Why Aldabra’s Giant Tortoises Outnumber Seychelles Residents

A five-year survey puts the atoll’s free-roaming tortoise population at about 180,000, but the estimate is not a simple head count.

Nature & AnimalsOctober 10, 20263 min readHow Sureno writes this

The short version

A recent survey estimated about 180,000 Aldabra giant tortoises on Aldabra Atoll, a number reported as higher than Seychelles’ human population. ¹²
The estimate comes from five years of counts gathered by Seychelles Islands Foundation staff between 2018 and 2022, not from counting every tortoise at once. ¹²
It is the first atoll-wide estimate described as rigorous since a widely cited figure of 100,000 from the late 1990s. ²
The reported population was relatively stable during the survey period, so the new figure does not by itself show that numbers rose recently. ¹

How many giant tortoises live on Aldabra?

The latest estimate is about 180,000 Aldabra giant tortoises living freely on Aldabra Atoll, in Seychelles. The survey’s researchers say this is the highest figure recorded for the species and a population larger than the country’s human population. ¹²

Headlines have also used a figure close to 183,000. The supplied reports, however, describe the estimate as approximately 180,000. It is best to treat that as an estimate, not an exact tally. ¹²

How did researchers count so many tortoises?

The estimate was based on five years of tortoise counts collected by Seychelles Islands Foundation research staff on Aldabra, from 2018 through 2022. The team analysed those records to produce an atoll-wide population estimate. ¹²

That is different from finding and recording every animal in one sweep. The reports describe the result as the first rigorous atoll-wide estimate and the first update to the widely cited late-1990s figure of 100,000. ² The supplied summaries do not explain the statistical method in enough detail to describe how the researchers adjusted the counts.

Why is the population so large?

The sources establish that Aldabra now supports an exceptionally large free-roaming population, but they do not give a detailed account of the ecological reasons for its size. They also do not provide a year-by-year population history that would show when or how the estimate changed.

The new estimate is not, on its own, proof of a recent population boom. The Guardian’s report says the population was relatively stable during the period covered by the study. A comparison with the older figure is useful context, but the two estimates were made decades apart and should not be treated as a precise growth calculation. ¹²

How are Aldabra’s tortoises being protected?

The survey was led by the Seychelles Islands Foundation and the University of Exeter. SIF staff living and working on the atoll collected the monitoring data over successive years, according to the reports. That continuing work provides the records behind the population estimate. ¹²

SIF’s chief executive described the result as evidence of what long-term conservation commitment can achieve. The reports connect the survey to a recovery programme, but the supplied material does not list its specific actions, explain which measures had the greatest effect, or set out future plans. ¹

Where else do giant tortoises live in the wild?

The reports identify Aldabra Atoll as one of only two places where giant tortoises are found in the wild. The other is the Galápagos, where the population is much smaller, according to the coverage of the survey. ¹²

The Aldabra giant tortoise is identified as Aldabrachelys gigantea. It is native to Aldabra Atoll in Seychelles. ²³ The headline comparison with Seychelles residents refers to the tortoises on Aldabra, not to a census of tortoises across every island in the country.

What we don't know yet

The supplied reports do not provide the full statistical method or the uncertainty range around the approximately 180,000 estimate.
They do not give a detailed breakdown by age, sex, or location within the atoll.
The sources do not explain which specific conservation measures contributed most to the population’s condition or what threats and plans researchers expect to address next.

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Questions people ask

Are there really more tortoises than people in Seychelles?

The survey estimates about 180,000 free-roaming Aldabra giant tortoises, and reports say this exceeds Seychelles’ human population. The comparison is based on an estimate for the tortoises, not a count of every animal. ¹²

Is the Aldabra tortoise population 180,000 or 183,000?

The supplied reports describe the estimate as approximately 180,000. One headline uses a figure close to 183,000, but the reports do not explain a separate exact count at that level. ¹²

Did Aldabra’s tortoise population grow from 100,000 to 180,000?

The new estimate is about 180,000, while a widely cited estimate from the late 1990s was 100,000. Because the sources do not provide a comparable year-by-year series or details of both estimation methods, they do not establish an exact growth rate. ¹²

Who carried out the Aldabra tortoise survey?

The survey was led by the Seychelles Islands Foundation and the University of Exeter. SIF staff collected counts on the atoll between 2018 and 2022, which the team analysed for the estimate. ¹²

Where do Aldabra giant tortoises live?

The species’ native home is Aldabra Atoll in Seychelles. The reports also identify the Galápagos as the other place where giant tortoises live in the wild, with a much smaller population there. ²³

Sources

Scientists discover 180,000 giant tortoises on one Seychelles island — the Guardian, 2026-10-08
Giant tortoises outnumber people in Seychelles, with nearly 183,000 on Aldabra — Phys.org, 2026-10-07
Aldabra giant tortoise — Wikipedia

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