There are more giant tortoises on one remote atoll in the Indian Ocean than there are people in the entire country of Seychelles. A new survey estimates about 183,000 adult and subadult Aldabra giant tortoises living on Aldabra Atoll, the largest population ever recorded for the species. The figure comes from five years of counting, careful statistical work, and – this is the best part – a conservation story that has been quietly working for more than four decades.
The survey was led by the Seychelles Islands Foundation, known as SIF, together with the University of Exeter, and published in the journal Ecology and Evolution. SIF staff collected the counts between 2018 and 2022, walking an atoll that most of the world will never see, tallying animals that can weigh up to 550 pounds and live well over 100 years. Some of the tortoises alive on Aldabra today were already old when the reserve protecting them was created.
From fewer than 1,000 to a record count
It is hard to overstate how close this species came to disappearing. In the 19th century, heavy exploitation cut the Aldabra population to fewer than 1,000 animals. Ships took tortoises in enormous numbers, and a creature that reproduces slowly had no way to keep up. For a long stretch, the future of Aldabrachelys gigantea, as scientists call it, looked grim.
Then the protection arrived, and it stuck. Aldabra became a strict nature reserve in 1981 and a UNESCO World Heritage Site in 1982. The last big threat on the ground, feral goats that competed with tortoises and chewed through the vegetation, was eradicated in 2012. None of that is glamorous work. It is patrols, paperwork, patience, and people showing up year after year. The 183,000 figure is what that patience looks like when somebody finally counts it properly.
Dr Frauke Fleischer-Dogley, chief executive of SIF, put it plainly: the result is proof of what long-term conservation commitment can achieve. She is right, and the word to underline is long-term. Nothing in this story happened fast.
An honest number, carefully counted
Here is the nuance, and it makes the result more credible, not less. The last atoll-wide estimate, from the late 1990s, put the population at about 100,000. The new figure is not proof the population suddenly doubled. The researchers are clear that better counting explains part of the gap: this survey used statistical modelling to account for tortoises hidden in thick vegetation, animals earlier methods simply missed. During the 2018-2022 study period itself, the population was relatively stable.
That honesty matters. Good science stories work the same way whether the subject is a tortoise count or a faint object in deep space – as with a lonely cloud that may be a galaxy with no stars, the excitement holds up because the researchers say exactly what they know and what they do not. The Aldabra team has now set the first rigorous modern baseline for the atoll. Every future count gets measured against this one, and that is a genuine scientific gift.
A workforce of counters who know every path
One detail in the study deserves more credit than it usually gets. The counts behind the headline were not gathered by a visiting team parachuting in for a season. SIF staff, based on the atoll year-round, collected them across five years, working through heat, rough ground, and vegetation thick enough to hide a 500-pound animal surprisingly well. That local knowledge is part of why the modelling works: the people feeding the data know which thickets a tortoise favours and which open flats empty out by midday. Long-running field stations rarely make headlines. Aldabra’s just produced the most important number in its species’ history, which suggests the model – protect a place, staff it properly, count honestly – deserves copying wherever a rare species still has a home range left to defend.
The tortoises run the place, in the best way
Aldabra’s tortoises are not just residents. They are engineers. By grazing, trampling, and moving seeds around in their droppings, they shape the atoll’s vegetation much the way elephants shape grasslands elsewhere. Whole communities of plants and smaller animals live in a world the tortoises maintain. Protect the tortoise, and you protect the system it runs.
There is a wider lesson here for anyone who follows health and science news, where careful measurement keeps rewriting what we thought we knew – the same spirit behind advances like Masimo’s FDA clearance for AFib detection. Count properly, protect patiently, and the picture changes.
What 183,000 really means
So what does a record count actually buy? Security, mostly. A population this size, on a protected and remote atoll, has room to absorb bad years, disease scares, and shifting conditions in a way a population of 1,000 never could. It also buys knowledge. Five years of structured counts, gathered by SIF staff who know the atoll path by path, now exist as a record that future researchers can build on for decades.
And it buys a story worth telling plainly. A species hunted down to a remnant now numbers about 183,000, not because of one dramatic rescue, but because people protected a place in 1981 and never stopped. The tortoises, famously, are in no hurry. It turns out conservation works best when people are willing to match their pace.
Be First to Comment