In news that will delight tortoise enthusiasts and terrify anyone who prefers their islands shell-free, a new survey has found that approximately 180,000 Aldabra giant tortoises are living on Aldabra Atoll in Seychelles. That's the highest figure ever recorded for the species, and it comfortably exceeds the human population of the entire country - a fact the tortoises have yet to comment on, presumably because they're too busy being enormous and slow.

The survey, led by the Seychelles Islands Foundation (SIF) and the University of Exeter, analysed five years of tortoise counts between 2018 and 2022. It's the first update since a widely cited figure of 100,000 tortoises from the late 1990s, meaning the population has apparently nearly doubled while nobody was looking. The study, published in the scientific journal Ecology and Evolution, found the population was relatively stable during this period, with a best estimate of almost 183,000 adult and sub-adult tortoises.

Aldabra Atoll is one of only two places in the world where giant tortoises are found in the wild, the other being the Galápagos, which hosts a much smaller population. So if you're a giant tortoise looking for a lively social scene, Aldabra is the place to be.

Dr Frauke Fleischer-Dogley, CEO of SIF, said: "More than 180,000 giant tortoises roaming freely on our atoll is proof of what long-term commitment to conservation can achieve. This is wonderful news for Seychelles, for the world, and for everyone who has worked to protect Aldabra." That's a lot of shelled gratitude.

The tortoises haven't always had it this good. In the 19th century, exploitation of the animals meant there were fewer than 1,000 Aldabra tortoises left on the island. A recovery programme led to it becoming a strict nature reserve in 1981 and a Unesco site in 1982. Researchers now call it one of the greatest conservation success stories of the Indian Ocean - a region not exactly known for its abundance of good news.

"Aldabra's giant tortoise monitoring programme is one of the longest running in the region, but the atoll's dense vegetation makes counting tortoises genuinely difficult in places," said Dr Nancy Bunbury, one of the study's co-authors. "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." So the next time someone asks how many tortoises you saw, you can confidently say "at least some, and statistically probably more."

Despite the good news, the study's authors say vigilance is essential. Aldabra's climate is changing, with longer and more frequent droughts predicted to reduce the shade and food available to tortoises, while rising sea levels threaten low-lying parts of the atoll. Invasive mammals - including feral cats and black rats that prey on tortoise eggs and hatchlings - remain a threat. The planned eradication of these invasive mammals, the authors say, could lift the last barriers to further growth and help the population withstand future climate pressures.

"These results are great news for the tortoises and testament to the fantastic work done in the field," said Dr Dave Hudson, a postdoctoral research associate at the University of Exeter's Cornwall campus. "But it's important to remember that the numbers provide a baseline - not an endpoint. Hopefully we have provided the conservation managers the evidence they need to track future change and act early as the tortoises face increasing pressures from climate change, drought and invasive species."

So there you have it: 180,000 giant tortoises, one island, and a cautionary tale about celebrating before the climate crisis has had its say. The tortoises, for their part, remain stoically unbothered - as is their way.