I have been walking for hours, trekking through the rainy highlands of Santa Cruz in search of a giant. I am on one of the biggest islands in the Galapagos, the archipelago known for its strange species: marine iguanas, the northern hemisphere’s only penguins – and the world’s largest tortoises. It is these lumbering giants I am looking for.
The Galapagos are home to 10 types of giant tortoises. Lacking natural predators, they regularly grow to 400 kilograms and can live for a century. But despite their size they are not as easy to find as I had anticipated.
Many regard the Galapagos as a living zoo, little changed since Charles Darwin visited here in the 1830s. The reality is starker. Climate change, invasive plants and animals – – and conflicts between humans and wildlife are among the many problems. The Galapagos National Park allows human settlements on only four islands and 97 per cent of all land here remains protected, but the human impact on the remaining 3 per cent is significant. I see it in the yapping guard dogs and the fences that protect crops and and feeding patterns.
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Two to three million years ago, tortoises arrived from South America and quickly colonised the archipelago. They were once so plentiful that they gave the islands their name – tortoise in Spanish is Galapago. Now there are , a far cry from the estimated 200,000 before the Galapagos were discovered in the 16th century. Four species went extinct because pirates and whalers prized their meat and oil.
Experience Galapagos as Darwin did in 1835: Sailing on a żěè¶ĚĘÓƵ Discovery Tour
Trudging through slick mud, combing through thick corn stalks and thicker jungle, my only encounters so far have been with farmers and their cows, goats and chickens. I head further into the bush until the misty rain restarts. Tired and wet and yet to find a tortoise, I return to the road. Thirty minutes later I am on a packed bus, hurtling along the highway that slices through jungle, descending towards the town of Puerto Ayora.
And then I finally see them. One, two, three, four – I lose count after a dozen. The giant tortoises lumber along the side of the road near town. Their remote highland habitats are now places where they face competition for food with domestic species. Life is apparently easier for them nearer to roads and towns.
Invasive Issues
Tortoises here evolved without pressure from predators, which might have been a factor in allowing them to grow so large. But that adaptation now threatens their survival. Although many now live in the lowlands around towns they must , and the presence of even a few thousand farmers in the hills means the tortoises must haul their large bodies further to find the perfect spot.
“The agricultural zone is overlapping with the migration paths of tortoises,” explains Ainoa Nieto, a wildlife veterinarian at the Charles Darwin Foundation in Puerto Ayora. She has been tracking the movements of Galapagos tortoises since 2011, and monitors their health.
“They have to cross fences, farms, and that’s when they interact with domestic animals, people, tourists,” she tells me. “The roads are creating barriers, we have some tortoises hit by cars. Farmers build fences because tortoises love eating their crops.”
But the real trouble isn’t what tortoises are dining on but who they are dining with. “It’s very typical to see cows and tortoises together in the same place eating the same things,” Nieto says. Aside from competition for food, this raises the risk tortoises will catch new pathogens.
Proximity to humans has also led to , a health threat for humans and wildlife because tortoises roam widely. Livestock given antibiotics to prevent disease defecate in the same soil and water where tortoises feed. Infections and introduced pathogens mean these isolated species face dire consequences.
Then there are the invasive species. “Ants, rats, feral dogs, donkeys, wild pigs, they love to eat tortoise eggs,” says Nieto.
Climate change also poses a problem. Higher temperatures mean more tortoises hatch as females, Nieto says, because tortoise gender is determined by egg incubation temperatures. This may threaten the viability of populations in future.
Saving Species?
With so much in flux – much of it caused by us – it’s only fitting that we’re putting it back together, or at least trying.
In 1965, the was founded to save the remaining 200-odd adult tortoises left on Pinzón Island. Since 1970, thousands of tortoises have been reared by the National Park and reintroduced to 11 islands. The open-air breeding centre is a visible sign of the support tortoises now receive. There is an uncomfortable balance, though: the centre is a tourist attraction, helping encourage more visitors to the island – which is arguably one of the main reasons why the tortoises are now in a fight for survival.
“Population is increasing in Galapagos,” Nieto admits. “I’ve seen it, I’ve lived here seven years and there’s a lot more hotels, more buildings. What do we want for the Galapagos: keep it pristine, remote, isolated and keep the species, or do we just want to receive tourists?”
On my return home I get in touch with Stephen Blake, a conservation biologist at Saint Louis University in Missouri who has spent nearly a decade studying the tortoises. “It’s a really fraught issue, what should the park do, what should Ecuador do?” he says. But he is optimistic. “If you went back 150 years on Galapagos, you would have said it was catastrophic for giant tortoises.”
People can moan about breeding centres, he says, but the bottom line is they brought one species – the Hood Island tortoise – back from the absolute brink of extinction. “And [they have] made significant contributions to keeping others going.”
