Island reptiles are going extinct before we even knew they existed

Out of the roughly 12,000 species of reptiles known to science, about one-third live only on islands. Some are famous, like the Galápagos tortoise or the Komodo dragon. But most are small, quiet, and unknown.

Their homes – tropical islands, volcanic peaks, and remote archipelagos – cover less than 7% of Earth’s surface. Yet these spots pack in a huge chunk of global biodiversity.

Even with their importance, island reptiles are slipping through the cracks.

Extinction numbers don’t lie

Reptiles already have a hard time. They’re one of the most threatened groups of animals on the planet. But the numbers are worse for reptiles on islands.

A global study has recently revealed that 30% of island reptiles are at risk of extinction. That’s more than double the 12.1% average for all reptiles worldwide.

Since 1960, only 6.7% of reptile research has focused on island species. That means scientists are paying the least attention to the reptiles that need help the most.

Why if island reptiles disappear?

Reptiles are often keystone species. In simple terms, that means the whole ecosystem could fall apart if they vanish.

On Madeira Island, for example, wall lizards are everywhere. They chase bugs, pollinate flowers, and eat fruit.

“If island reptiles are allowed disappear, this would have huge impacts on many other species.” said Ricardo Rocha, associate professor of conservation science at the University of Oxford.

There’s also the problem of predators. Many island reptiles evolved without having to watch out for mammals. When humans brought animals like cats to these islands, the reptiles had no way to defend themselves.

“On Madeira Island, our research found that a single cat can eat more than 90 lizards in just one year,” Rocha explained.

“This makes them easy targets for predators such as free-ranging cats, which are a leading cause of extinctions on islands.”

The research gap is huge

The team behind the study looked at reptile research going back to 1960. They compared how much attention scientists give to island species versus mainland ones. They also looked at what kinds of reptiles get the most attention.

Turns out, bigger reptiles that live in more places get studied more often. Smaller species, ones that live at higher elevations or were discovered recently, tend to be ignored. Many live on just one island – and for a lot of them, there’s no research at all.

“Many of the world’s most distinctive reptiles – those that evolved in isolation on islands – are the least known,” said PhD candidate Sara Nunes from the University of Porto.

Some islands are hard to reach. Some reptiles aren’t seen as important or exciting. And in richer island countries, money often goes to tourism instead of wildlife research.

Some islands are packed with reptiles

Madagascar covers less than half of 1% of Earth’s land area, but it’s home to over 450 reptile species. That’s nearly 4% of all known reptiles on the planet.

One out of every four threatened reptiles on the IUCN Red List lives in Madagascar.

Another important spot is the Indo-Malayan region. It’s full of island reptiles yet barely studied at all.

In this region, the researchers found several high-priority species that live on just one island – and no one has studied them yet.

What needs to happen now

The scientists behind the study laid out a plan to fix the problem. First, they want to focus research on island reptiles that are most at risk and least known.

Second, the researchers are calling for more teamwork between island communities and national science institutions. Local people can offer insights that outside scientists might miss.

The experts also say that science needs to look beyond fancy journal articles. Reports from government agencies, NGOs, and community groups can help fill in the blanks.

Since a lot of research is written in languages other than English, translating those studies can give a clearer view of what’s happening worldwide.

Time is running out

From Anolis lizards in the Caribbean to giant tortoises in the Galápagos, island reptiles play a big role in the story of evolution. They’ve adapted to live in strange and specific ways. That makes them fascinating – but also fragile.

“As the biodiversity crisis deepens, understanding and protecting island reptiles has never been more urgent,” said Professor Rocha.

“Focusing scientific and conservation efforts where they are most needed – e.g., on islands and their unique reptile species – is essential to prevent irreversible losses. Imagine visiting Komodo Island and not seeing its dragons. It just wouldn’t be the same, would it?”

The full study was published in the journal Conservation Science and Practice.

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