The most dramatic moment of our trip to the Galápagos Islands in May 2008 was on the last day. My wife and I were leaning over the railing on the deck of the tourist boat Integrity, watching an orca whale. The orca swam close to the boat, almost directly underneath us. Then, just ahead of the orca, a large sea turtle appeared. This was not one of the giant tortoises for which the islands are famous, but an equally massive marine turtle. The females of the species come to the islands to lay their eggs under the sand on the beaches.
My wife had met this turtle earlier in the day, when she was swimming in the ocean with a snorkel. Only a second after we saw the turtle from the boat, the orca snapped, biting through the turtle shell as if it were a pie crust. Immediately the sea turned red and fifty frigate birds appeared from nowhere to pick up the larger remaining scraps of flesh. After the frigate birds were done, flocks of smaller birds came to pick up the smaller scraps. The red sea rapidly faded. In less than a minute it was all over. It was like a scene from National Geographic on television, but real.
Perhaps we were partly responsible for the turtle’s death, since the turtle and the orca were both attracted to the boat. If we had not come to disturb the normal rhythm of her life, the turtle might now be out of harm’s way, mother to a new batch of hatchlings. But in the ordinary course of nature, without boats and tourists, such a death is not unusual. We had seen nature doing her daily work, holding the balance impartially between predator and prey. Only in our eyes is nature beautiful and cruel.
Galápagos: The Islands That Changed the World is a combination of four books in one. It is first a picture book, second a guidebook, third a history book, and fourth a political manifesto. I will describe the four components in turn and then reflect upon their message. The picture book is a gallery of magnificent photographs of the islands and their nonhuman inhabitants, taken over many years by Tui De Roy and others. Tui De Roy is a professional photographer who arrived on the islands with her family at the age of two and spent much of her life there. About fifty of the pictures are hers, including two portraits, of Darwin’s finches and of blue-footed boobies.
Darwin’s finches are inconspicuous little birds that Darwin observed when he visited the islands in 1835. They later provided crucial evidence for his theory of the origin of species. Blue-footed boobies are big seabirds that walk around the islands on bright blue duck-feet. These two images exemplify the clash of cultures that compete in historic places around the world: the culture of preservation and the culture of exploitation. Scholars and scientists try to preserve historic sites, while local entrepreneurs try to exploit them. Darwin’s finches are the chief attraction of the Galápagos for professional biologists and historians of science. Blue-footed boobies are the chief attraction for sellers of souvenirs in tourist shops.
Other photographs in the book were taken by Daniel Fitter, who was our guide on the island of Santa Cruz. All visitors to the national park must be accompanied by a licensed guide. He walked with us into the farmland to find giant tortoises, who choose to live comfortably in the small irrigated area open to human settlement rather than in the more austere environment of the national park. One of Fitter’s photographs shows the small island Daphne Major, an uninhabited volcanic crater, silhouetted against a threatening sky. Daphne Major is famous as the work-site of Peter and Rosemary Grant, who camped there for several months every year for twenty years, laboriously studying the birds and incidentally raising two daughters.
The island is small and the birds are tame enough, so that the Grants could catch and label every finch that lived there and record its individual life history, from hatching and mating to parenting and mortality. They assigned each finch to one of the thirteen endemic species by measuring the size and shape of its beak. “Endemic” means a species that breeds in the islands and nowhere else. They discovered an astonishing fact that Darwin missed: evolution by natural selection sometimes moves fast. Darwin imagined that evolution must be slower than any possible human observation, requiring thousands or millions of years to form new species. The Grants observed hybridization and segregation of species happening within a few years, fast enough to be seen and accurately measured by humans.
The reason why evolution in the Galápagos is fast is that climate and vegetation change abruptly from year to year, and natural selection is brutal. Wet and dry years unpredictably produce lush and sparse vegetation. In lush years, there are plenty of small, soft seeds, and birds with smaller beaks and quicker reproduction have an advantage. In drought years, soft seeds are scarce, and birds with larger beaks specialized to deal with unusually large, tough seeds have an advantage. Selection is fast because populations of birds with the wrong kind of beak to split seeds that happen to be abundant may be wiped out in a single season.
The life and work of the Grants is described in an excellent book, The Beak of the Finch, by Jonathan Weiner (1994), with hand-drawn illustrations by Thalia Grant and Charles Darwin.* Both of them are gifted artists. Thalia is one of the two Grant daughters who were raised on Daphne Major. Before we came to the Galápagos in 2008, we met the Grants by chance at a lunch party in Princeton. They told us that May was the best time to visit, at the transition between the wet and dry seasons. It was clearly understood that we were coming as tourists, not as scientists, and that we were not coming to Daphne Major.
The second component of Galápagos is an illustrated handbook for tourists, describing the best places and times to go walking or swimming or diving, and identifying the species of birds and reptiles and fish that the visitor will find. The handbook occupies the last fifty pages of the book. It is not intended for experts. It provides only brief descriptions of the thirteen species of Darwin’s finches, with a picture of only one of them. It describes three species of shark but only illustrates one. An expert birdwatcher or scuba diver would need a more technical and specialized handbook. This one is aimed at the average tourist who is not interested in fine distinctions between closely related species of birds and fish. For the average tourist, a visit to the Galápagos is a unique experience because of the overwhelming abundance of the populations of a few species. The number of species on the islands is not large, but a small number of them have unusually dense populations. The populations of the dominant species seem even larger than they are, because the wild creatures are unafraid and do not move away when humans walk among them.
We were lucky to arrive on the island of Española during the breeding season of the albatrosses. The handbook tells us that these birds weigh ten pounds and have a wingspan of eight feet. They live for thirty or forty years and generally mate for life. They are magnificent flyers but have difficulty with taking off and landing. Almost the entire world population of this species comes to Española to breed. We walked for miles over the island, placing our feet carefully so as not to step on the birds or their eggs. The ground was covered with majestic birds, each pair guarding a single egg, father and mother taking equal shares of the egg-sitting. In the distance over the ocean, the sky was thick with absent parents taking turns hunting for fish. The island shows what happens to a population when food is abundant and predators are lacking. These birds evolved to fly long distances over the ocean. When local fish are scarce they can find plenty of fish further away. Albatrosses, in the region of Española where we walked, seemed to cover the ground as densely as humans in Manhattan.
Another striking photograph by Tui De Roy shows a flightless cormorant spreading its wings to dry after a swim. The cormorant evolved in the opposite direction from the albatross, reducing the size of its wings until it lost the ability to fly. Cormorant and albatross coexist peacefully because they occupy separate ecological niches, the cormorant fishing close to shore and the albatross further out, the cormorant supreme as a swimmer and the albatross as a flyer. The cormorants on Española are far less abundant than the albatrosses. The population of cormorants is limited by the population of fish within diving range of the shore. We did not need to step over cormorants as we walked, since they occupy only the high rocks overlooking the ocean.
The third and fourth components of Galápagos, the history book and the political manifesto, together make up the rest of the text, written by six authors. Each author has a single chapter, except for the chief author Paul Stewart, who has four. The authors of single chapters are Patrick Morris on the geological history of the islands, Andrew Murray on the history of Darwin’s visit and his slow understanding of the creatures that he found there, Joe Stevens on the diverse ecologies of the coasts, Richard Wollocombe on the oceanic environment, and Godfrey Merlen on the successes and failures of conservation. Paul Stewart wrote a prologue chapter, a chapter on human discovery and settlement, a chapter on the flora and fauna, and a concluding chapter with the title “Galápagos—World’s End.” The authors lived and worked together on the islands, producing the BBC television series Galápagos, of which this book is a summary. Roughly speaking, the chapters by Morris, Murray, Stevens, and Wollocombe are the history book, and the chapters by Merlen and Stewart are the political manifesto.
The centerpiece of the history book is the Darwin chapter. When Darwin arrived on the Beagle, he was mainly interested in the geology of the islands rather than the biology. The islands are the tops of a group of volcanoes. They are spectacularly young, some with craters still hot from recent eruptions, others with twisted ropes of newly solidified lava stretched along the shore. After he arrived, not yet looking for biological treasures, Darwin encountered a dense concentration of black iguanas sunbathing on the shore and grazing on seaweed. He wrote in his notebook without enthusiasm:
The black Lava rocks on the beach are frequented by large (2–3 ft.) most disgusting clumsy Lizards. They are as black as the porous rocks over which they crawl.
See also Peter Grant and Rosemary Grant, How and Why Species Multiply: The Radiation of Darwin's Finches (Princeton University Press, 2007).↩
See also Peter Grant and Rosemary Grant, How and Why Species Multiply: The Radiation of Darwin’s Finches (Princeton University Press, 2007).↩