The Indian Ocean giant tortoise Testudo gigantea on Aldabra
Article first published online: 20 AUG 2009
Journal of Zoology
Volume 154, Issue 3, pages 341–363, March 1968
How to Cite
Gaymer, R. (1968), The Indian Ocean giant tortoise Testudo gigantea on Aldabra. Journal of Zoology, 154: 341–363. doi: 10.1111/j.1469-7998.1968.tb01668.x
- Issue published online: 20 AUG 2009
- Article first published online: 20 AUG 2009
- Accepted 8 August 1967
The Indian Ocean giant tortoise survives on Aldabra, an atoll north-west of Madagascar. The Bristol Seychelles Expedition estimated the total numbers as 33,000 during visits in 1964 and 1965. Growth and movements were recorded during marking experiments. The growth rate with size is plotted, the time scale being derived from the number of rings on the shields of the shell; and the growth curve is compared with that for captive tortoises.
Variation in many characters of supposed taxonomic value is explained as the influence of environmental factors on the normal growth pattern, and of non-adaptive differences expressed during adult life. The present separation of north and south Aldabra, and Seychelles forms is not supported.
An explanation is suggested for the uniformity of shape among tortoises.
Observations were made on the feeding, diurnal movements and mortality of tortoises on Aldabra.