Survey finds around 180,000 Aldabra giant tortoises thriving on Seychelles atoll

A comprehensive survey conducted by the Seychelles Islands Foundation together with the University of Exeter has determined that approximately 180,000 Aldabra giant tortoises inhabit Aldabra Atoll, marking the highest count ever recorded for the species. The researchers examined five years of monitoring data from 2018 to 2022, updating the previously cited figure of 100,000 tortoises from the 1990s. Published in the journal Ecology and Evolution, the study estimates nearly 183,000 adult and sub-adult individuals and describes the population as relatively stable.

Conservation leaders attribute this success to decades of protection, including the atoll’s designation as a strict nature reserve in 1981 and a UNESCO site in 1982. Nonetheless, the authors caution that increasing droughts, sea-level rise, and invasive predators such as feral cats and black rats could threaten future growth, and they recommend eradication of these mammals to bolster resilience.