Science & Tech · Science & Environment · 2 days ago
Aldabra Giant Tortoises Reach an Estimated 180,000 in the Seychelles
A survey estimates that about 180,000 Aldabra giant tortoises live on Aldabra Atoll in the Seychelles.
The estimate comes from the first rigorous, atoll-wide count since the late 1990s.
In the 19th century, hunting by sailors had reduced the population to fewer than 1,000.
Aldabra became a strict nature reserve in 1981 and a UNESCO site in 1982, helping the tortoises recover.
The new figure does not mean the population has nearly doubled since the last survey, because earlier counts likely missed animals hidden by dense vegetation.
The tortoises now outnumber people in the Seychelles, but they still face threats from drought, climate change, and invasive cats and rats that eat their eggs and hatchlings.
Researchers say the estimate provides a baseline for tracking future changes and guiding conservation.
A survey estimates that about 180,000 Aldabra giant tortoises live on Aldabra Atoll in the Seychelles, more than the country’s human population.
The atoll-wide estimate is the first rigorous one since the late 1990s and is based on counts collected between 2018 and 2022.
Researchers say the population was relatively stable during the survey period, with a best estimate of almost 183,000 adult and sub-adult tortoises.
The tortoises were reduced to fewer than 1,000 in the 19th century by heavy exploitation and overhunting.
Conservation measures, including making Aldabra a strict nature reserve in 1981, have helped the population recover.
Researchers say climate change, drought and invasive species remain threats.
- Who
- Aldabra giant tortoises on Aldabra Atoll. The survey was conducted by a team from the University of Exeter and the Seychelles Islands Foundation Aldabra.
- What
- A new survey estimates about 180,000 tortoises live on the atoll, more than the Seychelles’ human population.
- When
- Counts were collected between 2018 and 2022. The study was published in October 2026.
- Where
- Aldabra Atoll in the Seychelles.
- Why
- The survey provides a more reliable baseline for tracking the population. Researchers say conservation measures have helped the tortoises recover from past overhunting.
This story does not have two clearly opposing sides.
More than 180,000 giant tortoises roaming freely on our atoll is proof of what long-term commitment to conservation can achieve
By modelling what we didn’t see, as well as what we did, we’ve produced the most reliable baseline yet for this iconic Seychelles species, establishing a benchmark we can use to track the population for decades to come.
It's important to remember that the numbers provide a baseline – not an endpoint
European explorers and other seafarers began arriving in the Seychelles, and tortoises were taken for food.
Heavy exploitation and overhunting reduced the tortoise population on Aldabra to fewer than 1,000.
Aldabra became a strict nature reserve to support the tortoises’ recovery.
Aldabra was named a UNESCO site.
Researchers collected tortoise counts for the atoll-wide survey.
The survey findings were published in Ecology and Evolution.
- Estimated population
- About 180,000 tortoises
- Best estimate
- Almost 183,000 adult and sub-adult tortoises
- Survey period
- 2018–2022
- Historical low
- Fewer than 1,000 tortoises in the 19th century
- Protected status
- Strict nature reserve since 1981; UNESCO site since 1982
Sources
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