The Unnatural Evolution of the Galápagos Islands

Sunrise over the lava flows on Bartolomé Island, Galápagos, Ecuador. Michael S. Nolan / Science Source

Humans are forever altering these mythical islands through unnatural selection. Rewilding them entails finding a delicate balance between the needs of turtles, tourists—and local residents.

Snow is falling over the shell of a giant Galápagos tortoise as it sits regally on a volcanic rock next to a land iguana and the red-puffed pouch of a frigatebird. The flurries surrounding them are tinted gold, not because of a natural phenomenon—it’s early spring in South America—but because I’m watching these famous endemic animals in a snow globe that my ten-year-old son has shaken up, made in China, for sale for $8 in a tourist shop. The shop fills a corner of Charles Darwin Avenue in Puerto Ayora on Santa Cruz island, a hub of backpackers, day trippers and high-end eco-tourists who have come from around the world to see these animals in the wild of the mythic laboratory where Darwin formed his theory of evolution. 

As we drive down the avenue in our pickup truck taxi cab, we pass by scattered restaurants and stores selling everything from bikini tops patterned with blue-footed boobies, another one of the famous birds, to tortoise earrings decorated with Swarovski zirconias. The paved road winds into a dirt path where taxi cabs stop. No cars are allowed inside the property of the Charles Darwin Research Station to protect the crossing iguanas. Near the entrance stands a tall sculpture of a water bottle constructed by local artists from plastics and a sea lion made from flip-flop soles with a bottle top tortoise shell sitting at its base. A sign announces that eight tons of plastic washed up on Galápagos beaches in 2019, often carrying invasive marine species. The impact of plastic on the archipelago’s ecosystem, along with the thousands of species that catch rides on visiting boats, is now the primary focus of this scientific center, where scientists work to continue and preserve Darwin’s legacy. After all, creatures floating on pieces of wood are how the famous animals arrived millions of years ago. 

A few hours earlier, I took a flight with my son and family friends from Quito, Ecuador, six hundred miles west to Baltra Island, where daily flights deliver tourists from around the world. As we descended to Baltra, flight attendants sprayed from cans of insecticide and filled the cabin with a smoky mist to kill invasive insects and diseases. I lifted my window shade to a view of hundreds of boats dotted around turquoise bays and overheard a mother behind me whisper to her young son to turn off his screen to focus on nature, to which he screamed in protest: “But the Bishop of Panama called it a hell on Earth!” A true statement made by Bishop Fray Tomás de Berlanga, referring to the archipelago’s arid and ominous black volcanic landscape, when he first discovered them in 1535. They looked this way because millions of years ago, the islands were formed by the layering and lifting of shifting tectonic plates that caused volcanic eruptions in which molten lava cooled to form this archipelago of 127 islands straddling the equator. We have joined other scientific-minded eco-tourists, aching to get back out into the world after two years of pandemic isolation. They are dressed in windbreakers and sensible hats, with carry-on bags embroidered with Amazon butterflies slung over their shoulders. They travel in search of pure nature and rare animals, and they carry the animal inspiration souvenirs they bought to bring home: a snow globe, tortoise-shaped chocolates, and of course, one of the ubiquitous joke T-shirts that say, I love boobies.

The Galápagos tortoise. Shutterstock /

Inside the research station, I walk past a breeding center where tiny baby tortoises circle a saltwater pond, past research buildings where these days scientists are focused less on the natural selection as the unnatural—the impact of climate change, plastics, and both marine and terrestrial invasive species transported from the outside world. The goal is to better understand the anthropogenic influences rapidly overtaking the natural forces that have traditionally evolved the islands. While only 3 percent of the Galápagos are populated and accessible by tourists, their impact has nevertheless been enormous. Because of human influence, many animals have gone extinct or are threatened with extinction, including two kinds of tortoises. The presence of humans is quickly turning this island paradise from a laboratory of endemic species into a laboratory of invasive ones. 

Trouble in paradise

A 2017 study by the Charles Darwin Foundation found 1,579 invasive species in the Galápagos Islands, of which 98 percent are recent transplants, arriving with humans since the 1970s when the Galápagos first became a tourist destination. 

In the 19th century, the isolation of these islands made them the perfect discovery lab. Darwin could observe genetic changes in different creatures, like the shapes of the shells of tortoises and the beaks of mangrove finches and mockingbirds, based on the different food and ecosystems of the individual islands. Yet throughout the islands’ history people have come, including British explorer Captain James Cook, whalers, Herman Melville, misfit naturalists, and Europeans escaping World War I. They visited these desolate islands as a last refuge and a place of inspiration—and changed them. In his 1984 dystopian comic novel Galápagos, about a human colony that repopulated the islands after a meteorite hit the earth, Kurt Vonnegut referred to us modern thinkers, poking fun at our hubris and impact, as living in “the era of big brains and fancy thinking.” 

“We are not on a biological island anymore.”

Today, one of the primary research focuses of the Charles Darwin Foundation is to study the impact of people, invasive species, and global tourism, which is responsible for supporting eighty-five percent of the economy of the islands. Darwin’s famed mangrove finches are at risk of extinction because invading flies from other South American countries infest their nests and kill their chicks. The invasive blackberry, originally from Southern China, is degrading the Scalesia forests with its brambles. And the rats—oh the rats! Stowing away in the bowels of ships, the rats hop off the boats here like any other tourist. They scurry, they scavenge, they cause chaos, and they have quickly driven to extinction thirteen species on Floreana Island, including the mockingbirds that were so instrumental in Darwin’s evolution theory. Despite strong controls by the Galápagos Biosecurity Agency, which closely inspects all boats coming into the ports, invasives still find their way onto the islands. 

“We’re on a geographical island, surrounded by the ocean, but we are not on a biological island anymore,” says Sharon Deem, sitting at a table outside one of the offices of the research station overlooking Charles Darwin Bay. A marine biologist walks by our interview and notes how “crazy” the weather is for this time of year. “The sea is warmer than the air right now,” she says, “which is unusual!” 

Marine iguanas congregate around a poignant message for toursists visiting the islands. Rafael Idrovo Espinoza

The tortoise-tourist complex

Deem is a brassy forthright zoologist with the Saint Louis Zoo. She works in the research center’s Galápagos Tortoise Ecology Program, studying the impact of climate change and the health of the tortoise population. She explains that invasive blackberries in the highlands of Santa Cruz have created barriers to the tortoise’s migration routes, which could change the health of the ecosystem. Galápagos tortoises are known as “ecosystem engineers” because they spread seeds through their poop and change the layout of the land by making tracks and eating vegetation. They are also one of the main draws for tourists, so their health is intimately tied to the local economy, and maintaining their populations is critical to maintaining the island’s ecological appeal, its influx of tourists, and its financial health.

Simultaneously, the invasive blackberry has forced many local farmers to consolidate their land  and raise cattle and poultry closer to the native tortoises. Last year, Deem’s team used molecular diagnostics to extract DNA from tortoises living in the highlands. In it, they found new antibiotic resistance genes and two novel sequences of adenoviruses and two unexpected herpes viruses. The team at the Charles Darwin Research Station wonders whether these viruses could be transmitted between wildlife and domestic animals.

The giant tortoise monitoring project and other studies run by the research station are informed by a concept known as One Health, which is the idea that human health is intimately linked to environmental and animal health. Since humans are also susceptible to many of the same pathogens as non-human animals, and since six out of every 10 cases of infectious diseases come from animal sources, Deem worries about the potential human impact of her team’s findings. “I mean, COVID-19 most likely spilled over because of our unnatural relationship with nature and with placing different animal species together that aren’t naturally together,” she says, referring to the theory of the bats infecting exotic animals that were later sold in wet markets in China.

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If the ecosystem is the immune system of the Earth, right now the Galápagos immune system is in peril due to these forces of unnatural selection. A well-known study found that human activity in Puerto Ayora between 1964 and 2005, when Galápagos tourism began to peak, caused ground finch’s beaks to get larger over a few generations because they began to eat larger crumbs dropped on the ground by tourists. On many other islands, the parasitic flies have killed off the vermillion flycatcher, and invasive rats caused the Floreana mockingbird to go extinct by gobbling up their eggs. “Invasive species have been rapidly increasing in recent years and have already been described and identified as major drivers for extinctions,” María José Barragán tells me on the phone a few weeks earlier. She is the science director at the Charles Darwin Research Station.

When Darwin first introduced his theory in On the Origin of Species, he wrote that extinction was natural and deeply connected to evolution. “The appearance of new forms and the appearance of old forms,” he wrote, “were bound together” by struggles for existence. We’re now living in Earth’s sixth extinction period, but what makes this one different is that the rate is much faster than ever because of us. “The Galápagos system is rapidly changing, and we are not responding fast enough as it has become more connected with a mobilized world system,” said Barragán. And these changes are part of a growing trend in biodiversity hot spots like Madagascar, the Seychelles, and the Hawaiian Islands. “This expansion of species is what we watch for around the world now because it’s one of the signature elements of climate change,” says Jim Carlton, a professor at Amherst University in Massachusetts who since the 1960s has been studying the introduction of non-native species through human activity . 

Rewilding Floreana

Just as humans and our “big brains” are hurting the Galápagos, we are also using our “fancy thinking” to fix the damage. Darwin formed his theory of natural selection more than 100 years before Francis Crick and James Watson discovered the structure of DNA, the molecule of evolutionary change. Now our modern understanding of genetics is helping scientists to try to evolve the islands for the better. 

“If we can’t understand these interactions in the birthplace of natural selection, then we’re pretty screwed.”

Deem points to Floreana Island, just to the south of us. In 2021, Re:wild, an organization whose purpose is to restore disappearing biodiversity across the globe, launched a pilot program working with the Galápagos National Park,, the nonprofit Island Conservation, and the local community of the island to restore its ecosystem to how it looked when Darwin first saw it. The actor Leonardo DiCaprio has made it his personal mission to support the effort. He has invested $42 million to expand the program to other islands over the next decade. The plan is to remove invasive species, halt extinction threats, and use genetic technologies to recover extinct species and reintroduce them. “The Galápagos is a microcosm of the world,” Deem says. “If we can’t understand these interactions in the birthplace of natural selection, then we’re pretty screwed.” 

The next day, our crew is crammed into a dilapidated fishing boat, a cruddy weatherworn tramp that seems undeserving of her name, Queen Astrid. We are on a day trip to the island Floreana, to see this project underway. After two hours on turbulent waves, fighting for space with a hard-headed group of deep-sea divers from Utah, we disembark in Post Office Bay. Floreana is the smallest of the inhabited islands of the Galápagos, with a sparse population of farmers and a few scattered restaurants and hotels serving day trippers and dive tours. The island also has the most endemic species in the archipelago because as it is one of the oldest islands, it is furthest away from the volcanic hotspot.

After a biosecurity inspection of our backpacks, we walk onto a black sand beach covered with primeval land iguanas and sea lions. We board an open-air bus that takes us into the greener highlands of the island. Feral chickens run in the middle of a dirt road lined with guaba trees dangling Jurassic-sized bean pods, known as ice cream beans because of their sweet pulp. Cactus plants are bursting their bright spiky yellow fruits in the equatorial sun. 

As we ascend to the base of Cerro Olympus the forest becomes much more lush. We get off the bus, and our guide, a rough-and-tumble 40-something man named Luis, with a theatrical manner, directs us to a path winding through the forest. We watch aloof tortoises gnawing on cactus leaves. He points to a freshwater spring that is the source that historically drew so many people to settle on the island—it’s one of the few islands with fresh water. He then offers an animated description of the illustrious history, which included stints as a prison colony and as island muse to Charles Darwin. This is where he first learned from locals that tortoise shell shapes differed on each island. In the 1920s and 1930s, a misfit German holistic doctor escaped the bustle of Berlin with his paramour to settle on the uninhabited island in pursuit of his personal “Garden of Eden.” They were soon followed by a self-described European baroness whose mysterious disappearance became the subject of the documentary The Galápagos Affair, which stars Cate Blanchett reenacting the role of the baroness. 

As we walk along a path past pirate caves and a large face sculpted into a rock, I notice a distinct absence of birds, and later I learn that the island has the highest rate of local extinctions of any island in the archipelago. Thirteen species, including the mockingbird, the Galápagos hawk, and the vermillion flycatcher, have gone locally extinct. And the Floreana tortoise has completely died out because whalers hunted them to eat on their long voyages, so the tortoise we were looking at in the forest had been imported from other islands. 

The rewilding project is on the verge of changing the island. It began with eradicating the invasive rats, and now conservationists are slowly reintegrating native species. In 2015, a team of scientists discovered a distant relative of the Floreana giant tortoise on Isabela Island by extracting DNA from its bones. They surmised that a whaling ship stashed with tortoises for food sank near Isabela Island, the tortoises escaped and began breeding with another species living on Isabela. The baby tortoises in the breeding center at the Darwin Research Station are part of a program in which biologists preserve the Floreana tortoise’s lineage by identifying the genomes of their closest relative on Isabela and breeding them. 

A vermillion flycatcher perches on Santa Cruz Island. Danita Delimont / Alamy

“We analyzed [their DNA] and looked for a high proportion of genes from the closest relative to the extinct tortoises,” explains Adalgisa Caccone, a researcher in the Department of Ecology & Evolutionary Biology at Yale, who is working on the project. Once these new tortoises with a high proportion of Floreana tortoise genes are five years old, her team will deliver them back to Floreana, so they can continue to trample, chew, and engineer the lush landscape. “We believe the ones that have the genomes closer to the original species will do better there,” she says. 

Project leaders are working with the local communities to maintain these changes. Karl Campbell, a project director with Re:wild, has been focusing on restoring the uninhabited islands, which he says, are now in better shape than when Darwin arrived. “The goal is to get the ecosystem to the point where it starts to repair itself,” he tells me over Zoom from Puerto Ayora. This repair starts with removing the feral chickens that eat bird eggs and harbor diseases that impact native birds and farmed chickens. They are also working with farmers to build enclosed chicken coops so the newly introduced Galápagos hawks don’t eat them. In the not-too-distant future, he hopes a visitor will experience an island teeming with its original endemic species, including the mockingbirds.

But not everyone in the Galápagos is happy with this project. The day before we went to Floreana, we took a taxi to the highlands of Santa Cruz to walk through tunnel tubes formed by lava flows and see the tortoises at El Chato tortoise reserve. At El Chato, I met Juan Tinorio, an African-Ecuadorian guide who works for the national park and whose grandparents came to Ecuador as slaves. Tinorio tells me, emphatically, that this is not just about the animals, “but also about the health and education of the people.” Most locals spend their entire lives greeting a steady stream of one higher-income, elite-college-educated tourist after another, but they themselves cannot afford the island’s only university. 

“It shouldn’t be just about conservation,” Tinorio says.

Back in Puerto Ayora, we hop on a water taxi to eat dinner at Angermeyers, one of the high-end hotels on Santa Cruz founded by one of the early German families who migrated to the islands in the 1920s. I hear the same sentiment from Enio Marteillo, a receptionist at the hotel, as I heard from Tinorio. It’s hard to find a specialist doctor, Marteillo says, and while there’s a well-equipped hospital on San Cristobal Island, it’s understaffed. 

“Without healthy ecosystems, everyone suffers.”

A 2019 University of North Carolina study of women on Isabela Island reported limited access to fresh foods and found 75 percent if the island’s inhabitants are overweight or obese. That’s a significant motivation of the Floreana project, says Campbell. And Barrigán of the Charles Darwin Foundation agrees. As an answer to some of these problems, they hope the Floreana project will increase demand for tourists, keep them coming, support the local economy, and keep the many islanders in jobs.  “It’s about the long-term health of everyone, because without healthy ecosystems, everyone suffers,” Campbell says. “If we look for easy wins, it will not produce the results we’re looking for.” 

A tourist and a crew member approach a sea lion on one of the Galápagos islands. Stefan Boness / Panos Pictures / R​edux

In search of untouched nature

The next day, we board an overnight tourist cruise run by the Ecuadorian company Klein Tours, and head eight hours north to Genovesa Island. Its remote distance to the other islands in the archipelago has stopped non-native species from invading, and it’s considered evolutionarily pristine by naturalists. That evening I watch black soaring frigatebirds following the wind baffles created by our boat. One passenger, a morose British professor of medical sociology who teaches a class on death, spots a 20-foot reef shark swimming alongside us. At dinner, I chat with Jorge Parrales, the onboard naturalist and shark biologist from Guayaquil, Ecuador. The national park trained Parrales in the early 1990s. “Before then, guides were mostly Europeans, but increasingly the park has been training residents for the jobs,” he says. Projects like the one on Floreana are expected to train more locals to become guides, improving Galápagonian’s livelihoods, he adds. 

After a rough night on the high seas, Jorge wakes us up early. “Good morning, good morning,” he says over the loudspeaker, summoning us to breakfast. We then climb onto a zodiac raft that takes us over to the island. We float past black lava cliffs where red-footed boobies nest. And then we stop and disembark to find ourselves at the foot of a steep set of stone stairs. We climb. At the top, we walk through a forest of palo santo trees, hearing only the sounds of red-footed birds and Nazca boobies all around us. These are remarkable animals made even more distinct because of how little they even notice us. They don’t flinch when you approach them, Parrales explains. 

“They have not evolved into seeing us as predators,” he says. 

In the distance, we watch a whale breaching. Humans will continue to impact these islands for better and worse, but on this beautiful morning, I finally felt a sense of the untouched nature that many Galápagos travelers want to find. The snow globe we’d shaken up in Santa Cruz was far away.

The beautiful Nazca booby. Benjamint444, GFDL 1.2
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