Serrated hinge-back tortoise (Kinixys erosa)

Also known as: eroded hinge-back tortoise, forest hinged tortoise
  
French: Kinixys Rongée, Tortue Articulée D'Afrique
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderTestudines
FamilyTestudinidae
GenusKinixys (1)
SizeLength: up to 37.5 cm (2)

Classified as Data Deficient (DD) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Hinge-backed tortoises (species belonging to the genus Kinixys) have the remarkable ability to shut themselves entirely within their shells (4). This is due to the hinge at the back of the carapace (or shell) that can close off the tortoise’s hind legs and tail (4). The serrated hinge-back tortoise has a slightly concave shell that is reddish-brown and yellow in colour (2) (5). The scales at the rear of the shell have upturned edges, giving, as the common name suggests, a serrated appearance (2). The head is rounded and the tail has a small, claw-like protuberance at the tip. Male serrated hinge-back tortoises can be distinguished from females by their longer and thicker tails (2).

Occurs in West Africa from the Gambia, east to the Democratic Republic of Congo and Uganda, and south to southern Angola (6).

The serrated hinge-back tortoise inhabits low to mid-altitude forest (2), where it is nearly always observed in shady areas (7). It is reportedly fond of swampy areas, but in Ghana occurs mostly in dry clearings and open areas (2).

The serrated hinge-back tortoise can often be found under logs, in holes or in leaf litter, where it uses its strong legs and upturned shell edges to wedge itself into a protected shelter (2). When in the open, the hinge-back tortoise can defend itself by withdrawing its limbs and closing its shell (2). By resting and moving in the shade, the serrated hinge-back tortoise avoids overheating in its hot, tropical environment (7). It is also a reasonable swimmer and will frequently seek out marshes and river banks in the forest (4).

Like all Kinixys species, the serrated hinge-back tortoise is omnivorous, and feeds on fungi, fruits, plant matter, invertebrates and even carrion (2) (8). During the breeding season it is thought that males fight (2), competing for females to mate with. Females lay several clutches of four eggs on the ground and cover them up with leaves (2) (4). The sex ratio is close to 1:1, and females grow to a larger size than males (9).

Hinge-back tortoises are actively hunted by humans in sub-Saharan Africa, mainly for domestic consumption (9) (10). The flesh is highly prized as food by some forest peoples, and hunting is often carried out by dogs which locate the tortoise by its distinctive smell (2). The species is also vulnerable to habitat fragmentation in parts of its range (for example, in south-eastern Nigeria) (9), but appears to still be relatively widespread in the central African forests. Thus, it is possibly not particularly vulnerable to the impacts of habitat destruction at a large scale (2) (11).

Whilst in some areas the serrated hinge-back tortoise is hunted, in others this tortoise is worshipped by local communities. They believe it brings happiness, is a symbol of peace and a sign of abundant children (10). This ‘holy’ status may afford some populations a degree of protection. The serrated hinge-back tortoise is listed on Appendix II of he Convention on International Trade in Endangered Species (CITES), meaning that international trade in this tortoise should be carefully monitored to ensure it is compatible with its survival (3). However, as there is insufficient information to determine the status of the hinge-back tortoise in the wild (1), it can not be determined if the tortoise is being taken from the wild at sustainable levels. Therefore, further research and surveys are required to ensure that this trade is not putting the serrated hinge-back tortoise at risk of extinction.

For more information on tortoises and turtles and their conservation, see:

Authenticated (06/08/09) by Dr Luca Luiselli, Senior Researcher in Ecology, Institute Demetra, Rome, Italy.
http://www.intecol.net/pages/002_personal.php?id=lucamlu

  1. IUCN Red List (September, 2007)
    http://www.iucnredlist.org
  2. Spawls, S., Howell, K., Drewes, R.C. and Ashe, J. (2004) Field Guide to the Reptiles of East Africa. Christopher Helm Publishers Ltd, London.
  3. CITES (October, 2007)
    http://www.cites.org
  4. Burnie, D. (2001) Animal. Dorling Kindersley, London.
  5. Alderton, D. (1988) Turtles and Tortoises of the World. Blandford Press, London.
  6. Ernst, C.H., Altenburg, R.G.M. and Barbour, R.W. (1997) Turtles of the World. ETI Information Systems Ltd, Netherlands. Available at:
    http://ip30.eti.uva.nl/BIS/turtles.php
  7. Luiselli, L. (2005) Aspects of comparative thermal ecology of sympatric hinge-back tortoises (Kinixys homeana and Kinixys erosa) in the Niger Delta, southern Nigeria. African Journal of Ecology, 43(1): 64 - 69.
  8. Luiselli, L. (2003) Seasonal activity patterns and diet divergence of three sympatric Afrotropical tortoise species (genus Kinixys). Contributions to Zoology, 72(4): 211 - 220.
  9. Luiselli, L., Politano, E. and Akani, G.C. (2003) Seasonal incidence, sex-ratio, and population cohorts of hinge-back tortoises (genus Kinixys) in the wild and in bush-meat markets of the Niger Delta, southern Nigeria: are human predation effects random?. Revue de Ecologie - La Terre et la Vie, 58: 243 - 248.
  10. Luiselli, L. (2003) Comparative abundance and population structure of sympatric Afrotropical tortoises in six rainforest areas: the differential effects of “traditional veneration” and of “subsistence hunting” by local people. Acta Oecologica, 24(3): 157 - 163.
  11. Luiselli, L. (2009) Pers. comm.