The Galápagos Islands: Where Evolution Made Its Case

What Darwin did observe, correctly and importantly, was the relationship between the animals of the Galápagos and similar but distinct animals on the South American mainland, and the variation within that relationship between different islands. The islands were young enough, geologically, that the isolation of each island population had not completely eliminated the evidence of the common ancestor, making the process of divergence readable in a way that longer-separated populations do not permit. The Galápagos is not where Darwin had his idea. It is where the evidence for the idea was subsequently found to have been sitting, which is a distinction that matters if you are interested in how scientific understanding actually develops rather than in the simplified narrative.

We arrived at dawn, the flight from Quito making a stop in Guayaquil before crossing to Baltra island, where the airport was built on a former US Air Force base constructed during the Second World War to protect the Panama Canal approaches. Pedro, our G Adventures guide, met us at the terminal and redirected us immediately from the boat toward a tortoise sanctuary. There was no settling in. The giant Galápagos tortoise, which can live for over 150 years and reach 250 kilograms, was wandering through the sanctuary with the unhurried confidence of an animal that has no natural predators on its home island and no particular concern about its own timeline. The oldest confirmed specimen lived to 175 years. The ones we were looking at had possibly been alive during Darwin’s visit, though I could not verify this.

The wildlife of the Galápagos differs from the wildlife of the Amazon in one specific and significant way: it has not learned to fear humans. The islands were not permanently inhabited by humans until the nineteenth century, too recently for evolutionary pressure toward human avoidance to have developed, and the conservation management of the national park since 1959 has reinforced rather than disrupted this dynamic. Sea lions sleep on the docking steps. Marine iguanas cluster on every rock surface available to them, ignoring footsteps. The blue-footed boobies perform their courtship display without interrupting it for passing snorkellers. Snorkelling with Galápagos sea lions, who treat you as a partner in an improvised game involving spiralling and sudden direction changes, produces the specific pleasure of being accepted by something wild, provisionally and on its own terms.

Our group on the San Jose covered the standard range of backgrounds that G Adventures tours tend to produce: retirees from Canada and Ireland with more time than many younger travellers, a plastics engineer from Germany, a biological sciences lecturer from Australia for whom the Galápagos was professional as well as personal, a couple who had met at a bridge club and decided at seventy to travel together. Bryan, who had worked on the development of Viagra as a pharmaceutical engineer and mentioned this with the timing of someone who has told the story before and knows exactly when to land it, was excellent company throughout. The group shared the deck of the San Jose in the evenings watching the islands recede behind us and the stars emerge in the absence of light pollution, the Milky Way visible as it is visible in very few places on earth anymore, the southern constellations in configurations that required relearning relative to the northern sky.

The Galápagos has been on UNESCO’s World Heritage endangered list at various points, the pressure of the tourism that funds its conservation also being one of the things that threatens it. The management is better now than it was twenty years ago, the visitor numbers regulated, the pathways designated, the interactions with wildlife governed by rules that the guides enforce with a seriousness that reflects genuine understanding of what is at stake. Whether the balance is right is a question the national park authority revisits constantly. The islands are small and the margin between sustainable and unsustainable visits is not wide. Pedro gave us the briefing on day one and repeated it at each landing: stay on the path, do not touch the animals, do not bring food onto the islands, take nothing away. These are not bureaucratic constraints. They are the conditions under which the thing you came to see continues to exist.