Galápagos Evolution Tour


The National Geographic Endeavour anchored off the coast of Fernandina.

At the tail end of 1831, the budding naturalist Charles Darwin boarded the Beagle for a round-the-world ocean voyage. From September 15 to October 20, 1835, the Beagle spent several weeks in the Galápagos in 1835, and Darwin himself spent about 19 days ashore. He marveled at the "imps of darkness" marine iguanas. Traveling from one island to the next, he noted the differences in tortoise shells and bird beaks. Observing, collecting and dissecting the wildlife, he had an epiphany. He had that epiphany a few years later, after he was back home, but the flamboyantly weird wildlife of the Galápagos was key; this archipelago is credited more than any other single place with inspiring the theory of natural selection, which Darwin co-founded with Alfred Russel Wallace. That theory did more than revolutionize biology. It changed how humans see our place in the universe.

In July 2014, I took the trip of a lifetime, visiting the Galápagos Islands on the National Geographic Endeavour. Like my visit to the United Kingdom the previous year, this trip was sponsored by Somerville Anderson of Glasgow, Scotland.

My souvenir park permit. Each visitor to the Galápagos needs a permit, but also needs to be accompanied by an authorized guide.

The Galápagos Archipelago consists of more than a dozen islands straddling the equator about 600 miles (1,000 kilometers) off the west coast of South America. Warm ocean water from the west, and cold ocean water from the south give the islands a surprisingly mild climate, and the animals and plants that live there include not just tropical varieties, but also animals suited to the polar regions. Penguins live in the Galápagos.

Passport stamp
The archipelago's brag-worthy passport stamp features a tortoise and a hammerhead shark.

The islands are volcanic in origin, formed by a hotspot, or mantle plume, puncturing a moving tectonic plate. In this case, the moving plate is the Nazca Plate, which creeps eastward toward South America. So the islands are younger in the west than in the east, all of them peaks on a ridge of the Nazca Plate known as the Carnegie Ridge. Although the islands may make contact with South America in the geologically distant future, they haven't been attached to a larger landmass in the past. So unlike islands such as Madagascar or Great Britain, the Galápagos never hosted life forms that ambled over from the elsewhere on a big continent and later found themselves isolated by rising seas or wrenching earthquakes. The plants and animals that colonized the Galápagos had to migrate there over a lot of open ocean.

Part of Ecuador, the islands now comprise one big national park, and visitors must obtain park passes and see the sights under the supervision of naturalist guides.

Passengers on the Endeavour expedition of July 11-20, 2014, flew in and out of Guayaquil, a coastal city of mainland Ecuador. We stepped onto the ship on July 12 and disembarked on July 19. Our plane to the islands landed on Baltra, which used to be known as South Seymour Island. Looking out the plane window, I was initially struck by the rust-colored soil — no surprise since it's oxidized iron-rich soil. Although the soil looked very different from what I'm used to at home, the vegetation, at least at a distance, reminded me of the arid shrubs of western Colorado where my family visited relatives when I was a kid.

Stumbling onto the Endeavour (July 12)

Animated dinosaurs
My home for the week: Cabin 219.

Park permits in hand, we reached the ship through a combination of short bus rides and zodiac rides. Bus rides I am familiar with. Rides on zodiacs — inflatable boats equipped with motors where the sides of the boat are also the seats — were a new experience for me. I looked for a seatbelt. Thankfully we all got life jackets. At the side of the ship, National Geographic/Lindblad crew members formed a human conveyor belt that moved our carry-on luggage and handbags up the metal staircase. We followed the bags.

At the top of the staircase, I tripped walking through the Endeavour doorway and stumbled onto the ship. Only my ego was hurt, and I consoled myself that surely nobody saw that. Then I looked up and learned that this is where the crew assembles to greet arriving guests. So I began a week of tripping, stumbling and staggering through the Galápagos. I'm clumsy. I managed to survive with nothing more than a few scrapes and bruises, and I brought plenty of meclizine.

We started out roughly in the middle of the archipelago, at Santa Cruz. The National Geographic Endeavour then headed to the western end of the Galápagos before working eastward. This is a rough approximation of our course, with red dots marking stops. Note that this map doesn't show the entire archipelago.

Approximate route for the July 12-19 cruise, based on a map provided by National Geographic/Lindblad. Red dots indicate stops.

The cruise offered plenty of luxury, but we all had to learn the routine. The expedition leader Carlos (Carlitos) Romero Franco would announce each outing and lecture over the public address system, with speakers in each room. If you didn't set your own alarm clock, Carlitos was there to wake you 15 minutes before breakfast each morning. (Lots of ladies like more than 15 minutes to look presentable, but I soon discarded much of my beauty routine, frightening as that must have been for everybody else. As Darwin observed, the Galápagos aren't really all that hot, but they are very humid compared to home. There's not much point slapping on the makeup with a putty knife when you have to wash your face several times a day. And there's no point puffing up your hairdo if you then have to smash it with a sun hat — my hat proved more effective as a wind sock. I gave up doing anything with my hair for most of the trip, so it was a sort of Judi Dench hairdo, though it made me look more like Bob Denver.) When we disembarked to hike or snorkel, we had to move locator magnets or flip switches to indicate whether we were on or off the ship, so nobody got left behind on an island. About a dozen or so passengers could ride in each zodiac, each zodiac-load accompanied by its own naturalist. Mastering the art of the wet landing proved so simple even I could do it: Swivel around on the rim of the zodiac, plant your feet in the sand, and stand up. The more complicated part of a wet landing — if what follows is a hike requiring closed shoes and socks — is getting the sand off your feet. I soon learned to use a towel to floss my toes.

The expedition offered multiple outings each day, and I usually managed at least two. I had hoped to drop a few pounds from exertion, but Lindblad feeds you well. The ship kitchen offered no shortage of healthy food. It also offered desserts with names like Chocolate Decadence, mudslide cookies, passion fruit mousse and the best sorbet I've ever tasted. Plus I got a chocolate truffle on my bed each evening. I ate all of it.

Landing at Las Bachas (July 12)

My first outing was at Las Bachas with Gaby Bohórquez. Like nearly all the naturalists on our expedition and, for that matter, our minders in Guayaquil, Gaby is from Ecuador.

Sally lightfoot crabs scuttle all over the Galápagos.
Lonesome pup
A sad-looking little sea lion pup awaits Mama's return.

Sally lightfoot crabs scuttled along the shore as we landed. I felt like I saw these crabs everywhere when I was near the shore. We could also see pelicans diving into the water looking for fish, and sea lions along the coast. Endeavour guests learned early on not to refer to sea lions as seals. They have different habitats and different appearances, at least to the trained eye. Sea lions have ear flaps. Like much of the wildlife in the Galápagos, they are unafraid of humans. A lonesome baby waiting for its mother to return from her trip to the giant grocery store in the sea is a common site on the islands, but while visitors can snap photos to our heart's content, we're to stay at least 6 feet away from the animals.

One of the first animals I noticed in the Galápagos was a dead one: an iguana decomposing along the shore of a shallow pond. Gaby said the corpses cropping up in these islands might be due to El Niño. Furthermore, she said, we likely saw fewer corpses than the conditions warranted, as storms often swept carcasses away.

Dead iguana
Evidence of El Niño? A dead iguana along the shore of a small pond at Las Bachas.

From what I could tell, the Endeavour naturalists didn't completely agree about whether an El Niño was underway in July 2014. Gaby Bohórquez discussed animal deaths possibly caused by the phenomenon, but Raul (Ruly) Menoscal expressed doubt that current conditions indicated an El Niño. He said that by far the worst El Niño conditions he saw struck in 1982-1983.

El Niño-Southern Oscillation (ENSO) is a seesawing pattern of natural variability across the tropical Pacific, driving trade winds and ocean temperatures. ENSO phases include El Niño, La Niña, and a neutral phase.

El Niño is marked by unusually warm ocean waters in the equatorial Pacific Ocean. The warm waters tend to disrupt the ocean upwelling that provides nutrients to phytoplankton. When the phytoplankton population crashes, it takes down the whole marine food chain, even though the land-based food chain fares well thanks to abundant rains. La Niña generally flips these food-chain fortunes, with marine life recovering amidst parched conditions on land.

ENSO shematic
A comparison of El Niño and La Niña conditions. Image courtesy NOAA

Scientists monitor ENSO conditions in part by observing a region known as Niño 3.4, an equatorial stretch roughly midway between South America and Oceania. NOAA's measurements of sea surface temperatures in this region from the late 19th through early 21st centuries shows that El Niño events (warm sea surface temperatures) tend to be stronger but La Niña events (cool sea surface temperatures) tend to last longer.

ENSO index
Sea surface temperatures in the tropical Pacific. Above-average temperatures are associated with El Niño, and below-average temperatures are associated with La Niña. Image courtesy NOAA.

El Niño events have both local and global consequences. Worldwide, El Niño tends to elevate temperatures, and in terms of global temperature anomalies, researchers consider the 1997-1998 event to be exceptional. But records from the Galápagos support Endeavour naturalist Ruly's argument about local impacts. In his natural history of the islands, science journalist Henry Nicholls notes that the 1982-1983 event particularly devastated local wildlife, including sea lions, fur seals (nearly all pups under three years old died), marine iguanas (almost two-thirds died), and penguins and flightless cormorants (about three-fourths died). A local fish species, the Galápagos damsel, hasn't been spotted since. It's presumed extinct.

While I visited the Galápagos in 2014, subsequent satellite and weather data showed, an El Niño was sort of starting, but it later sputtered, and really got going the following year. The El Niño starting in 2015 proved to be significant.

Visiting the Galápagos on a well-stocked, well-staffed cruise ship is one thing. Trying to settle there is another. Starting in 1929, a band of colorful, naïve Europeans tried to do that. It ended badly. Founding the ill-fated settlement were Friedrich Ritter and his sweetheart Dore Strauch. Frustrated by the economic chaos that followed World War I (and apparently bored with their spouses), they left Germany and planned to live as vegetarians in an equable climate. They settled on Floreana, which had potable water. Donning clothing only for visitors, they grew hearty vegetables.

At first, it was fine. At first, it was El Niño.

Bragging about their success in print, however, Ritter and Strauch drew other settlers. Among them was the narcissistic, self-proclaimed Baroness Eloise Wehrborn de Wagner-Bosquet, with her two contemporaneous German lovers in tow. As the baroness began to grate, the weather began to turn. La Niña had arrived. Eventually, the baroness and one of her lovers disappeared, suggesting foul play. Nearly everyone hated her so nearly everyone was a suspect. The other lover, worried he was first among equal suspects, fled Floreana and wound up dead and desiccated on Marchena Island. Meanwhile, driven nearly to starvation by failing crops, Ritter and Strauch gave up vegetarianism and ate a chicken. Strauch survived, but Ritter died of food poisoning. As NOAA scientist Michael McPhaden pointed out in 2022, Ritter might have been fine if he'd only learned how to fish. La Niña brought drought conditions on land, but abundance in the ocean.

First Glimpse of Boobies! (July 13)

Not that kind of boobies. The birds. As a high school student in the early 1980s, I read an article about the oddly colorful creatures and wanted to see some for the next 30 years. In fact, we saw blue-footed boobies flying overhead the previous day, but on North Seymour Island, I got to see some up close, including a parent booby and a fluffy (though surprisingly big) baby chick, and a male booby posing atop a pedestal waiting for his lady love.

Booby nest
Booby on a pedestal
Booby on a pedestal
Top: A blue-footed booby marks its turf with an effective method of deterring intruders. Middle: A male booby looks for love. Bottom: A booby with especially blue feet has already found a sweetheart and started a family.

In his book on the Galápagos, Wheaton College biology professor John Kricher observes that although they are less numerous than other species on the archipelago, blue-footed boobies, which actually range from Baja California to northern Peru, are the most frequently observed because they feed near the shore. Male and female boobies don't show obvious differences, but a close look at their eyes gives an indication of the sex (I didn't get that close) with females having bigger pupils. In addition, the females have slightly larger body size than the males. Although the feet remain blue round the clock, the relative lightness or darkness of the blue can vary throughout the day, Antonio said.

What evolutionary advantage could possibly come from such bright feet? One reason is that it helps the birds distinguish between species (Nazca and red-footed boobies also live in the Galápagos). Kricher says that boobies nest in mixed species colonies where, without the aid of colorful feet, boobies would make mating selections that were weird and icky. But that's not all. Boobies' bright feet likely result from sexual selection, with the male ritually moving his flappy blue feet with extra exuberance to attract a girlfriend. Kricher states that color-discerning boobies need to fall deeply enough in avian love to form a strong pair bond because both parents have to be conscientious providers if the next generation is to survive. The bluer your booby feet, the better your dates.

The blue hues may also be a reliable indicator of fitness. Nicholls describes an experiment in 2002 on an island off Mexico. Researchers switched bassinettes on booby parents, turning of them into unwitting foster parents. Booby foster dads with the brightest feet raised the heaviest, fastest-growing chicks. Reporting for The New York Times, Natalie Angier explains that blue-footed boobies have especially acute vision in the blue-green range of the color spectrum. The most-favored foot color approximates turquoise or aquamarine — a mixture of a bird's native purple-blue color, and the carotenoids derived from its fishy diet.

But even with both parents contributing, food is often scarce, and though you might enjoy watching boobies, you wouldn't necessarily want them for parents, especially if you're the baby of the brood. Kricher explains:

In the case of the blue-footed, they will raise up to three chicks if they can, but they often can't. There just is not enough food to be had. This is where asynchronous hatching enters the evolutionary equation. Boobies begin incubating when the first egg is laid, and the eggs are laid about a day apart. That means that the eggs hatch about a day or so apart, which means that the infant birds will not be the same size. The first hatched will be fed immediately, will begin to grow, and will be larger than the second. And the second will be larger than the third. In the case of the blue-footed booby, if there is not enough food, the parents just feed the largest, and the others starve. If there is a booby heaven, the expression, "Mom always liked my brother better than me" is often uttered.

Fortunately, Angier reports, suffering bullying as a baby doesn't appear to cause lasting damage in avian adulthood.

Dead iguana
An iridescent sheen, poorly captured by my camera, can be seen in the feathers of some frigatebirds.

As for sexual selection, another case was on display in the male magnificent frigatebird we saw, drumming his puffed-up red pouch hoping for a date. A female circled overhead, considering. Our guide on that outing, Antonio Adrián, pointed out that the male we saw was a tardy in finding a mate as many of his rivals already had started nests. One of the men in our group asked Antonio how many mates a male can have. One, Antonio answered. "It's all he can afford. It's all anybody can afford. We have tried in Ecuador for many years to change that, but it never changes."

Not all the frigatebirds we saw were drumming their red anatomy. We got a good look at the backs of some of as they sat in the grass. Antonio pointed out the iridescent sheen of the feathers on their backs. A purple sheen is a marker of the magnificent frigatebird species.

Along the path — and paths occur on all the islands where visitors can go — we walked past a wing that had been ripped off an unfortunate frigatebird. "Hopefully he's still doing okay," Antonio said.

Darwin gathered evidence for natural selection on the Galápagos Islands, without necessarily realizing it at the time, but he probably didn't formulate the theory until he had been back home in England for a year or two. He credited the writings of Thomas Malthus with enabling him to work out his ideas. In brief, Malthus argued that more babies are born than get to eat. We saw an example of food scarcity in this tropical not-quite-a-paradise as a mama bird tried repeatedly to feed her hungry chick. Every time she neared her baby, frigatebirds swooped trying to steal away the food. Bear in mind it would be regurgitated food they wanted to steal. Morally and gastronomically repugnant, but another example of how nature operates.

Land iguana
A tawny iguana blends into the background.

Overall I saw far fewer land iguanas than marine iguanas in the Galápagos, but I got a good look at two land iguanas on this outing. The terrestrial lizards are more flamboyantly colored than their marine cousins.

Beginner Snorkel FAIL (July 13)

Postal stamp
This postal stamp issued by the government of Ecuador hints at snorkeling delights.

Preparing for my trip, I fielded the same advice again and again: "Snorkel!" Not so easily done in my case since (a) I'd never snorkeled, (b) I'm a marginal swimmer at best, (c) I'm nearly blind without my glasses, (d) I'm too weenie to wear contacts (I endured them for six years in the 1990s, and never did get comfortable, and six years is a long time to be uncomfortable), and (e) I didn't get special prescription inserts made for a snorkel mask. A good friend gave me some daily disposable lenses, but I realized later that my eyes are worse than hers. Another friend suggested wedging the lenses from an old pair of glasses into a snorkel mask, to see if it might work. I'd look geeky, he warned, but then assured me I look geeky anyway.

Fast forward to the end of this sad tale. The thing I saw most clearly while attempting to learn to snorkel on the Rábida shore was one of my lenses, dislodged from my snorkel mask by a big wave, sinking toward the sand. At that point, I had learned just two things: (a) you should walk backwards in flippers so you don't break them, and (b) walking backwards in flippers just fills them with rocks that are exquisitely painful to the soles of your feet.

In fact, I did see something interesting. A mama sea lion was making her way into the water to feed, and her loudly protesting baby was with her, pleading with her not to go. The mama swam right in front of me, and her baby brushed past my legs behind. That was cool. But at that point, I wasn't snorkeling, just standing in thigh-deep water trying to work up the courage to put my face in the water.

I made no further attempts to snorkel. It was my loss because later in the week, snorkelers saw some awesome stuff. Not wanting to miss out on pictures, I asked for favors.

Among the first people I befriended on this trip were Bruce and Grace Gerwe, a lovely couple living in South Carolina. Grace and I commiserated about our inability to climb over rough terrain. Bruce, meanwhile, snorkeled and took great pictures.

Some of the evening lectures on the Endeavour covered how to take better photos, "the kind that could win a National Geographic photo contest." But such contests often have rules precluding entering an already-published photo. I asked the expedition leader Carlitos if, by posting something on my site, I could ruin someone's chances of winning a contest, and he sadly told me I might. So I instructed Bruce not to give me his best material. But his not-even-best material is still awfully nice.

Copyright Bruce Gerwe
Photos © 2014 by Bruce Gerwe.

Fernandina: A Sweet Young Volcanic Thing (July 14)

As the Galápagos Islands have been formed by a hotspot under a tectonic plate moving toward the east, the islands are younger in the east. Fernandina and Isabela (Albemarle in Darwin's Day) are geological infants, only about 700,000 years old. Overnight on July 13 and 14, the Endeavour hauled all of us all the way to Fernandina. On July 14, we landed at Punta Espinoza.

Fernandina is a shield volcano, meaning it's a broad, low-profile volcano that derives its name from its resemblance to an ancient warrior shield. In fact, Fernandina resembles an overturned bowl, and it remains active. As recently as 1995, an eruption produced lava flows reaching all the way to the coast. Our guide Gaby told us about an 1825 eruption observed by explorer Benjamin Morrell, who had an (un)enviable vantage point on a nearby ship. It must have been an exciting sight for the sailors, but excitement can quickly lose its charm. As lava flowed to the ocean — Punta Espinoza under our feet may have been formed by that very eruption — the ship was stuck near the volcano for lack of wind. In a matter of hours, the water temperature rose from about 60°F to 100°F, and the air temperature rose from 70°F to nearly 115°F. Tar on the ship had started to melt. A breeze finally gave the sailors their escape.

A handful of Fernandina pavement
Naturalist guide Gaby holds a sample of the material covering Fernandina, minus the poop.

Fernandina used to be on the ocean floor, a fact illustrated by the island's pavement of volcanic rocks, smashed seashells, detached sea urchin spines and, regrettably, excrement. This still-active volcano is an example of how quickly life takes hold in an inhospitable place. Little black crabs crawled over the rocks we had to climb onto in our landing (I was almost too freaked out to come ashore), and a shallow pool just onshore held tiny sea urchins. Darwin never set foot on Fernandina, but this island abounds with the animals he observed: marine iguanas.

It is a hideous-looking creature, of a dirty black colour, stupid and sluggish in its movements. . . . When in the water this lizard swims with perfect ease and quickness, by a serpentine movement of its body and flattened tail — the legs being motionless and closely collapsed on its sides. A seaman on board sank one, with a heavy weight attached to it, thinking thus to kill it directly; but when, an hour afterwards, he drew up the line, it was quite active. Their limbs and strong claws are admirably adapted for crawling over the rugged and fissured masses of lava, which everywhere form the coast. In such situations, a group of six or seven of these hideous reptiles may oftentimes be seen on the black rocks, a few feet above the surf, basking in the sun with outstretched legs.

Marine iguanas were abundant on our walk. They were hardly cuddly, but I wouldn't call them hideous. They have a prehistoric aura about them. Outfit them with some cardboard spikes, and they could play dinosaurs in a low-budget sci-fi film from the 1960s. And Darwin and I agree that they are accomplished swimmers. I saw several of them crawl into the water and swim off with the sideways slither he described.

Iguanas everywhere
A close look at a marine iguana
A serpentine swimmer
Top: Iguana pavement. Middle: A close look at a marine iguana. Bottom: A marine iguana swims off with the serpentine motion Darwin discussed.

Kricher hypothesizes that the iguanas' black color isn't for camouflage so much as heat generation, with their dark skin absorbing more of the sun's radiation. Whether or not they need camouflage, these lizards certainly have it. They blend in with the black lava so well I had to take care not to step on one of them. The iguanas were slow moving, but the diminutive lava lizards weren't. They scampered over the rocks, over the broken shells, and often over the iguanas.

Another adaptation to lava-lined shores besides swimming is the marine iguana's diet. Iguanas are herbivorous, but most of them eat terrestrial plants. Opening the stomachs of several iguanas, Darwin found seaweed. And marine iguanas show what may be an exceptional adaptation to the food-chain disruptions caused by El Niño. When El Niño strikes, bigger animals suffer the most, but marine iguanas can shrink — not just have smaller babies, but shrink. Two studies published in 2000, one study lasting eight years and the other study lasting 18, detected body shortening of as much as 20 percent. Connective tissue and cartilage account for 10 percent of body length at most, the authors said, so the shrinkage must involve bones, too.

These marine iguanas are the only truly marine lizards in the world. Since this island was never attached to a continent, and since its separated from the nearest continent by hundreds of miles, it's not unreasonable to wonder how on Earth their ancestors got here. Kricher points out that, although they don't swim nearly as impressively as this species, the common iguana (unimaginatively named Iguana iguana) might be its distant ancestor. Such animals in the lowland tropics can swim in rivers. Furthermore, during the rainy season, floating mats of vegetation in the Guayas River, which empties into the Pacific Ocean near Guayaquil, can be seen from the sky.

Thus it is far from implausible that the ancestor of all the marine and, for that matter, land iguanas on the Galapagos might have been a pregnant common iguana trapped on a floating mass of vegetation torn from the river border in equatorial South America and destined for a journey partway across an ocean.

Pahoehoe lava
Pahoehoe lava at our landing site on Fernandina.

The picture gets even more colorful. Islands in the Galápagos can not only rise above the ocean surface (essentially how they form). They can also eventually sink. Since the end of the last ice age, the islands have been even more likely to disappear below the water line as melting ice has raised ocean levels. So it's entirely possible that the ancestors of many of today's island inhabitants evolved on islands that have since sunk below the waves. Different techniques of sampling genetic material have given different estimates, but Galápagos iguana species may have diverged from Central American ancestors as much as 10 million years ago, and further bifurcated into land and marine species around 4 million to 5 million years ago. A 2015 study concluded that within-island speciation and between-island hybridization have continued ever since, and both phenomena may have enabled marine iguanas to persist despite repeated climate changes and resulting population crashes.

The lava at Punta Espinoza was made for photographs. It's a type of lava known as pahoehoe, a Hawaiian term for ropelike, which it is. This type of lava forms from fast-moving lava rivers. Gaby told us of another type of lava, given the Hawaiian name of aa ("ouch ouch") lava. But that, she said, we would encounter the next day. Indeed I would. More on that later.

A Zodiac Ride along the Coast of Isabela (July 14)

My first couple days in the Galápagos, I could say I was visiting the same archipelago as Charles Darwin, but I couldn't say I'd visited the same island until the afternoon of July 14. And it was fitting that, at the same time, I should get my first photo of a species that illustrates what he described in his "one long argument" for evolution.

When talking to ship passengers, Carlitos corrected our usage of terms. We shouldn't simply say Endeavour but National Geographic Endeavour. We shouldn't simply say penguins, but Galápagos penguins. And we shouldn't simply say cormorant, but flightless cormorant. Of nearly 40 cormorant species worldwide, just one species doesn't fly. It lives in the Galápagos, and it supplements its tiny, vestigial, ineffectual wings with big flipper feet and a big bottom (useful for diving). This bird species has replaced flight with swimming. In terms of energy, flight is expensive, and without many predators, and with its food source localized and underwater, this bird is better position if it swims instead of takes to the sky.

This was as close as I got to any of these birds. Several of them hung out together along the Isabela coast, heads bent downward as if they had just been scolded.

Cormorants along the coast.

Other birds hung out along the store, including boobies and pelicans. And our little group in the zodiac saw penguins, but they moved too speedy for me to photograph.

My Close Encounter with Aa Lava (July 15)

On July 14, I got to look at the island of Isabela. The next morning, I finally set foot on it. We visited Urbina Bay. Our National Geographic Endeavour Daily Program explained that in 1954, about a half a square mile (1.5 square kilometers) of marine reef just off the coast "uplifted almost instantaneously." The reef rose as much as 15 feet (4 meters). That's not a great distance, but it was enough to push the reef above the ocean surface.

In front of the coral
Roughing it on Isabela, standing in front of a big reef.
Corals can retain their intricate structures even after decades above water.

Groups from the ship hiked to the uplifted area where big corals sat, still largely intact if dried out, on the uplifted land. The recently displaced reefs are still recognizable as coral and quite photogenic, even if I'm not.

En route to the corals, we passed giant tortoise shells no longer needed by their dead owners, and the skull of a goat. Raul, who goes by Ruly, was our guide on this outing, and he gave a mini-lecture on introduced species. The Galápagos archipelago doesn't hold any cities as big as, for instance Guayaquil, but the islands are inhabited, and have been since before Darwin's time. When humans relocate, we generally bring stuff with us, intentionally (goats) or not (rats). Goats proved ruinous to the Galápagos habitats, munching so much vegetation they caused erosion, and eating up the food supply of giant tortoises. The Galápagos has made terrific strides in goat eradication, but at great expense, and threats to intentionally introduce or reintroduce goats are common. Ruly passed the goat skull around the group in case anybody wanted a closer look. When a little girl dutifully offered the skull to one woman in our group, she calmly replied, "I'm good," and the skull got passed to somebody else instead.

Land iguana
A land iguana at the Charles Darwin Research Station.

We also passed some land iguanas on the path, and Ruly said that he had noticed the iguanas seemed more stressed by the presence of humans — evidenced by their faster retreats — than they used to be. As he did about other inhabitants of the archipelago, Darwin marveled at the tameness of land iguanas during his visit, recounting in Voyage of the Beagle:

They inhabit burrows, which they sometimes make between fragments of lava, but more generally on level patches of the soft sandstone-like tuff. The holes do not appear to be very deep, and they enter the ground at a small angle; so that when walking over these lizard-warrens, the soil is constantly giving way, much to the annoyance of the tired walker. This animal, when making its burrow, works alternately the opposite sides of its body. One front leg for a short time scratches up the soil, and throws it towards the hind foot, which is well placed so as to heave it beyond the mouth of the hole. That side of the body being tired, the other takes up the task, and so on alternately. I watched one for a long time, till half its body was buried; I then walked up and pulled it by the tail, at this it was greatly astonished, and soon shuffled up to see what was the matter; and then stared me in the face, as much as to say, "What made you pull my tail?"

The hike we took was a big loop, so not all groups from the Endeavour walked the loop in the same direction. Carlitos warned that part of the hike would be over difficult terrain, and I was a bit apprehensive. Early in the hike, I relaxed a bit since the terrain didn't seem so bad. Turns out, we took the loop with the biggest, most jagged rocks at the end of the hike. And this lava wasn't the pretty, picturesque pahoehoe lava that we'd seen on Fernandina. This was aa lava, and having spent the morning hiking in humid conditions, I was even clumsier than usual. Miscalculating a step, I learned for myself why this lava is named "ouch ouch." Fortunately no more than a scrape, but it felt good to get back to the ship.

Copyright Ann Dibble
Photo © 2014 by Ann Dibble.

Hikers who avoided the aa lava had a great time. One of my buddies from the cruise, Ann Dibble, participated in the hike tailored to photography buffs, and snapped a photo of a pelican who'd just caught his breakfast.

Tagus Cove, Darwin's Disappointment and Pretty Pink Lizards (July 15)

After my unintentional snuggle with aa lava that morning, I was a little uneasy about the hike planned for the late afternoon, especially since our Daily Program promised "an INVIGORATING FAST hike" up the side of a volcanic cone. But this was a place where Darwin himself had landed for a better look at the volcanic terrain, and I didn't want to retreat after one challenging hike. In the end, I was glad I went.

When the Beagle visited, Isabela Island was known as Albemarle, and Tagus Cove was known as Blonde Cove. These days, the lake in the volcanic crater that you can see along the tourist hiking path is named Darwin Lake, and rock outcrops in Tagus Cove are littered with giant graffiti left there generations ago. Tagus Cove is actually the remains of a giant volcanic cone that has lost its southern rim to erosion.

Gaby near Darwin Lake
Gaby discusses the water and the terrain at Tagus Cove.

We had a dry landing, so no frantic toe flossing along the shore, and this path, though steep in parts, wasn't lined with aa lava. There were even a couple wooden staircases on the path, admittedly missing some steps here and there. Our hike was at sunset and an evening breeze kept us cool.

Darwin Lake is maybe two-thirds of the way up the path. Ironically the lake now named for the naturalist disappointed him when he visited. Although it's above sea level, its water is even saltier than ocean water, something the young naturalist wasn't happy to learn.

At the top of the path is an overlook where you can see some of the volcanoes that fascinated Darwin, including Wolf Volcano. Wolf Volcano caught my attention several years before I visited the Galápagos. In 2009, an international team of researchers discussed a previously overlooked land iguana species in the Galápagos. It's a shame this species was overlooked for so long because it's a pretty shade of pink. The authors of the 2009 study called the species rosada and explained that the species may have evolved about 5.7 million years ago — another example of current species whose ancestors likely lived on Galápagos islands that have since sunk below the ocean surface. When I mentioned the iguanas to Gaby, she told me that that clouds often hide the summit of Wolf Volcano, as they did the day of our hike, but the volcano's summit is frequently above the cloud layer, and it's dry there. Hiking to the summit of Wolf is beyond my creampuff capacity, so I didn't get to see any pink iguanas for myself. Poo.

Wolf Volcano
Left: Wolf Volcano from the ground. Right: Wolf Volcano from the sky. Image courtesy NASA.

Survival of the Fittest (and the Lucky) in Buccaneer Cove (July 16)

Passengers on the Endeavour spent July 16 on or around Santiago (called James in the 19th century). That morning, I made my first (and probably last) attempt to kayak there, in Buccaneer Cove. Although crew members of the Beagle called the island by a different name, the current name of Buccaneer Cove was surely in use then; pirates skulked about the Galápagos long before the respectable expedition ship anchored there.

So I was encouraged in my kayaking effort by one of the friends I made on the trip: Eva Ravenel of South Carolina. Eva promised me I'd like it. Like Tagus Cove the previous day, this was a place Darwin had been. In fact, this is where he landed for his longest stretch on land in the Galápagos: nine days. I wasn't there for nine days, but before my kayaking stint was finished, I felt like I'd been there that long.

We kayakers rode zodiacs from the Endeavour to where a string of bright yellow kayaks were waiting. Getting out of a zodiac and into a kayak is a bit trickier than making a wet landing, but not terribly difficult. The hard part came right afterwards. Having never kayaked before, I sat in the front. Sitting in the back was Kevin Nicolai, a high school student and certified diver and the main reason I'm still alive to type this.

If I understand anything about kayaking, you alternate paddling on the right and left sides to go strait, and all on one side to turn. Something I learned from Kevin is that if you really need to turn, you can paddle backwards. But I'm pretty sure you're not supposed to hit the side of the kayak with the handle as you try to paddle. I suspect it's bad form. If nothing else, the sound is annoying. For pity's sake, it annoyed me, and I was the one doing it. But I couldn't manage to raise the paddle high enough to avoid doing it. I blame my short torso.

Kevin Nicolai
Kevin Nicolai: fit and pulling more than his weight.
Buccaneer Cove
Wind whipped the waters of Buccaneer Cove the day we kayaked. It really did.

Kevin saw to the rudder (I didn't know kayaks even had such things) and instructed me on what to do. But we paddled and paddled, and much of the time, it felt like we were getting nowhere. In fact, we were, but I felt like we were moving at the pace of a land iguana. I began to complain noisily about how much Lindblad had fed me. The more ineffectual my arms felt, the bigger my butt felt. (It also felt wet, but I was reassured to learn that was just sea water in the bottom of the boat. If someone heard, without context, how many times I had to change into dry pants on this trip, that person might suspect I have issues.) I began to imagine what I was going to do to Eva if I ever saw her again. Kevin assured me that the return trip would be easier, but my middle-aged spinster arms were getting tired and sore. I might as well have been out there with cormorant wings. I wasn't sure I could paddle back the distance we had come. If I hadn't had a big, strapping, good-natured kayaker with me, I think I'd be at the bottom of Buccaneer Cove. Fortunately the zodiac picked us up before we had to paddle back to where we had started. With the help of the driver, our guide, Ximena Córdova, pulled a gaggle of tired, limp kayakers into the zodiac. Once we were inside, Ximena told us that we'd kayaked in very difficult conditions, thanks to the wind. She was glad "there were no incidents." Kevin generously told me I had pulled my own weight, but I'm not so sure. I'd eaten Chocolate Decadence and my bedtime truffle the night before.

I didn't exactly have the very best time of my life kayaking, but I very much enjoyed finding I could do it and not die. Our next outing was much easier: a glass bottom boat ride. As we lined up to disembark for the easier outing, Kevin was there with his family. When I told him I was going too, I got a fist bump! I think that means I'm cool.

Yellow Jackets and Fur Seals (July 16)

Our afternoon outing on Santiago included a hike along the shore near Puerto Egas. It was another wet landing followed by a fit of toe flossing, but the hike itself wasn't difficult. The most difficulty I experienced was from my openwork shoes that sucked in every annoying little rock in a 5-foot radius. And the wasps. I hate wasps.

"Ignore the wasps, even if they land on your nose," Ximena advised. The wretched little creatures were already buzzing around my eyes, preparing to land on my nose. I didn't ignore them; I went fishing for my DEET wipes.

Luckily they didn't hang around for much of our hike, which featured more marine iguanas crawling over deeply weathered rocks. Ximena credited the ocean water with all the convoluted rock layers and tide pools we saw.

Puerto Egas
Marine lizards and a fur seal at Puerto Egas.

We had seen sea lions throughout the week, but Puerto Egas offered us a close glimpse of fur seals. The snorkelers in particular found sea lions to be curious and playful, but fur seals are more reticent. Still, we encountered a big group of fur seals having what appeared to be a very good time in the tide pools.

Spats, Studs and the Hottest House in Ecuador (July 17)

Darwin didn't make it to Santa Cruz, but that island is now home to a research station bearing his name. Located in the coastal town of Puerto Ayora and operated by the Charles Darwin Foundation, the research station focuses much of its energy on biodiversity and conservation, including a captive breeding program for giant tortoises. The research station has for decades enjoyed international support but our guide Antonio started the tour by discussing how such support can misfire when the people trying to help don't understand the situation they're trying to improve.

Station building
One of the buildings at the Charles Darwin Research Station.
Snow-proof house in Ecuador
The hottest house in Ecuador? A gift from the Swiss intended to withstand tropical snow.

Decades before our visit, scientists in the Galápagos, asked what they could really use, replied that they needed buildings such as housing quarters at the station. The Swiss came to the rescue and built a lovely A-frame house perfect for the Swiss Alps in winter. Its steep-sided roof would keep from collapsing under the weight of heavy snow, and it faced east-west, so it could benefit from as much sunlight as possible. It still stands at the station today and it is, according to Antonio, the hottest house in Ecuador. "When Swiss scientists come to the station, we make them stay there," he said.

The main attractions at the station are the giant tortoises. These big lumbering reptiles were doing fine until humans showed up. Not afraid of people, and not fast enough to get away even if they had been afraid, many tortoises quickly transmuted into soup. Even Darwin pronounced it tasty. Because tortoises don't need to eat often, they could survive on a ship for months as low-maintenance meat not in need of refrigeration.

Fighting tortoises
Content dome-shelled tortoise
Top: Would-be solitary tortoises fight in close quarters at the research station. Bottom: A dome-shelled tortoise enjoys the space at the farm.

Besides drinking tortoise soup, tasting tortoise meat, and riding on the back of a tortoise, however, Darwin had other interests. Gordon Chancellor and Randal Keynes explain at Darwin Online:

In a conversation about the giant Galápagos tortoises of which there were small numbers on the island, [English Vice-Governor, Nicholas] Lawson said that the tortoises on different islands showed "slight variations in the form of the shell." He claimed that he could, "on seeing a tortoise, pronounce with certainty from which island it has been brought." It is not clear whether Darwin attached any significance to the remark at the time, but he was to remember it later.

Tortoise family tree
Proposed family tree of Galápagos tortoises. From "Origin and Evolutionary Relationships of Giant Galápagos Tortoises" by Caccone, Gibbs, Ketmaier, Suatoni and Powell.

Lawson might have overstated his skill a bit, but multiple varieties of tortoise have lived on the Galápagos. The origins of these animals is murky. In 1999, a team of geneticists published their research on the mitochondrial DNA of tortoises living in the Galápagos (Geochelone nigra). They made the surprising finding that the closest mainland relative was not one of the big tortoises from South America but instead the fairly small-bodied Chaco tortoise. They also found that tortoises on the island of Isabela probably descended from more than one colonization. A 2024 study, however, reached a very different conclusion. After analyzing Late Pleistocene fossils from Ecuador, paleontologists concluded that big tortoises lived on the mainland, and it may have been supersized specimens that floated to the Galápagos, even if modern South American tortoises today are smaller.

Like the iguanas, tortoises have likely evolved longer than the present islands have existed, so the ancestors must have lived on islands that are now under the waves.

Without access to mitochondrial DNA sequences, tourists would probably struggle to identify all the varieties, but at opposite ends of the tortoise continuum are two types clearly different from each other: those with dome-shaped shells, and those with saddle-shaped shells. Both types live on the grounds of the Charles Darwin Research Station.

Dome-shelled and saddle-shelled tortoises occupy different habitats. Common in the highlands, where conditions are generally wetter than at sea level, dome-shelled tortoises feed on abundant ground vegetation. In contrast, saddle-shelled tortoises feed on cacti, and have to raise their heads to reach the good stuff. The notches over their necks, along with their relatively long legs, enable this feeding behavior. It appears that, just as the cacti have exerted selection pressures on the tortoises, the reptiles have shaped the plants. Islands that have never hosted tortoises have low-to-the-ground cacti. In contrast, on the once-tortoise-rich island of Santa Fé, one cactus species can grow up to 40 feet tall.

Saddleback stud Diego ponders his achievements.

The research station's efforts to bring saddleback tortoises back from the bring was long marked by failure, typified by the tortoise known as Lonesome George. George died in 2012, but his successor, Diego, has been a dazzling success. Diego relocated to the Charles Darwin Research Station from the San Diego Zoo. Antonio told us that Diego has sired more than 2,000 babies. I asked for clarification, assuming Antonio meant descendants, but he said no. He meant direct children. Resting inside his pen, Diego looked tired but pleased with himself.

Copyright Ann Dibble
Photo © 2014 by Ann Dibble.

Plenty of dome-shelled tortoises at the station have to share quarters — an arrangement they don't much like. They are solitary animals who tolerate each other just long enough to place an order for the next generation. As we looked over one batch of big reptiles, Antonio told us they were fighting. It didn't look like they were doing anything, but he assured us they were fighting, just at tortoise speed. They stare at each other and if they both keep staring, one of them moves to bite the other. Not long afterwards, we did witness some attempted bites.

Antonio also delivered a mini-lecture on the station's attempts to reestablish native plants that have declined in recent decades. He said that plants that could cost botanical gardens in distant cities thousands of dollars to acquire are sometimes given to Galápagos residents free of charge to encourage local cultivation.

Shopping bag
Mission accomplished: Galápagos Jewelry shopping bag.

After our guided tours at the Charles Darwin Research Station concluded, we were released from supervision — for about 45 minutes. We were to meet up with the rest of the group at a restaurant called The Rock, down Puerto Ayora's main street. We were encouraged to visit the fish market along the shore. Ann Dibble snapped a spectacular photo of a sea lion "bellying up to the bar" for scraps. But I missed the whole spectacle. I'd waited all week for this opportunity, something I could finally do as well as any snorkeler or kayaker: shopping.

I expected my first stop to be the research station's own gift shop, but I was sorely disappointed to find it closed (a development that could have dire consequences for the research station). After mourning my losses, I trotted down the main street in search of bling. In fact, I'd been looking for that all week, and found some of it in the Endeavour's own gift shop. I especially fell for the booby-blue-feet earrings and a matching t-shirt.

Highland tree
Vines hang from a highland tree not far from the tortoise farm.

After our rendezvous at The Rock, we boarded buses bound for the highlands of Santa Cruz. The habitats we had seen up to that point were arid. To me, some parts of the Galápagos looked remotely like the high desert of western Colorado, but only remotely, and the islands seemed completely foreign to many Endeavour passengers. The landscape in the highlands seemed a little more familiar, with tall, leafy trees and some ornamental (though invasive) plants. But the highlands were rainy. This was not surprising as (a) our Daily Program warned us about possible rain, and (b) this was the one day I didn't bring along my rain slicker. Fortunately I brought along a compact "emergency rain poncho" given to me by one of my brothers years ago. It looked like a clear Hefty bag with a hood, but it kept me dry.

The main attraction in the highlands was the Manzanillo Ranch where dome-shelled tortoises are bred in their natural habitat. We were all provided with wellingtons so we wouldn't have to negotiate the terrain in our own shoes. A good thing, because I've never seen so much mud in my life. But there the tortoises were. The spacious grounds apparently agreed with them; I didn't see any of them fighting.

Seeing Red at Punta Pitt (July 18)

The last island our cruise visited was the first one Darwin saw: San Cristóbal (Chatham in his day). "Nothing could be less inviting than the first appearance," he wrote of the island. His uncharitable assessment might have been driven at least partly by the rocks.

Sesuvium far
Sesuvium near
Top: Sesuvium from a distance. Bottom: Sesuvium close-up.
Red-footed booby
A red-footed booby preens near the path.

As mentioned earlier, the Galápagos Islands are younger in the west and older in the east. Located at the western end of the archipelago, Fernandina is a 700,000-year-old shield volcano. At the eastern end of the archipelago is San Cristobal. It's still quite young, geologically speaking, but it's a 2.4-million-year-old volcano badly crunched by tectonic forces. The rocks of San Cristóbal present a tortured appearance around Punta Pitt, and they don't sport much vegetation to cover their convoluted layers. But one type of vegetation that does thrive there is like nothing I've seen anywhere else: brilliant red Sesuvium. Looking closely at the plants, I realized that the crimson color comes not from flowers but from the stems and leaves.

I glimpsed something else rich in red, namely a red-footed booby. This individual was preening among the jagged rocks, and we all snapped photos of the lonesome-looking bird.

Reaching the land of red-footed boobies and red Sesuvium took some effort. Getting there entailed not just hiking but some real climbing, and I am not a climber. (Still, it was better than the aa lava of Urbina Bay.) The worst part about climbing up is that you'll have to climb back down. I survived without a mishap, but I particularly remember one spot, a nearly vertical stretch of rock that looked like it was about three-fourths of my own height. Returning to it on my way back to the coast, I momentarily wondered how I had climbed up, but immediately moved on to wondering how I was going to climb down it. There was nothing to hold onto. I considered jumping and immediately thought of a cousin who, after locking herself out of her house, tried jumping over her back fence to the unlocked back door and broke both her ankles. (My memory likes to torture me sometimes.) Then I remembered a trick for poor climbers: Before you land on your butt, just sit on it and shimmy downwards. It worked, and once I dislodged the wedgie, I was fine.

Jagged rocks of San Cristobal Island
Jagged rocks of San Cristobal Island
Top: San Cristóbal's forbidding rocks. Bottom: Looking down on the beach from the top of the trail.

Back at the coast, I took a last close look at sea lions on the beach before climbing onto the zodiac and back to the ship. Snorkelers would take one final dip later that afternoon, but the climb was my last outing in the Galápagos.

León Dormido and the Long Goodbye (July 18)

Toward the end of our trip, as Carlitos gave us our final logistical briefing, we realized what a quick turnaround the Endeavour experiences every week. The same airplane that brings a new shipload of passengers also flies out the big batch of passengers who must depart. On the morning of July 19, our naturalists accompanied us on our final set of zodiac rides to the airport then picked up the lucky new passengers who would succeed us in snorkeling, kayaking, hiking and feasting.

Leon Dormido
From a distance, León Dormido looks like a pair of tiny rocks in the middle of a vast ocean.

As the sun set on July 18, the National Geographic Endeavour circumnavigated León Dormido ("Sleeping Lion" also known as Kicker Rock), a mismatched pair of rocky spires off the coast of San Cristóbal. Darwin reckoned these rocks had once been at the center of a long-gone volcano. A couple hours earlier, while the snorkelers ogled sharks on their final outing, I photographed León Dormido, which looked tiny at that distance. During our final evening on the ship, we snapped photos of each other, with León Dormido and the sunset as backdrops.

Going to the Galápagos by myself, I had been apprehensive about being a lone traveler among people with friends and family members, but I met wonderful people among the crew and fellow tourists in my week at sea. We traveled back home to the states as a big band of buddies.

I was lucky to visit the Galápagos on a cruise populated by great people, including an Ecuadorian crew of some of the hardest-working people I've ever met. Ecuador has less than 100,000 square miles of land area, yet manages nearly 500,000 square miles of ocean. By the start of 2024, a decade after my visit, Ecuador's task looked increasingly difficult.

The Archipelago's Effect on Darwin

Many school children still learn an incorrect version of history, namely that Charles Darwin hit upon his theory of natural selection while in the Galápagos, but his own notes indicate that he didn't work out his theory until he'd been home in England for a bit. In fact, his collecting was a bit sloppy and he mixed together his finch specimens so badly that he needed the help of ornithologist John Gould to sort them out. Darwin took more careful notice of the mockingbird species and though he brought home only four specimens, he studied the birds collected by FitzRoy and others.

To evaluate the plant specimens he brought home, he turned to the talented young botanist Joseph Hooker who happily concluded that Darwin had returned home with more than 200 plant species, and more than half of them were new to science. Darwin went on to study the potential of plants to cross ocean waters in the late 1850s, leaving seeds in seawater to see which ones could survive and germinate. Plenty of seeds managed to survive the salt and also float, and Nicholls writes, "a back-of-the-envelope calculation suggests that a buoyant seed could reach the archipelago in just over a week." The majority of flowering plants native to the Galápagos exhibit yet another useful trait for colonization: the ability to self-pollinate.

Darwin also turned to Richard Owen to help identify the fossils the young explorer had collected from South America. That situation proved ironic in that Owen helped Darwin find more evidence for evolution despite Owen being an ardent opponent of "transmutation."

Beak varieties from the Galápagos. From Evolution: The Triumph of an Idea by Carl Zimmer.

Darwin found tantalizing hints of evolution on the Galápagos but he based his theory of natural selection on mountains of evidence outside of the island chain, too. If he had been the only scientist to study the Galápagos, the archipelago probably would not be so closely linked with evolution, but since his time, research has continued. In Evolution: The Triumph of an Idea, Carl Zimmer describes more recent research:

Sometimes nature runs evolutionary experiments of its own, without any help from humans whatsoever. In these cases, biologist simply have to observe. After Darwin left the Galápagos, scientists came back every few decades to study his puzzling finches. In 1973 Peter and Rosemary Grant, husband and wife biologists now at Princeton University, arrived on the islands to study the effects of natural selection on the birds. . . . In 1977 the wet season never came. On Daphne Island [Daphne Major], where the Grants worked, the drought was lethal. . . . The survivors of the drought mated in 1978, and the Grants could see evolution's mark on their offspring. A new generation of Geospiza fortis was born, and the Grants' student Peter Boag discovered that on average their beaks were 4 percent larger than those of the previous generation. The big-beaked finches, which had fared better during the drought, had passed their trait to the offspring and altered the profile of the entire population. . . . In 1983 a season of heavy rains and abundant seeds favored finches with smaller beaks, and the Grants found that by 1985 their average size had dropped 2.5 percent. Short-term climate fluctuations can make natural selection drive a population of animals in circles. But under other conditions, it can push them in one direction for a long time.

In 2015, the Grants contributed to a genetic study of Darwin's finches. The study concluded that hybridization has led to mixed-ancestry species in the Galápagos Islands and on Cocos Island, and that a gene named ALX1 — a gene that also plays a role in shaping human faces — contributed to beak diversification. Peter Grant remarked that Darwin might need a "crash course in genetics" to fully grasp the new study but would be pleased to find the new findings fit perfectly with what he proposed more than 150 years earlier.

Changes in beak size haven't been the only examples of population change the Grants observed on Daphne Major. In 1981, a big-headed, stout-bodied, cute-as-a-Muppet finch nicknamed Big Bird settled on the island. He had an unusual song, and a beak capable of partaking of big and little seeds, along with cactus nectar and pollen. Science reporter Jonathan Weiner writes:

Big Bird mated with a medium-beak on Daphne. Their offspring sang the new song of Big Bird. And slowly, Big Bird became a patriarch. He lived 13 years, a long time for one of Darwin's finches. His children, grandchildren and great-grandchildren all sang his song, and they were clannish. They roosted in hearing distance of one another on the slopes of Daphne Major. What's more, they bred only among their kind, generation after generation.

That Big Bird spawned a new species, the Grants concluded, was "highly unlikely but not impossible." If he really had, however, the Grants fancied the name Geospiza strenuirostris, meaning "strong, vigorous and active."

The Galápagos continue to serve as a real-life laboratory in natural selection, but fossil-fuel burning may change conditions faster than species can adapt. Since the unusually destructive El Niño of 1982-1983, the world's oceans have warmed by at least 0.5°C. Launching from a warmer starting point than in the early 1980s, El Niño events will likely become more frequent and intense. Corals in the region are already beginning to bleach — a telltale sign of warming waters. Meanwhile, as ocean waters absorb more carbon dioxide, resulting ocean acidification will harm corals and mollusks. On land, warming conditions might hamper the formation of garúa — the fog that waters highland plants. Climate change aside, introduced plant species are spreading like, well, weeds.

As for the 19th-century naturalist, when he established a set of private notes on the subject of evolution, or transmutation as it was sometimes called, he soon acknowledged the importance of the islands:

In July [1837] opened first note Book on "transmutation of Species". — Had been greatly struck from about month of previous March on character of S. American fossils — & species on Galapagos Archipelago. — These facts origin (especially latter) of all my views.

By 1845, he had refined his ideas:

Somerville Anderson
Somerville Anderson in the geology building at the University of Glasgow, May 2013.

I never dreamed that islands about 50 or 60 miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case. It is the fate of most voyagers, no sooner to discover what is most interesting in any locality, than they are hurried from it; but I ought, perhaps, to be thankful that I obtained sufficient materials to establish this most remarkable fact in the distribution of organic beings.

A visit to the Galápagos is indeed something to be thankful for, not only for a young naturalist of the 19th century, but also for an interested amateur of the 21st. And I could not have gotten there by myself. Thanks, Somerville!

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