The centre for military action in the region, and therefore the place to find a platoon on jungle exercises, is a frighteningly remote town called Riberalta, a mere 65 hours by road from La Paz, Bolivia's capital. Previous 35-hour trips on Peruvian death-traps had cured me of any interest I might have had in South American buses, so my quest was to get to Riberalta by alternative means.

A wiser person would have flown all the way; after all, the local military has direct flights direct from the city to the north. But this sounded far too easy and, full of the pioneering spirit with which most young travellers are brimming, I decided that a boat was a much more romantic idea.

OK, some flying was involved - anything to cut out 24 hours of flota travel (a medium-sized bus) on the 'death road'. So I arrived in the quiet but cottoning-on town of Rurrenabaque with joy. The sheer novelty of landing on a grass airstrip surrounded by exciting looking jungle foliage gives you that wonderful Famous Five feeling, as though an adventure is just about to begin and you are the one to start it. The town itself is a pleasant place; its inhabitants wander leisurely along dusty streets between the palm-roofed huts and raised wooden walkways, mostly ignoring the odd stray tourist, upon whom the town's economy is rapidly becoming dependent. The women wear a tropical version of traditional Bolivian dress: an under-sized bowler hat, overly tight slip-ons and only three skirts as opposed to the eight or so of the altitudinous altiplano. The men prefer vests. Mountains loom for postcard shots in the background and the river Beni zooms past with its supply of moustachioed suribi (catfish), urethra fish and driftwood.

Fighting the urge to abandon it all in favour of a hammock and a bottle of pampeño (a potent if dangerous caramel-tasting alcohol, claiming to be rum) I set about the task in hand - to get a boat up to Riberalta. Armed with a bilingual friend (Pablo) and a winning smile, the search for a guide began. It soon became apparent that any number of tour companies were willing to whisk us off down river to wade though the pampas to hunt for anacondas or to investigate hallucinogenic plants in the jungle, but no one was willing to go north. "Nothing goes up river now," said a bemused looking agency guide, "there is the road for that". Only foolish journalists and the occasional smuggler would have any interest in travelling so obviously against the flow it seemed. Despondency, soothed by food and a blisteringly beautiful sunset, found René, a familiar face from a previous visit, chuckling on the riverbank with his cronies. All credit to Pablo for the following interactions as I lost all grip on the conversation once it got onto outboards and tarpaulins. However, after hours of haggling and disappearing to 'see a friend', René became our guide and we had a canoe, a motor and some shopping to do.

Shopping in the market in Rurrenabaque is limited to a small street of shabby but colourful market stalls. People called out our names as we walked by and after three days we were the talk of the town. We had to buy everything. This included saucepans, rope, food and apparently essential little bags of food colouring. As we traipsed through the pouring rain laden with cheap goods and covered in mud, I realised that perhaps this was not going to be a leisurely float upstream. The last retail point of call was at what appeared to be the local nursing home. An elderly man sat in a rickety rocking chair on his porch tended by an array of unevenly aged women, looking more deep south than South American. To our surprise René immediately began to haggle over prices. Prices for what was not evident until the aged Don Juan shouted at the eldest woman who swiftly reappeared with a vast assortment of fishing hooks.

Tackle complete, our shopping was done and the loading began. That afternoon we were ready and with our trousers rolled up and flip-flops on, we waded out and attempted to arrange ourselves in the low boat. René steered, in front sat Juan, his inanely grinning sidekick; then a large amount of luggage and other equipment. Finally, in the prow, dodging leaks and stray machetes Pablo and I jostled for space. I was sad to leave Rurrenabaque as it is a wonderfully lacksadaisical and lovely place. This was mixed with a fear of the unknown that lay ahead as we set off with only the vaguest of plans, a grudging 10 days off from my editor and a promise from René that he would get us halfway in a week. The Beni is a fast flowing river banked by endless jungle potentially crammed with deadly snakes, jaguars and omnivorous pigs but as it spread around us, and as we laid back to watch the birds circle above the canopy with the engine softly putting in the background, all was well.

We spent seven days motoring up river, setting up camp on sand banks, sleeping under the stars and eating freshly caught catfish. I was very disappointed not to see any jaguars, despite the guide's assurances that they were inches away at all times, just waiting to leap on you. There was plenty of other wildlife on display to keep me occupied. At night, vampire bats - 'vengan los vampiros' - and fireflies flitted above our heads while during the day flamingos, pelicans, macaws and storks took to the skies.

On one trip into the forest we followed a monkey troop and returned to find sidekick Juan deep in conversation with a bare-chested, bare-foot man who was brandishing an ancient rifle. From somewhere behind him rose a hideous high-pitched shrieking. This disconcerting vision was quickly revealed to be a jochi (wild pig) hunter who had brought his pet baby howler monkey along for the ride. Upsettingly, that is probably the closest I will ever get to one. Also upsetting was our guide's later insistence on turtle nest robbing. Between him and his friend they gathered half a sack, roughly 70 eggs, and they were not the only ones doing it. We passed a whole family clinging to a tatty raft as they made their way up river, stopping whenever they saw the telltale tracks on the sand. The Bolivians had no qualms about taking the eggs and as yet very little, if anything, is being done to prevent the steady depletion in the region. However, it struck me also how desperate a family must be to spend its life drifting up and down river to collect eggs. They were just six people of the millions who live well beneath the poverty line in Bolivia. Almost everyone I met lived from hand-to-mouth, hunting, farming a little and bartering for goods. In my 10-day trip to Riberalta, I spent $300, roughly 10 times the average monthly wage and that was doing it on the cheap.