Aldabra’s giant tortoises reach 183,000, surpassing Seychelles’ human population
A survey by the Seychelles Islands Foundation and the University of Exeter estimates about 183,000 adult and subadult Aldabra giant tortoises on Aldabra Atoll, more than the Seychelles’ roughly 122,000 to 123,000 people. Researchers say the figure is not evidence of a sudden population jump: improved modelling accounted for tortoises missed in earlier counts.
Bottom line — The 2018–2022 survey provides a new baseline as drought, rising seas and invasive mammals remain threats.
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Researchers analysed five years of monitoring data collected between 2018 and 2022.
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Earlier estimates put the tortoise population at about 100,000 in the late 1990s; dense vegetation and shade made animals difficult to spot.
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Heavy hunting left fewer than 1,000 tortoises on Aldabra in the 19th century.
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Aldabra became a strict nature reserve in 1981 and a UNESCO World Heritage site in 1982.
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The study found the population relatively stable during the survey period.
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Longer, more frequent droughts could reduce food and shade, while rising seas threaten low-lying habitat.
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Feral cats and black rats prey on tortoise eggs and hatchlings.