Sitting on the deck of a small river-cruise ship, I listened to the never-ending sounds of the Amazonian rain forest. Beside me was a retired business executive, a fellow passenger whom I had just met the day before.

As the sinking sun bled into the darkening sky and the riverbanks along this tributary of the Peruvian Amazon turned from green to black, he told me of his days in Lagos in the 1970s and Dubai in the 1990s, then lapsed into silence.

The moment was all the sweeter because we were playing hooky from an outing to view nocturnal birds, opting for perfectly chilled white wine over mosquitoes.

Our solitude was interrupted when a young man dressed in army fatigues, a holstered gun at his hip, strolled by. My worldly shipboard friend raised a quizzical eyebrow.

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The armed escort, fortunately, was not a response to a specific threat. In 2009, a luxury Aqua Expeditions cruise ship had been boarded by armed pirates, who robbed the passengers of cameras, cash and jewelry.

Ever since then, the Aqua Amazon ship (on which I was traveling) and its sister ship, the Aria, have been accompanied by three armed guards, part of a Peruvian river-protection strategy that includes a green speedboat marked Policia de Tourismo that follows the ship. So far, there have been no other incidents.

Remote, and pricey, luxury

Luxury cruising through the Peruvian Amazon region is a rare and expensive experience, not surprisingly, since operating a posh vessel in an area so remote is a logistical challenge.

In addition to Aqua Expeditions, which operates the 12-suite Aqua and the 16-suite Aria, there is Delfin Amazon Cruise, which also has two small ships (one with only four suites).

Our boat had just 24 passengers and a design so chic and minimalist it was once a backdrop in a Condé Nast Traveler fashion spread, with models covered in bangles, scarves and flowing dresses draped on the deck chairs.

In contrast, my cruise mates wore lightweight khaki clothing and sensible shoes. They were intent on seeing as much of the rich Amazonian flora and fauna as possible on our 4-day trip.

For the most part, my fellow travelers were experienced, passionate, knowledgeable animal lovers and birders, among them a group from Natural Habitat Adventures, a travel partner of the World Wildlife Fund. Most were armed with state-of-the-art binoculars and telephoto lenses the size of bazookas.

A nature-travel neophyte, I was equipped with an iPhone camera. I soon learned, however, that even the most serious wildlife lover is prone to cruise antics, such as a conga line fueled by pisco, a potent grape brandy.

The excursions offered a strong sense of place. We explored estuaries and were enveloped in the humid rain forest. The sun beat down; we slathered on bug repellent or, alternatively, pulled on ponchos during sudden rainstorms. We visited a local village where we sat in a one-room school in pint-size chairs, listening to the children sing.

Then we returned to the creature comforts of hot showers, air-conditioning, an attentive crew, immaculate housekeeping and nonstop dining on everything from Thai food to local fare like Amazon bass, tiger catfish, Andean trout and a dizzying amount of camu camu and other local fresh fruits.

Gazing at the water, I saw the familiar elegant arch of a dolphin. Until this trip, I did not even know that such creatures as pink river dolphins existed.