A remarkable conservation story is unfolding on a remote atoll in the Indian Ocean.
A new scientific study estimates that approximately 180,000 giant tortoises inhabit Aldabra, in the Seychelles. The findings offer encouraging evidence of long-term wildlife protection.
Once driven close to extinction by human exploitation, these ancient reptiles now form the world’s largest free-roaming giant tortoise population.
The research, conducted by the Seychelles Islands Foundation and the University of Exeter, provides the most reliable population estimate to date.
From Near Extinction to Conservation Success
During the 19th century, intensive exploitation devastated Aldabra’s giant tortoises (Aldabrachelys gigantea).
Historical accounts suggest their population fell below 1,000 individuals. Hunting and collection placed enormous pressure on a species already vulnerable to human disturbance.
Today, Aldabra presents a very different picture.
The atoll became a strict nature reserve in 1981 and received UNESCO World Heritage status in 1982. Decades of protection have helped secure its extraordinary biodiversity.
Researchers now estimate that roughly 180,000 giant tortoises roam its landscapes, from open grasslands to coastal vegetation.
Their survival represents one of the Indian Ocean’s most significant long-term conservation achievements.
What the New Study Actually Reveals
The research team analysed field observations collected between 2018 and 2022.
Scientists used advanced statistical models to estimate animals that survey teams may have overlooked in dense vegetation.
The resulting population estimate reached approximately 183,000 adult and subadult tortoises, generally rounded to 180,000.
Earlier estimates suggested around 100,000 individuals in the late 1990s.
However, researchers emphasise an important distinction: the population has not necessarily doubled over the past three decades.
Previous counting methods may have underestimated tortoises hidden beneath vegetation or resting in shaded areas.
The new modelling approach provides a more accurate picture of their abundance.
Crucially, the study found that the population remained relatively stable between 2018 and 2021.
That stability, supported by decades of protection, is itself encouraging news.
More Than Just Giant Tortoises
Aldabra’s giant tortoises play a vital ecological role.
As large herbivores, they influence vegetation, disperse seeds and help maintain the balance of the atoll’s terrestrial habitats.
Scientists describe them as ecosystem engineers because their feeding and movements help shape the environments around them.
Their ecological importance extends beyond the Seychelles.
Conservation projects elsewhere in the Indian Ocean have introduced Aldabra giant tortoises to restore functions once performed by extinct island herbivores.
Their survival therefore supports wider efforts to rebuild damaged ecosystems.
A Success That Still Needs Protection
Despite these encouraging findings, Aldabra’s future is not free from threats.
Climate change could bring increasingly severe droughts, reducing the vegetation and shade essential for tortoise survival.
Rising sea levels also threaten the atoll’s low-lying habitats.
Invasive species remain another concern.
Feral goats were successfully eliminated from Aldabra in 2012, allowing vegetation to recover.
However, feral cats and black rats continue to threaten tortoise eggs and hatchlings.
Scientists emphasise that continued monitoring and invasive species management remain essential to preserving this conservation success.
A Lesson in Long-Term Conservation
Aldabra’s story demonstrates something increasingly important in global conservation: protecting nature requires patience.
The recovery of a species cannot always be measured in months or years.
It may take generations of scientific monitoring, habitat protection and sustained commitment.
The new population estimate does not mark the end of conservation efforts.
Instead, it provides a valuable baseline for understanding future changes.
At a time when biodiversity loss dominates environmental headlines, Aldabra offers an encouraging reminder.
When habitats remain protected and conservation continues across decades, wildlife has a genuine opportunity to thrive.
Did You Know?
Giant tortoises help restore ecosystems by dispersing seeds through their droppings. On Mauritius, they contribute to the regeneration of native vegetation, including endangered ebony trees.
FAQ
A 2026 study estimates approximately 180,000 adult and subadult giant tortoises on the atoll.
The species is classified as Vulnerable on the IUCN Red List, despite its substantial population on Aldabra.
It supports the world’s largest free-roaming giant tortoise population and has enjoyed strict protection for decades.
Not necessarily. Improved scientific methods revealed animals that older surveys may have missed.
Climate change, prolonged droughts, rising sea levels and invasive predators remain major concerns.
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