He may have had what Richard Dawkins calls "the most powerful idea ever", but Charles Darwin was, by the standards of today's environmentally sensitive tourists, a vandal.
Indeed, when HMS Beagle landed at the Galápagos Islands in September 1835, the local wildlife must have wondered whether the ship's naturalist was there simply to have a laugh at its expense.
Pity, in particular, the giant tortoises. In his Journal of Researches, Darwin boasts that "I frequently got on their backs, and then, upon giving a few raps on the hinder part of the shell, they would rise up and walk away; but I found it very difficult to keep my balance". When he wasn't straddling them, he was having them for Sunday lunch ("the breastplate roasted... is very good; and the young tortoises make excellent soup") or simply teasing them: "I was always amused, when overtaking one of these great monsters as it was quietly pacing along, to see how suddenly, the instant I passed, it would draw in its head and legs, and uttering a deep hiss fall to the ground with a heavy sound as if struck dead." Cheers, Charles. Nice one. Pop back any time.
Things are, of course, very different now. Darwin cemented his reputation 24 years later with the publication of On the Origin of Species and – thanks in particular to the 13 different species of finch he observed there – the Galápagos archipelago is forever associated with his name, a geographical embodiment of the theory of "natural selection".
The giant tortoises have since become icons – as indeed has Darwin, who even features on the back of the £10 note – and these days the fate of Lonesome George (the last testudinal survivor from the island of Pinta) provides a sobering lesson on how fragile this unique ecosystem really is.
Tourists, too, have learnt to modify their behaviour. But working out how visitors fit into the Galápagan scenery – assuming we should be here at all – has proved complicated. Ecuador, which owns the islands, declared them to be a national park in 1959; Unesco granted them World Heritage Status in 1978, with the surrounding waters later being designated a marine reserve. Strict residence and fishing controls were introduced in 1998; programmes to eradicate feral goats and pigs imported by mariners are still being undertaken. Yet of the 13 main islands, five (Baltra, Floreana, Isabela, San Cristóbal and Santa Cruz) are now inhabited by a total of around 40,000 people, most of whom are involved in the tourism industry. Last year, Unesco put the archipelago on a less-desirable register, its World Heritage in Danger list, citing "invasive species, growing tourism and immigration" as the main threats.
Of course, tourists generate plenty of cash for the local economy when they visit the Galápagos islands on cruises and tours. They also pay a US$100 (£55) park entrance fee. But the inexorable rise in visitor numbers – from an estimated 41,000 in 1990 to more than 100,000 in 2005 – raises its own difficulties.
Take La Pinta, for instance: last month, I was booked to join this new 40-passenger motor yacht on her maiden Galápagos cruise. However, the night before we were due to leave Ecuador for the islands, passengers were told that the relevant National Park permissions had not been obtained: La Pinta would remain stuck in port at Guayaquil on the Ecuadorean coast.
On the one hand, the cancellation suggested that tourist numbers were being scrutinised and controlled, albeit at ludicrously short notice. On the other, the fact that the yacht was then authorised to sail a week later spoke volumes about the pre-eminent value that the Ecuadorean government puts on tourist dollars in the region. The non-departure of La Pinta was, briefly, a national news story: the Director of the National Park was sacked by the Environment Minister... and I suddenly found myself in need of a new boat.
Darwin, a martyr to seasickness throughout his five-year voyage on the Beagle would have appreciated being stranded. "I loathe, I abhor the sea and all ships which sail on it," he once wrote. His initial impressions of the Galápagos islands were equally dreary: "Nothing could be less inviting than the first appearance. A broken field of black basaltic lava is every where covered by a stunted brushwood, which shows little sign on life."
These days, of course, visitors arrive by air (two hours from the Ecuadorean mainland), but the view is still a sobering one: dark and bleakly mysterious, the islands prickle the calm of the Pacific with a brooding menace, the black volcanic rock scraping upwards into mist-shrouded calderas.
From the sky, the archipelago seems remote, untouched; 1,000km of open water separates these islands from the coast of South America. I saw no houses, no boats, no single sign of life until we began to bank down towards the strip that marks out the tiny airport on Baltra island.
Baltra is a nugget of rock to the north of Galápagos's main inhabited island, Santa Cruz. The two are separated by a tiny channel, so the airport transfer involves a trip over the water by skiff (fare $0.80; the US dollar is the national currency). Brown pelicans roosted in the reeds by the shore, gulping at us as we passed; magnificent frigate birds wheeled overhead like computer-generated pterodactyls.
From the landing stage on Santa Cruz, I was driven into the interior by Raúl, who works at the Galápagos Safari Camp, a newly opened lodge up in the highlands. Everything started small on our journey; the red soil was spattered with tangles of bleached-white wood, cactus plants and bright green grass. My first close encounter was with a cricket, then a bright yellow butterfly and a flock of finches (the birds so tame that Raúl had to beep his horn to get them to fly out of our way). But as we climbed into the hills, the vegetation grew in height, rising lusher and larger with every metre of elevation.
The Galápagos Safari Camp lies at the end of a dirt track: the last farm before the national park begins. The view from the sleek, modern curve of the newly constructed main building is astounding: a broad sweep of the coast, pricked with conical hills, with the neighbouring islands looming beyond the coast in sharply defined gradients of grey.
My "room" was set below – one of eight luxury tents imported from Australia by the owners, Stephanie and Michael Mesdag, who hope to lure visitors here for a spot of R&R at the beginning or the end of a cruise around the islands.
"Safari tents are so suited to this landscape," said Stephanie. "Look at that view – don't you expect a lion to come out of it?"
The prospect of a Galápagos lion padding through the scalesia and pale green palo santo trees might stretch credulity, but the Safari Camp is nevertheless a place of fantasy – the perfect opportunity to take stock of the islands for the first time. I arrived to tropical dampness and an almost immediate, sluicing downpour that left everything slick with a glistening sheen. The hot, wet season runs from January to June here, then gives way to a chillier, dryer period, when the islands are enveloped by a mist called the garúa. It's a weather system unique to the Galápagos: the product of the cold underwater currents that meet here on the otherwise season-less equator. In the evening, as I enjoyed an exquisite meal of seared tuna served on the lodge's veranda, the darkness fizzed with sounds of insect life; by next morning the birds had taken over, letting rip in a mighty dawn chorus.
Later that day, in lieu of La Pinta, I found myself aboard the vast Galápagos Legend, a 98-passenger luxury cruise ship that calls at Santa Cruz every Tuesday and Friday. Of course, in this context, bigger is not necessarily better. The Legend is a very traditional cruiser, decked out in plastic wood and vintage brass, with vast buffet meals and evening entertainment laid on for the guests. The boat's sheer mass doesn't seem in keeping with the twisted, haunting scenery, but it does have the benefit of getting round the islands quickly and efficiently.
Indeed, I soon learnt that it doesn't really matter what sort of boat you take round the archipelago. Ninety-seven per cent of the islands' area lies within the national park, and there are very few places where visitors – accompanied, of course, by a registered guide – are allowed to disembark. So whether you travel in a small group on a tiny charter boat, or aboard a behemoth such as the Galápagos Legend, the landing sites are the same, the routes inland carefully prescribed.
In our case, we were ordered into small teams – Albatrosses, Boobies, u o Cormorants, Dolphins, Frigates, Gaviottas (gulls) and Iguanas – for our twice-daily disembarkation via pangas, small motor launches. Thankfully, I was placed with the Frigates; I don't think I could have lived with the ribaldry that might have accompanied being a Boobie.
There are boobies – of the blue-footed kind – everywhere in the Galápagos islands: hanging round cliff walls, arrowing into the sea for fish. The first time I saw one up close, I made my first Galápagos mistake, frantically snapping away with my camera, desperate to bag a decent digital memento. Had the poor bird been able to talk, it would no doubt have pointed out that there were plenty more of its kind about, that there was no need to panic.
And that's the extraordinary thing about the fauna of these islands: yes, you're encountering animals that are often fantastically rare (although boobies can be found elsewhere in the Pacific), but here they're all over the place – and tamely tolerant of tourists.
Every evening aboard the Legend, we were briefed as to where we would land the next day, and what we would see. And unlike on most other nature treks, the caveat "if we're lucky" was never uttered. Instead we were showered with the prospect of outlandish encounters: "Tomorrow, ladies and gentlemen, you will see flightless cormorants, sealions, flamingoes and penguins." It was pronounced as fact, and it invariably turned out to be true.
Alongside a crash course in nature photography, some mental snapshots: marine iguanas piled on top of each other near the mangrove swamp on Fernandino, sneezing out saltwater as we pass, their grey bodies all but invisible against the lava (the stench is appalling); snorkelling off the domed island of Bartolomé as Galápagos penguins shoot past shoals of parrotfish grazing on the coral; flightless cormorants stretching their stunted wings on the rocks of Fernandino as fur seals slumber nearby; sea turtles bumbling along cropping algae from the sea floor; sealions everywhere – swimming with us, fighting with each other, or just lolling on the beach.
At night, the lights of the Legend attracted plankton to the surface, which in turn lured flying fish, which themselves arouse the interest of sea lions, and then Galápagos sharks: an entire food chain laid out before us in the gloom. And alongside the big stuff, there were smaller moments to cherish: flocks of finches pecking for seeds; the shy but spectacular Galápagos dove peeking out from behind a bush; warblers, mockingbirds, herons and woodpeckers; sally-go-lightly crabs in their bright livery.
We met our first land iguanas on the island of Isabela. Cast in fiery colours, they stood stock-still in the shade, unperturbed by our presence, as if rubber versions had been placed there earlier in order to trick unwary tourists. Darwin didn't stand on ceremony: he entertained himself by pulling one iguana out of its burrow by the tail, which apparently caused it to be "greatly astonished".
Get past the exotic, once-in-a-lifetime animal encounters, though, and it's the landscape that leaves the most lasting impression: the red, iron-rich sand of Rabida, the cracks and fissures of the lava on Fernandino, the blow-holes and rock pools on the shores of the island of Santiago, the monochromatic splendour of the islands at dusk.
Even in my last 24 hours on the islands, back on Santa Cruz, I witnessed things that are in themselves worth travelling thousands of miles to see: vivid pink flamingoes sifting for krill in a lagoon near Bachas beach; a sea turtle heading back to the sea, having just laid her eggs up on the shore; a vast hollow tube of lava, big enough to walk through and hundreds of metres long.
Nothing, however, beats your first encounter with a giant tortoise in the wild.
You can see baby giant tortoises at the Darwin Centre, a captive breeding station near Santa Cruz's town of Puerto Ayora. It's here that they are reared before being reintroduced to their islands; it's also here that Lonesome George ploughs his solitary furrow.
Darwin wasn't alone in developing a taste for tortoise meat. In the 19th century alone, at least 260,000 of this famously long-lived animal were taken from the islands for food. Of the 14 subspecies once in existence, those from Fernandina, Floriana and Santa Fé are long gone – eaten by humans, or wiped out by rapacious, non-native species – and when George croaks, the species from Pinta will join them. The outlook for the other types is better: approximately 2,000 tortoises have now been successfully reared and returned to the wild.
The Darwin Centre's efforts are laudable, but the problem with seeing baby giant tortoises is that they look, well, just like normal-sized family pets. It's in the highlands that you see real thing. (Indeed, on the way there, we had to wait as one passed in front of our bus, which should really have prompted the old joke: "Why did the tortoise cross the road?" "It's a long story.")
When we finally arrived at a farm lying at the edge of the tortoises' protected area, they weren't exactly hard to find: a couple were parked like Minis in a field; another was half-submerged in a pond with a duck standing on its back. I hadn't been prepared for quite how large they were, or how grave they looked as they munched their way through the landscape.
Darwin got one thing right (all right, he got quite a lot of things right): they really do make a hissing noise when retracting their necks. But according to our guide, they make no other noise. Apart, that is, from a low, sonorous groan while mating. Here, the guide mimed one tortoise climbing on top of another one and did an impression: "Uuuuuuuhhhhhgggggggggrrrrhhhh!"
Quite a good impression, as it turned out, because a few minutes later, I was startled to see a vast tortoise crashing out from behind a tree and tearing along at an impressive lick behind an unsuspecting female, which it immediately mounted. As we all captured the moment for eternity on our cameras – feeling, in my case, slightly grubby in the process – the chirrup of finches was briefly matched by the beep and snap of autofocus and camera shutter, and then a long moan: "Uuuuuuuuuhhhhhgggggggggrrrrhhhh!"
After a while, we left them to it. I sincerely hope that Darwin would have done the same.
GALAPAGOSH! WHY THE ISLANDS ARE SO VARIED
The Galápagos Islands lie on a volcanic hotspot – the meeting point of the Nazca and Cocos tectonic plates – and are drifting gently south-east. The oldest island is Española, which geologists reckon is more than three million years old, and lies to the east. The youngest two are Fernandina and Isabela (the largest land mass in the archipelago, with a spine of five active volcanoes). These lie to the west, nearest the hotspot, and are just 750,000 years old. The relative differences in age account for the islands' characters: lava, cacti and simple food chains in the west; fertile soil, greenery and cliffs full of birdlife in the east.
But just why are the animals so tame? Because the islands were never attached to any major landmass, all the animals now endemic to the archipelago either swam or flew here and – in the absence of any competing fauna – occupied all the available evolutionary niches. The finch took on the role of woodpecker and vampire bat; tortoises graze like cattle. Because there were no predators equivalent to humans for them to be scared of, they are still remarkably unperturbed by our presence.
Direct flights to Baltra and San Cristóbal airports in the Galápagos Islands leave from Guayaquil on the Ecuadorean mainland and are operated by Tame (00 593 2 290 9900; www.tame.com.ec ) and AeroGal (00 593 2 294 2800; www.aerogal.com .ec). A transit card costs $10 (£5.50) and the park entrance fee is US$100 (£55). Guayaquil is served by KLM (08705 074074; www.klm.com ) via Amsterdam; and Iberia (0870 609 0500; www.iberia.com ) via Madrid.
To reduce the impact on the environment, you can buy an "offset" from Abta (020-7637 2444; www.reducemyfootprint.travel ).
The 63m luxury yacht La Pinta started operation on 14 March. The vessel accommodates 48 passengers in outside cabins, all with picture windows. Bales Worldwide (0845 057 0600; www. balesworldwide.com ) offers weekly departures as part of a 14-day La Pinta Cruise holiday, from £3,790 per person. The price includes return KLM flights from Heathrow via Guayaquil and Quito, B&B accommodation and sightseeing in Quito and full board on La Pinta, as well as all fees. A special Bales charter onboard the vessel takes place on 28 October, escorted by a member of the Bales family and the naturalist Greg Estes, a leading light in the protection of the Galápagos marine environment, priced at £3,999 per person. Bales also offers two-night pre- or post-cruise stays at the new Galápagos Safari Camp for £220 per person, half-board.
Galapagos Safari Camp, Santa Cruz Island, Galápagos, Ecuador (00 593 9179 4259; www.galapagossafaricamp.com ). Double tents start at US$400 (£210), half board.