, and ixus for waist or back. The exact number of species and sub-species varies depending on the source. Until 1981, only K. erosa, homeana, and belliana were recognized, then K. natalensis was added. Some of this controversy stems from the difficulty in telling some of the species and sub-species apart.

Hingebacks are famous and unique due to the ability to close the back part of the shell over their hind limbs, likely as protection from big cats and other powerful predators. Most species are considered at least threatened and several are very endangered. They are a significant food source in most of their range, some people using trained dogs to locate them. There is also pressure from over-collection for the pet trade and habitat loss.

They do not hibernate, but possibly aestivate or just rest in hot, dry weather.

Description

Depending on the species, they grow to 6 to 8 inches, 15-20cm for most, with the Serrated (Kinyxys erosa) reaching 12 inches, 30cm. The carapace colors, shape, and texture vary by species. Females often have more colorful shells. The carapace shape is interesting and distinctive. The shell slopes from a high point over the hips to a lower, flared area over the head and shoulders. The rear part of the carapace is serrated or toothed in most species, and is actually hinged between the 4th and 5th costals so it can close over the entire hind end, probably to protect the tortoise from large cats and other strong predators.

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(Photo from Jacqui Gibson showing how tightly the back can close over the hind limbs as shown from the bottom.)

The head and limbs are generally typical of a tortoise –elephant-like limbs with slightly flattened fore-limbs– but are longer and more slender. The limbs and shell shape give them a distinctive “walking downhill” look. No visible toes, but five toenails on each limb. The tail has a nail-like claw on the tip. The limb coloration is usually fairly solid, ranging from tan to nearly black.

Species information

  • Kinyxys belliana, Bell’s Hingeback Tortoise (Bell, 1831)
    • 8in/20cm. Colors vary widely but are generally based around tans, browns, and  yellows. Scutes are usually light in the middle and darker on the edges. Smooth, rounded scutes and shell. Marginals are smooth and not flared.
    • Sub-Sahara Africa in dryer savannah and forest often on the outskirts of rain forests. More active in the rainy season.
    • Can store water in anal sacs to help it survive dry periods.
    • Information from the ARKive and the Reptile Database
    • Sub-species include:
      • K. b. bellianaBell’s Hingeback Tortoise (Bell, 1831). East Africa- Somalia to South Africa
      • K. b. domergueiMadagascan Hingeback Tortoise (Vuillemin, 1972). Madagascar.
      • K. b. nogueyiWestern Hingeback Tortoise (Lataste, 1886). West Africa, Senegal to Central Repulic of Africa.
      • K. b. zombensisSoutheastern Hingeback Tortoise (Hewitt, 1931) East African coastal plain, Tanzania
    • K. erosa, Serrated or Forest Hingeback Tortoise (Schweigger, 1812)
      • 12in/30cm- the largest species. Gulars extend beyond the carapace. Smooth, rounded scutes and shell. More colorful with dark reds with the browns. Flared and toothed/serrated/jagged marginals.
      • Central and South Africa in moist forests, often found near water or marshes. Often discovered under logs or buried in roots. Excellent swimmer and known to hunt fish. Some consider it nearly semi-aquatic.
      • Tortoise Trust care sheet and info from the Reptile Database

108Photo from Jacqui Gibson showing a Forest from the side

    • K. homeana, Home’s Hingeback Tortoise (Bell, 1827)
      • 8in/20cm. The scutes tend to to be flat and meet each other at angles instead of being smoothly rounded. Tan to dark brown carapace with some yellow. Flared marginals.
      • Central and South Africa in moist forests, often found near water or marshes.
      • Information from the Reptile Database

001Home’s, showing hinge and rear. From Jacqui Gibson

    • K. lobatsiana, Lobatse Hingeback Tortoise (Power, 1927)
      • 6in/15cm. Long, narrow, slightly domed carapace. Similar enough to Bell’s that it was considered a subspecies.
      • Limited range in South Africa, Botswana in drier savanna or scrub forest.
      • Information from the Reptile Database
    • K. natalensisNatal Hingeback Tortoise (Hewitt, 1935)
      • Under 6in/15cm. Slightly domed back, fat on top and sloping on the sides. Yellow to orange on the centers of the scutes surrounded by brown or black.Marginals are not flared.
      • Limited range in southern Africa in dry, scrub forests.
      • Information from the Reptile Database
    • K. spekii, Speke’s Hingeback Tortoise (Grey, 1863)
      • 8in/20cm. Similar to Bell’s with a flatter carapace and more dramatic coloration much like the Forest.
      • South central Africa with habitat similar to Bell’s.
      • Was considered a sub-species of Bell’s until recently and is often still listed as K. belliana spekii.
      • Information from the Reptile Database

Reproduction

Courtship is fairly simple and generally involves nudging, pushing, or moving the female. If she stays, mating will occur. Because of the angle of the female’s shell the male may be at such an open angle that he may be unable to touch his forelimbs to the female’s back. Males often make groaning hisses and other noises during mating with one reviewer mentioning that they are the loudest species they have kept.

Eggs are laid in nests, which for some species may be piles of leaves. Rainy seasons probably trigger courtship and/or laying. Eggs are rather large and may benefit from the ability of the shell to flex during laying. A normal clutch is 2-4 eggs, although a large Bell’s may lay twice that many. Most species can produce multiple clutches in a year.

Hatchlings range 1.5 to 2 inches. Most species other than Bell’s have strongly serrated marginals (which may help with camouflage as well as making them harder to eat.) They do not hatch with the hinge and are often mistaken for young Homopus or Padloper Tortoises. The hinge appears at about 2 years old.

In captivity, the eggs should be incubated at 30 C for 3-4 months, although longer times seem normal in the wild. For more incubation and neonate help, see INCUBATION and NEONATAL CARE (but remember, they were written for Red-footed Tortoises.) There are two articles at Tortoise Trust: Bell’s and Forest.

Indoor housing

This is a very active group of tortoises, so aim for as much space as possible. 20 gallon tanks or tubs are the minimum for very young tortoises. 40 gallon tubs or tanks are OK for up to about 6″ long. 8′x4′ is suggested minimum for adults. Habitat should be waterproof and secure. Hides (leaf litter works well) and shelters are necessary. Live, “baby safe” plants are helpful but may be eaten or knocked over. Some commonly used substrates are mixes of sand, coconut coir, and/or clean soil. They like to dig in a little, so a deep substrate is recommended.

Outdoor housing

Outdoor pens should be very spacious, secure from escapes (these are excellent climbers!) and predators (or theft), and well-planted with vegetation they can eat and foods and plants they can hide under. Fresh water and hides are also needed. Piles of leaf litter, etc. make excellent hides for these species. If nights are below 60F, there should be a heated shelter. If the days are hot and/or dry, there should be a misting or sprinkler system available.

Environment

Warm (not hot), humid climate, although Bell’s, Natal, and Speke’s do not need such high humidities.

  • 70-80F preferred range. Can tolerate 60F lows short term and do not do well over about 90F. (Heating)
  • Most species need very high humidity (80-100%). High humidity hides and spaces may be OK if you cannot humidify the whole habitat. (Humidity) Artificial rain can stimulate appetite.
  • Gentle lighting with low-levels of UVB lighting are recommended. (Tortoises with regular access to unfiltered sunlight do not need UVB lighting.)

Water

A wide, shallow, easy-to-clean bowl of fresh water must always be provided. The bowl rim should be level with the substrate. These tortoises like to soak, so use a wide enough bowl to allow them to sit in the water.

Diet

A combination of plant matter, mushrooms. vegetables and fruits, and vertebrate or invertebrate protein. Prepared tortoise chows may be used instead or along with fresh
foods.

  • Plant materials can be dark leafy greens, such as collards or turnip greens, dark lettuces, spinach, dandelion, etc. Edible plant leaves and flowers, such as mulberry, grape, or hibiscus can be offered as well.
  • They eat mushrooms readily, moreso than most tortoises. Mushrooms offer fiber and wild mushrooms offer vitamin D (although store bought ‘shrooms may not.) Portabella and oyster mushrooms are the most nutritious; some keepers even avoid the white “button” mushrooms. Mushrooms can be up to almost 1/2 of the total diet.
  • Vegetables and fruits can include melon, shredded carrot, squash, pumpkin, bell pepper, apples, kiwifruit, etc. Some very good options are figs and papaya, especially if it is colorful! They seem to prefer some fruits a bit overripe. Keep bananas, grapes, and citrus to a minimum. This should be about 10-20% of the diet or so.
  • Meats should be about 10% (but can be more) of the diet. Live bugs and beetles, worms, snails and slugs, millipedes, lightly cooked eggs, chicken, “oily fish”(salmon, mackerel, etc.), dog or cat food and so on. They especially like worms, and some are known to actively hunt fish!

Feed daily. Remove food when it goes bad. One way to help prevent overfeeding is to limit the higher calorie foods (such as fruits and meats) to an amount smaller than the tortoise’s head.

Other

  • Hingebacked Tortoises are threatened or endangered in the wild. Whenever possible try to select a captive-bred animal. This will also reduce the parasite load that used to cause so many health issues.
  • Related to the above, wild-caught specimens should be seen by a vet to get proper treatment for parasites.
  • This is an interesting species that is considered by some to be a bit more challenging to care for, and sometimes considered a bit sensitive in captivity. Many captives do well for several years then suddenly decline. Parasite loads are one possible reason for this, but the high humidity needs and other care elements may be another.
  • They are a very territorial species and should not be mixed with other species, but several reports suggest they do best in groups.

Resources

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