OBSERVATIONS ON SPEKE'S HINGED TORTOISE, KINIXYS SPEKII GRAY (CHELONII: TESTUDINIDAE)

Abstract

Eighty three Speke's hinged tortoise were studied by mark-recapture methods in the Boulton Atlantica Researeh Station, near Harare, Zimbabwe. The population was estimated to total 130 +/- 33 individuals, with an average density of 2.25 tortoises per hectare. The sex ratio was 2.6:1 F:M., but this may be biased due to increased female activity in open grassland during the wet season. Tortoises were fairly uniformly distributed over the study site, but there may be differences in seasonal habitat utilization by the sexes. Adult males may move from wooded grassland in the wet season to pure woodland during the dry winter. Females showed a similar trend, with a decrease in occurrence in open grassland between the wet and dry season. The diet comprised Hyparrhenia grass, with succulent and semi-suceulent shrubs and forbs, with occasional mahobohobo fruit (Uapaca kirkiana) and millipedes. Thirteen tortoises were recaptured a total of 19 times. The shortest movement was 80m, the greatest 820m; several exceed 500m. Tortoises were active between 07h00 and 17h30, with a peak between 11h00 and 14h00. During the dry winter some tortoises hibernated in old ant-bear burrows. Mating occurs between September and November, oviposition takes placed from November to mid-February (4–6 eggs, 30 × 38mm); hatchlings were found from November to April. Observed predators included Secretary birds and monitor lizards.