NASA helps giant tortoises return to a Galápagos island
After 150 years, giant tortoises are back on Floreana! Watch as 158 tortoises take their first steps into the wild, guided by cutting-edge NASA data. Video via EarthSky.
NASA helps giant tortoises return to a Galápagos island
For the first time in more than 150 years, giant tortoises are roaming the wild again on Floreana Island in the Galápagos. On February 20, 2026, conservation teams from the Galápagos National Park Directorate and the Galápagos Conservancy released 158 tortoises at two sites. They chose those sites using NASA satellite data, identifying areas where the animals could easily find food, water and nesting locations.
Keith Gaddis, manager of NASA Earth Action’s Biological Diversity and Ecological Forecasting program, said:
This is exactly the kind of project where NASA Earth observations make a difference. We’re helping partners answer a practical question: where will these animals have the best chance to survive, not just today, but decades from now?
Giant tortoises: A history lost and found
Giant tortoises disappeared from Floreana in the mid-1800s. The Floreana giant tortoise went extinct due to a few reasons. First, sailors arrived and hunted the animals for their meat. The tortoises could be stored alive on ships for up to six months, providing fresh food in other locations. But sailors also introduced predators, such as pigs and rats, which preyed on tortoise eggs and hatchlings.
So, without the tortoises, the island began to change. Historically, giant tortoises helped shape the landscape. They grazed on vegetation, opening pathways through dense plant growth and carrying seeds.
The path to reintroduction began decades later. In 2000, James Gibbs, Vice President of Science and Conservation at the Galápagos Conservancy, and other researchers discovered unusual tortoises on Wolf Volcano in northern Isabela Island. They did not resemble any known living species.
About 10 years later, scientists compared DNA from these animals with genetic material from bones of extinct Floreana tortoises from caves and museums. The analysis confirmed some of the Wolf Volcano tortoises carried Floreana ancestry. These tortoises were a sort of hybrid. It seems as if the sailors, in moving the tortoises on their ships, at one point dropped some off on Isabela Island more than a century ago.
Scientists then used these hybrid tortoises to establish a breeding program. And it has produced hundreds of offspring that are now ready to return to Floreana.
Matching tortoises with the right habitat
Releasing tortoises into the wild is not as simple as opening a gate. Young tortoises raised in captivity must learn to find food, water and nesting sites. Gibbs said:
They don’t know where food is; they don’t know where water is; they don’t know where to nest. If you can place them where conditions are already right, you give them a much better chance.
Floreana’s terrain adds another layer of challenge. Some hills and mountains capture clouds and support cool, moist forests. Meanwhile, lower areas remain dry most of the year. Because tortoises need both food and nesting areas, they naturally migrate between these contrasting habitats. Thanks to NASA satellite data, researchers can identify the best release sites.
Using NASA data to guide release of giant tortoises
NASA satellite data play a key role in understanding these movement patterns. Observations track vegetation, rainfall, moisture and land-surface temperatures across the islands. Thus, the data highlight the areas most suitable for tortoises.
The project’s team, including professor Giorgos Mountrakis at the State University of New York College, created a decision tool. It combines satellite measurements with millions of field observations of tortoise locations. The tool maps habitat suitability today and predicts conditions decades into the future. This is crucial for an animal that can live over a century. Giorgos Mountrakis said:
This isn’t a one-year project. We’re looking at where tortoises will succeed 20, 40 years from now.
The scientists used various satellites in the project. They include Landsat and European Sentinel, which monitors vegetation, the Global Precipitation Measurement mission, which provides rainfall information, and Terra, which measures land-surface temperature. Also, teams used high-resolution commercial satellite imagery from NASA’s Commercial Smallsat Data Acquisition Program. All these data allowed them to evaluate potential release sites before conducting field surveys.
Christian Sevilla, director of ecosystems at the Galápagos National Park Directorate, said:
Habitat suitability models and environmental mapping are essential tools. They allow us to integrate climate, topography and vegetation data to make evidence-based decisions. We move from intuition to precision.
Restoring Floreana’s ecosystem
The tortoise release is part of the broader Floreana Ecological Restoration Project. This project focuses on removing invasive species such as rats and feral cats that threaten eggs and hatchlings. Eventually, the plan is that 12 native animal species will return, with giant tortoises serving as a keystone species to help rebuild ecological processes.
Over the past six decades, the Galápagos National Park Directorate has raised and released more than 10,000 tortoises across the archipelago. It’s one of the largest rewilding efforts ever attempted.
Each island presents unique challenges because of differences in vegetation, moisture and terrain. Combining long-term field observations with NASA data helps scientists anticipate how tortoises will interact with these environments. Plus, they can assess habitat changes forecast for decades ahead.
If successful, Floreana could once again support a thriving tortoise population. It could restore the interactions between animals, plants and landscapes that have shaped the island for thousands of years. Sevilla said:
For those of us who live and work in Galápagos, this release is deeply meaningful. It demonstrates that large-scale ecological restoration is possible and that, with science and long-term commitment, we can recover an essential part of the archipelago’s natural heritage.
Bottom line: Giant tortoises return to Floreana Island in the Galápagos. NASA satellites are guiding their release and helping revive the island’s wild ecosystem.
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