A creationist when he visited the Galápagos Islands, Darwin grasped the significance of the unique wildlife he found there only after he returned to London
Portrait of Charles Darwin J. Cameron
From the nine times I have made the 5,000-mile journey to the Galápagos Islands, to follow in Charles Darwin’s footsteps, the most enduring impression I have gained is of life’s fragility. The minute a person steps off any of the tourist trails created by the Galápagos National Park Service and heads into the untamed interior of one of these islands, there is the risk of death under the intense, equatorial sun. On Santa Cruz Island, where the Charles Darwin Research Station is located, 17 people have disappeared since 1990. Most were subsequently found alive after having become hopelessly lost in dense underbrush and rugged volcanic terrain. But some perished. One was a young Israeli tourist who lost his way in Santa Cruz’s Tortoise Reserve in 1991. Amassive, two-month search failed to find him. In fact, some of the searchers themselves became lost and had to be rescued. In the end, fishermen discovered the young man’s body. A former Israeli tank commander, he had been in top physical condition, yet had managed to go only six miles before succumbing to the searing heat and lack of fresh water. A sign in the Tortoise Reserve says bluntly: “Stop. Do not go beyond this point. You could die.”
This is the deceptively treacherous world of sun-baked lava, spiny cactus and tangled brushwood into which Charles Darwin stepped in September 1835, when he reached the Galápagos Islands with fellow crew members of the HMS Beagle. The Beagle’s captain, Robert FitzRoy, described the barren volcanic landscape as “a shore fit for Pandemonium.” At 26, Darwin had come to the archipelago, which straddles the Equator some 600 miles west of Ecuador, as part of the Beagle’s five-year mission to survey the coast of South America and to conduct a series of longitudinal measurements around the globe. Darwin’s five-week visit to these remarkable islands catalyzed the scientific revolution that now bears his name.
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Darwin’s revolutionary theory was that new species arise naturally, by a process of evolution, rather than having been created—forever immutable—by God. According to the well-established creationist theory of Darwin’s day, the exquisite adaptations of many species—such as the hinges of the bivalve shell and the wings and plumes on seeds dispersed by air—were compelling evidence that a “designer” had created each species for its intended place in the economy of nature. Darwin had wholeheartedly accepted this theory, which was bolstered by the biblical account in Genesis, until his experiences in the Galápagos Islands began to undermine this way of thinking about the biological world.
The Galápagos Islands were formed by volcanic eruptions in the recent geological past (the oldest of the islands emerged from the ocean just three million years ago), and Darwin realized that the remote setting must have presented life with a new beginning. “Seeing every height crowned with its crater, and the boundaries of most of the lava-streams still distinct, we are led to believe that within a period, geologically recent, the unbroken ocean was here spread out,” he wrote in his Journal of Researches. “Hence, both in space and time, we seem to be brought somewhat near to that great fact—that mystery of mysteries—the first appearance of new beings on this earth.”
How, Darwin asked himself, had life first come to these islands? “The natural history of these islands,” he later pointed out, “is eminently curious, and well deserves attention. Most of the organic productions are aboriginal creations, found nowhere else.” Yet all of the creatures showed a marked relationship with those from the American continent. The novel Galápagos species, Darwin reasoned, must have started out as accidental colonists from Central and South America and then diverged from their ancestral stocks after arriving in the Galápagos. As he traveled from island to island, Darwin also encountered tantalizing evidence suggesting that evolution was proceeding independently on each island, producing what appeared to be new species.
Other evidence, from the South American continent, showed that species did not seem to be stable across either geographic space or the deep reaches of paleontological time. But the particularly compelling evidence from the Galápagos Islands catapulted Darwin and life science into the modern age. He subsequently added to his daring endorsement of evolution the crucial insight that species evolve by means of natural selection: variants that are better adapted to their environments are more likely to survive and reproduce. When he finally published On the Origin of Species by Means of Natural Selection in 1859, Darwin’s revolutionary theories not only recast the study of life but also turned the Galápagos Islands into hallowed scientific ground.
More than three decades ago, I became fascinated by Darwin’s life, and especially by his historic voyage around the world. When evolutionary biologist Edward O. Wilson, whose undergraduate course I was taking at Harvard, learned of my interest, he suggested that I go to the Galápagos Islands, and he helped fund a documentary about Darwin’s voyage. My first trip, in 1968, was two years before the beginning of organized tourism in the Galápagos. Just getting to the islandswas a challenge. Our expedition flew from Guayaquil, Ecuador, in a PBY, an amphibious, twin-engine patrol plane dating back to the World War II era. We sat in seats made of mesh nets. There were numerous holes in the plane’s undercarriage, through which I could see all the way to the ocean below. The impression these starkly beautiful islands made upon me was indelible (the volcano that forms the island of Fernandina put on a spectacular eruption during our visit).
Eight expeditions later, I continue to be drawn to these islands in an effort to document their extraordinary impact on Darwin, as well as to study ecological changes since Darwin’s day. With the advent of organized tourism, much has changed. Now, two to four passenger planes fly each day to the Galápagos, bringing a total of about 100,000 tourists a year. Puerto Ayora, home to the Charles Darwin Research Station, is a booming tourist stop with a population of about 15,000 people, almost ten times the number that resided there during my first visit. As tourists enjoy their organized cruises around the islands, they are confined to 60 localities, carefully selected by the National Park Service, and are required to stay on clearly marked paths that keep them out of harm’s way.
Two main questions confront the student of Darwin’s historic visit: Where did Darwin go, and exactly how did his visit affect his scientific thinking? Answering the first turns out to be easier than one might think, thanks to a rich repository of documentary sources. The British Navy had a penchant for keeping detailed records, and the Beagle’s voyage is described in three ship’s logs, Captain FitzRoy’s personal narrative, a series of excellent maps made by the Beagle’s officers, and various watercolors and sketches by crew members. We are also able to draw on Darwin’s own extensive record of his dozen or so field trips, which encompasses more than 100 pages of unpublished notes and more than 80 pages of published material.
For five years the Beagle’s logs recorded, often on an hourly basis, where the ship was and what it was doing. Two days after the first sighting of land in the Galápagos, on September 15, 1835, the Beagle anchored in Stephens Bay on Chatham Island, now known as San Cristóbal. (All the islands were given Spanish as well as English names by their early visitors, who included Spaniards seeking Inca gold and silver in Peru, and British buccaneers intent on stealing these riches from the Spanish.) From this anchorage, the Beagle officers recorded a bearing of N10ºE to Kicker Rock, an impressive 470-foot islet about four miles off the shore, and a bearing of N45ºE to Finger Hill, a 516-foot tuff crater. When drawn on a map, the place at which these two bearings cross indicates the Beagle’s point of anchorage. Using other bearings in the Beagle’s logs, together with Darwin’s remarks in his diary and scientific notes, it is possible to reconstruct virtually all of Darwin’s landing sites and inland treks during his five-week visit. These include many regions that are either in remote or potentially dangerous locations and hence off limits to tourists.
As the Beagle sailed from east to west through the archipelago, Darwin visited four of the larger islands, where he landed at nine different sites. On San Cristóbal, Darwin was particularly drawn to a heavily “Craterized district” on the rugged, northeastern coast. “The entire surface of this part of the island,” Darwin reported, “seems to have been permeated, like a sieve, by the subterranean vapours: here and there the lava, whilst soft, has been blown into great bubbles; and on other parts, the tops of caverns similarly formed have fallen in, leaving circular pits with steep sides. From the regular form of the many craters, they gave to the country an artificial appearance, which vividly reminded me of those parts of Staffordshire, where the great iron-foundries are most numerous.”
As Darwin explored San Cristóbal, he encountered many birds and animals new to him. He marveled at the remarkable tameness of the birds, pushing a curious hawk off a branch with the barrel of his gun, and trying to catch small birds with his hands or in his cap. He also noted the striking dominance of reptiles within these islands, which made the archipelago seem like a journey back in time. On the shoreline were swarms of “hideous-looking” marine iguanas—the world’s only oceangoing lizards. On land, the Beagle crew encountered large land iguanas, closely allied to their marine cousin; a couple of smaller lizards; a snake; and giant land tortoises, after which the islands are named. (The old Spanish word galápago means saddle, which the shape of the tortoise’s carapace resembles.)
In the midst of a partly vegetated lava field on San Cristóbal, Darwin came upon two enormous tortoises, each weighing more than 200 pounds. One, he noted, “was eating a piece of cactus, and as I approached it, it stared at me and slowly stalked away; the other gave a deep hiss, and drew in its head. These huge reptiles, surrounded by the black lava, the leafless shrubs, and large cacti, seemed to my fancy like some antediluvian animals.” Altogether these giant reptiles contributed dramatically, Darwin thought, to the “strange Cyclopean scene.”
Floreana was the next of the four islands Darwin visited. The first settlement in the Galápagos had been established there just three years before, populated by convicts from Ecuador; it collapsed a few years later, after some malcontented prisoners took up arms against the local governor. On Floreana, Darwin remarked in his private diary, “I industriously collected all the animals, plants, insects, & reptiles from this Island”—adding, “It will be very interesting to find from future comparison to what district or ‘centre of creation’ the organized beings of this archipelago must be attached.” Still thinking like a creationist, Darwin was seeking to understand the islands’ strange inhabitants within the ruling biological paradigm.
After a brief stop at Tagus Cove, on Isabela, the Beagle headed for Santiago. Darwin, three crew members and his servant, Syms Covington, were left for nine days to collect specimens while the Beagle returned to San Cristóbal to obtain fresh water. Guided by a settler from Floreana who had been sent to hunt tortoises, Darwin ascended to the highlands twice to collect specimens in the humid zone. There he was able to study, in considerable detail, the habits of the tortoise.These lumbering behemoths, he found, came from all over the island to drink water at several small springs near the summit. Hordes of the giants could be seen coming and going, with necks outstretched, burying their heads in the water, “quite regardless of any spectator,” to relieve their thirst. Darwin counted the number of times that the tortoises swallowed in a minute (about ten), determined their average speed (six yards a minute), and studied their diet and mating habits. While in the highlands Darwin and his companions dined exclusively on tortoise meat. He commented that it was very tasty when roasted in the shell or made into soup.
When he was not collecting specimens, Darwin devoted time to trying to understand the islands’ geological features, especially the prominent tuff cones near his campsite at Buccaneer Cove. He was the first geologist to appreciate that such sandstone-like structures, which rise to a height of more than 1,000 feet, owe their peculiar features to submarine eruptions of lava and mud; they mix at high temperatures with seawater, producing tiny particles that shoot into the air and rain down on the land to form huge cinder cones.
On October 17, Darwin and his four Santiago companions reboarded the Beagle with their week’s haul of specimens. The ship spent the next two days completing a survey of the two northernmost islands and then, 36 days after arriving in the archipelago (during which he spent 19 days on land), the Beagle sailed for Tahiti. Although Darwin did not yet fully appreciate it, a revolution in science had begun.
Following in Darwin’s path, one understands hardships that he overcame that are not readily apparent to readers of his publications. Trekking in the Galápagos, everything is dictated by how much water one can carry, which limits each excursion to about three days—or, for longer excursions, requires stashing food and water along a route.
To Darwin, such logistics would have been even more problematic, as he did not have the lightweight equipment, such as aluminum-frame backpacks and plastic water containers, that we have today. Assisted by his servant, Darwin would have brought his geological hammer, a clinometer for measuring inclines, a shotgun for collecting birds, a compass, plant presses, rodent traps, specimen bottles, spirits of wine for preserving invertebrates, a notebook, a sleeping bag, food and, of course, water. With a characteristic understatement (reflecting perhaps his excellent physical conditioning after extensive fieldwork in South America during the previous four years), Darwin wrote of the 3,000-foot climb to the summit of Santiago merely that the walk was “a long one.” During our own climb along this route in 2004, when we were all packing about 70 pounds, one of my expedition companions was so overcome with heat exhaustion that he had to return to our base camp in Buccaneer Cove; another sprained his ankle on the treacherous footing but managed to keep going.
During a previous expedition, I and five companions came to appreciate, much more vividly than we would have liked, Darwin’s comparison of Galápagos lava flows to an imagined scene from the “Infernal regions.” We were on Santiago, where Darwin had camped for nine days, on our way to a region where tortoises could sometimes be found. Our two guides had suggested a shortcut across a coastal lava flow. What none of us could see from the vantage point of our boat’s landing site was that our route involved more than eight miles of almost continuous lava rock—not just the mile or two that our guides had led us to expect. As we began our trek across this perilous field of jagged lava, we had no idea how close to death we would all come. What was supposed to be a 6-hour excursion became a 51-hour nightmare as we climbed over jumbled piles of blocks with razor-sharp edges, and in and out of steep ravines formed by meandering lavas and collapsed lava domes. Such flows, commented Darwin, who ventured onto several smaller ones, were like “a sea petrified in its most boisterous moments.” He added, “Nothing can be imagined more rough or horrid.”