We hear the island before we see it. Raindrops pelt my face like bullets as we zip across the Amazon Basin in a motorised skiff towards the primate sanctuary known as Monkey Island.
A low howl vibrates through the jungle, a sound so otherworldly it could hail from the heavens. But no, it's coming from that tree over there, where a flame-haired howler monkey heralds our arrival.
The islanders are super-excited because we have brought bananas. To see their reaction is to understand what "going bananas" really means. A rakish black spider monkey somersaults down to shore and strikes Saturday Night Fever poses for our amusement. The howler keeps up a deafening racket. Titchy white and black capuchins cuff the bigger primates and steal their fruit. It's like watching a family feud, but with more screaming and acrobatics. It's so fascinating I forget all about the rain.
This is not the Amazon I remember. Three years ago, visiting this region of north-eastern Peru in the dry season, it was a far more barren world. The annual floods had trashed the landscapes they left behind and wildlife was surprisingly scarce for a place renowned as a cradle of biodiversity.
But now in May, at the end of the wet season, the Peruvian Amazon is a jungle of mirrors - surreal and beautiful and breathtaking in equal measure. And this time around, there are animals everywhere.The contrast puzzles me until I stumble across this perfect explanation by the Greek philosopher Heraclitus in the ship's library: "No man ever steps in the same river twice, for it's not the same river and he's not the same man." How very wise.
It's not the same boat, either. This time I'm aboard Delfin I, the original luxury Amazon cruiser launched a decade ago by Peruvian couple Aldo Macchiavello and Lissy Urteaga. Today it is one of several riverboats plying the waters between Iquitos, the gateway city to the Amazon, and the Pacaya-Samiria National Reserve, Peru's largest wildlife sanctuary.
The boat was renovated in 2010 to provide each of its four berths with deep balconies. It's this feature, the private viewing deck onto untamed landscapes and exotic creatures, that distinguishes the Delfin from its competitors. The cast and crew are different, too, of course. My fellow adventurers, all American, include a banker, a doctor and a Don Draper-esque ad agency owner. But the most important person in this story is our amazingly talented guide.
Sandro Soria Del Aguila has, like his namesake, the eyesight of an eagle (águila in Spanish). He has lived on this river all his life and learnt since childhood how to mimic the call of everything from botos, the pink river dolphins, to elusive dusky titi monkeys. What he doesn't spot with the naked eye he can always flush out of the forest with trickery.
Thanks to his exceptional skills, on our début morning safari on the Tahuayo River, an Amazon tributary, we see our first three-toed sloth within minutes and our second shortly afterwards. Contrary to reputation the second one is remarkably agile, slowly craning its cartoonishly long limbs upwards to grasp ever-higher branches.
Sloths are intriguing - I could tell you fascinating things about how their fur supports dozens of species of fungi, symbiotic algae, moths and microorganisms, or how harpy eagles crush sloth skulls with their talons - but they are not handsome animals. Local ribereño people believe pregnant women should not look upon a sloth lest their child be born with the face of one.
Birdlife in the Amazon is as whimsical and colourful as a children's fairytale. The air is alive with masked crimson tanagers, yellow-rumped caciques, red-capped cardinals, crimson-crested woodpeckers, striated herons and a giant cocoi heron gliding in front of us like a winged escort.
An afternoon excursion on the Yanayacu (black water) River is waylaid by a troupe of performing botos. They swim rings around the skiff, often in tandem, performing a peekaboo panto in which they always manage to vanish just as we press our camera shutters. On film they are simply musk-pink slashes on a milk-coffee river.
A woodpecker hammers at a kapok tree as a yellow-headed caracara swoops into frame and settles on a nearby branch. Directly above us, a dusky titi monkey sits alone on a branch, its grey tail dangling straight down like a fluffy sword. Del Aguila is amazed. The dusky titi is a social animal that rarely travels alone, he explains, and almost never loiters in one spot. To find one posing calmly for our cameras is a bit extraordinary.
We spot many more sloths. When Del Aguila points out the umpteenth one, languidly munching scarlet kapok flowers in the late afternoon sun, GT's photographer, James Geer, cries out, "This is ridiculous!" He's right. This wilderness seemed so lifeless when I last visited and now, thanks to Del Aguila, we can barely move a hundred metres without spotting something remarkable.
On the home straight, in the magic hour, I spy the Delfin in the distance against a wall of green and decide our ship is very simpático with the jungle. Like a tall village house, with open sides and a roof of irapay palm-leaf thatch. It's made from the same local hardwood, anacaspi, as the much humbler dugouts that ply these waters.
Back on board, reclining on the balcony with a beer to celebrate a wildly successful first day of animal-spotting, my attention is diverted by a trio of dolphins leaping out of the water nearby. This is not the sluggish surfacing we've seen previously but the full, Sea World extravaganza of synchronised, aerial arcs. Again, ridiculous.
Dinner is served in the glass-walled dining room where staff have been busy decorating our table with placemats and napkins, and a still-life arrangement of palm-fibre fish, carved turtles and an armadillo.
The waiters spoil us with white-gloved service, which is probably unnecessary in the jungle, but all part of the Delfin experience. As crewmember Freddy Parano assures us when we first step aboard, "Everything you need, we are working for you all day."
On the menu: iceberg lettuce cups filled with mango, bacon, fried plantain and crunchy mocambo nuts; chicken with olluco potato and a castaño nut sauce, with a slightly superfluous side of fettuccine in a pijuayo, or peach palm, sauce.
There's no shortage of Amazonian inspiration on the Delfin menu and chef Israel Ijuma knows his exotic ingredients well enough to blend them seamlessly and often deliciously into our daily diet. Other standout dining moments during the three-night cruise are a ceviche of doncella wrasse with a tomatolike sauce made with cocona and a foam of charapita chilli, and fish steamed in banana leaf with fried manioc, jerky and a vinaigrette of chonta, or palm heart.
After dinner there's an impromptu show by barman Martín Tamani Carrion, restaurant manager Jose Enrique Yaicate Murayari and Parano. It turns out the Amazon's got talent. The Lady Killers, as they call themselves, perform instantly likeable hits such as "Welcome to Iquitos", a jaunty rendition of "Guantanamera" and another song about how important it is to protect the Amazon. That last one features panpipes, which is not ideal, but Murayari's voice is so sweet it makes up for any indiscretions. He's the best singer but Parano has the best dance moves.
Life on board is luxurious compared with everyday living standards on the Amazon. Two of the four suites have whirlpools built into their balcony decking and all cabins feature beds dressed in crisp white sheets and waffle-weave blankets, often crowned by a striking towel-art arrangement.
The cabins' sleeping and sitting areas have uninterrupted Amazon views through floor-to-ceiling glass. The well-equipped dressing area, vanity and bathroom (with walk-in shower) are tucked away in the more private rear of the cabin. Delfin thoughtfully supplies its own-brand moisturiser and a combined sunscreen-insect repellent that becomes an indispensable part of our daily routines.
The covered roof deck is the ship's social hub. It's where we gather for talks, tropical fruit presentations and cocktails prepared by Carrion, who makes a mean Pisco Sour and, for one passenger (not me), a double Johnnie Walker Blue each morning at 11.30.
Our privileged existence is in glaring contrast to the lives of most river-dwellers. In Iquitos, the isolated frontier city, the trials of living beside the world's greatest floodplain are on display for all to see. The streets of Belén, an overcrowded, desperately poor neighbourhood, are crammed with neat rows of tents and tiny timber huts erected hastily after the monstrous river rose 13 metres last wet season and left thousands of outlying villagers homeless. I'm told this was the third consecutive year of record floods, which seems a particularly cruel trial for people who have so little to begin with.
We see first-hand how ribereños live on a morning visit to Puerto Miguel, a community beside the Yarapa River downstream from Iquitos. Delfin began working with villagers here in 2007, encouraging them to make handicrafts that the company buys to decorate the ship (hence the colourful dining-table settings). Now more than 40 women, collectively known as "Yarapa butterflies", create giftware that they also sell from a shopfront in the village. The money raised helps buy school supplies and textbooks for more than 200 pupils, as well as first-aid supplies for the community.
At Puerto Miguel's makeshift jetty we hang back to admire the sight of children ferrying themselves to school by dugout. They tie up their canoes, bid us buenos días and plod off to school along the muddy, waterlogged main street. We disembark onto a series of rickety planks that lead from the shore to a simple stilted house where we will have breakfast. Local artist Meliton Fababa and his five-year-old daughter, Talita, host us while his wife keeps busy out back in the kitchen, cooking in a haze of blue smoke.
The eight of us sit around a rough-hewn table dressed with a synthetic lace cloth. Our napkins have been rolled, tied and fastened with dolls made from raffia-like fibre. Carrion loads the table with cassava bread rolls stuffed with bacon and egg, purple sacha papa potato rolls with ham and cheese, chocolate muffins and mocambo biscuits. There's less chat than usual at meal times as we take in our surrounds.
The sodden road with its sluggish traffic of ducklings, chickens and the occasional villager sloshing by in gumboots. The interior of the Fababa home, its bare timber walls decorated with a poster of the alphabet and no fewer than five calendars, including two from the local MP. Washing lines hang either side of the main room, which is furnished sparely with rough benches and low tables, a red-and-white striped hammock, something large and lumpy hidden beneath a blue tarpaulin, and a stack of oars in a corner. The conditions are so abject it's difficult to imagine much of a life here, but Señor Fababa tells me four of his children have gone on to study and work in Iquitos and Lima.
Delfin also works with other Amazon villages, enlisting local people as guides when the ship visits communities such as San Isidro, Casual and San Francisco. Villagers take turns at guiding so everyone gets a taste of working in tourism.
At the start of a sweaty walk through the Casual Forest a man named Federico, from the nearby hamlet of San Jose de Sarapanga, greets us with a machete. He has been assigned to show us around his backyard or, more precisely, to scamper off into the forest and unearth bizarre creatures for us to ogle and photograph.
Del Aguila leads the way, pointing out various jungle plants and their medicinal properties: the antiseptic benefits of the dragon's blood tree, a fig sap that's said to cure intestinal parasites, and the anti-inflammatory bark of the cat's claw vine, also used to treat diabetes.
Federico's first prize is a spotted-leg poison frog, followed swiftly by a miniature poison-dart frog, its belly mosaicked with intricate patterns.
For his next trick Federico finds a pink-toed tarantula, which Del Aguila, alarmingly, lets climb all over his hands and arms. He claims there is no danger, so six of us volunteer to have the tarantula creep over our bodies. Its tiny padded feet tiptoe softly on my flesh.
We've had a running joke with Del Aguila that we're not leaving the Amazon without seeing an anaconda, and he has patiently explained how unlikely this is because the largest snake in the world tends to live in remote rainforest areas. But Federico proves him wrong by finding a juvenile snake strangling a tree. Even in adolescent form the anaconda is a menacing sight, flicking its tongue at us as it unravels slowly from the trunk in our direction. We don't linger.
At the end of the hike we come across about 40 tourists in identical beige safari outfits and I'm reminded how lucky we are to be in such a small group. We see few other travellers. One afternoon we wave to some backpackers and their guides combing a riverbank in dugouts. Commuter boats, or peque-peques, ferry people between settlements. And one morning a three-storey barge, the Henry, emerges from the drizzle, its roof packed with plastic-covered motorbikes bound for Iquitos, and its lower decks packed with passengers. It's an evocative sight, very Amazon.
Piranhas are an unavoidable topic in these parts. Their legend precedes them and guides such as Del Aguila spend a lot of time dispelling myths. No, they are not man-eaters (though he concedes blood in the water may "excite them to madness", as US president Teddy Roosevelt claimed in a best-selling memoir about his travels to Brazil in 1913). To prove the point Del Aguila takes us fishing on the Nauta Caño river, hooking our lines with rotten beef and urging us to whack the water with our rods to rouse the fish to bite.
We pluck piranhas from the river with astonishing ease. They have angry red flanks and nightmarish teeth, but they are very small and, as we discover later that night during a pre-dinner snack, they taste delicious. The flesh is clean, white, sweet - extremely good eating. They probably say the same about us.
As darkness falls Del Aguila sets up a spotlight and we trawl the Nauta Caño for caiman. It's a rare unsuccessful mission - we find only one tiny, not-at-all-fearsome reptile - but that's fine because we're more preoccupied with the setting.
It's beautiful here - "like a floating paradise!" sighs one passenger. Del Aguila cuts the engine and we sit mutely as the sounds of the Amazon crowd in. The rainforest comes alive with squeeps and croaks, whirrs and buzzing, tinks and grunts and the deep-throated "gronk" of giant monkey frogs calling for mates from their treetop lairs. Fireflies blink by the banks. The night sky blazes with neon stars, a carpet of sparkle that unfolds gradually as the last light fades. It starts with Venus and Saturn and culminates in a high-definition Milky Way that leaves us awestruck. All set to a soundtrack Del Aguila calls "the symphony of the jungle".
One morning I wake to find Captain Toribio Arista Díaz has parked our small ship beside a plantain field with a view across a vast brown torrent of turbid water. This is the junction of the Ucayali and Marañón rivers. We can't actually see the precise point where the rivers meet, but we can appreciate the symbolism of the captain's gesture. This murky intersection is generally agreed to be the official start of the Amazon.
From here, the world's mightiest river surges west across South America to empty into the Atlantic, some 4,000 kilometres away. (The actual source of the Amazon is much further away, more than 5,600 metres high in the Peruvian Andes, on the snow-streaked Nevado Mismi in the Arequípa region. From little trickles, vast rivers grow.)
We mark the last day with a tranquil kayak down another arm of the Amazon, after which we finally get our chance to dive into its murky waters. Our baptism in the mighty river.
As we cruise in the rain back to Iquitos to disembark, I chat to Carrion over a coffee at the bar. He starts two weeks' leave today, which I imagine he must be delirious about given that, when on duty, crew members rarely seem to have any time to themselves.
They clean our rooms three times a day, surprise us with towel art (swans, sloths et cetera), answer our incessant questions, clean our muddy shoes, decorate the dining room, fetch anything, do anything. It's incessant, smiling service from dawn until bedtime.
But Carrion sets me straight. "You pay to come here and see the Amazon," he answers in his slow, deep voice. "Whereas I get paid to be here. Do you understand? Estoy feliz. I am happy."