It's the first afternoon of our four-day paddling trip down the Manonbolo River, in Western Madagascar, when a giant chameleon drops from overhanging branches into my canoe.
At the back of the canoe, Dada, our chief river guide and expedition chef, who spotted the reptile sunning itself on a branch, laughs as the 60 centimetre-long "giant" settles itself on the rucksack stored behind my back.
"Looks like Pelamana has given us his blessing," says Dada in French, referring to our guides' prayers to the ancestral river spirit with which our canoe trip began, near the ramshackle village of Ankavandra.
"Let's take her to show the others," he adds.
As we paddle and occasionally claw at the sandy bottom to propel ourselves down the shallow river to reach the eight others in our group, I wonder whether the colour-changing hitchhiker behind me is turning blue like the backpack it alighted upon.
Then, as we get to within 200 metres of the other canoes, I feel it shimmy up my back and onto my shoulder, turning me instantly into a Malagasy Long John Silver.
Finally, still not content with the conditions of her carriage, she hops onto my hat, where she sure-footedly installs herself for the next 15 minutes, like a scaly figurehead on a pirate ship.
In a country where little is done, even by the president, without consulting a shaman, my encounter with this presumptuous chameleon, seems to augur well not just for our journey down the Manonbolo but for our whole 21-day World Expeditions' Madagascar Adventure.
Reaching the others in our tour group, largely drawn from Australia but including a 51-year-old Israeli engineer from Tel Aviv and English couple Julie and Riant from Kettering, I pose for pictures, beaming from ear to ear.
On this, our first on the river and fifth day overall, we've begun to fall into a rhythm, not simply of paddling for several hours a day but of joshing each other as we do so.
Retired Canberran public servant Andrew is always ready with a salient fact or story from another trip while Riant, a 40-year-old travelling in spite of ongoing treatment for a brain tumour, has an '80s pop song for every occasion.
To get to the Manonbolo from the unappealing capital Antananarivo, we have driven for a day and a half, the latter part of which involved the type of four-wheel-driving up and down creviced tracks in the Bongolava mountains usually reserved for TV ads for the latest Landrover.
In a landscape gaping with open sores due to rampant deforestation, it takes all the considerable skill of our drivers and an occasional disgorgement of passengers and use of tow-ropes, to get us to our first campsite, high on a mountain ridge.
From here, we trek 17 kilometres across and down the steep escarpment, as porters lug our gear, pausing for a second night's camping on a sandy beach beside a tributary to the Manonbolo River.
This morning, after gathering last minute supplies in Ankavandra, including live ducks and chicken that travel with us in our canoes, we set off on our four-day journey down this little-explored waterway.
The further we go into Western Madagascar, the more traditional and untouched by tourism are the villages and people we encounter.
Along the river, children splash and whoop as we approach, women look up from doing the washing and wave and men, some carrying rifles with which to protect their zebu (cattle), exchange pleasantries with our river guides.
Although the Lonely Planet guide describes Malagasies as "rather reserved", we don't find them shy at all and most we meet appear happy, in spite of or perhaps because of their circumstances. While there may not be starvation here, where freshwater fish like tilapia can be caught, rice can be grown and wild mango trees and banana plants line the river, people have little more than basic huts and clothing.
Our canoe guides, from Ankavandra, are small, wiry and deceptively strong. Dada, 45, who shares the paddling duties on my canoe, is tiny but often jumps out and pushes when we get stuck on a sandbank.
He and I develop a warm rapport, exchanging biographical details and jokes in the French we both learnt at school – Madagascar was a colony of France between 1896 and 1960 and the language is still widely spoken. Dada has five children, I discover, the oldest of whom is 21 and another of our canoe guides and the youngest, "with another wife", is only one. Although he knows the river and the surrounding region intimately, he has never travelled to Antananarivo.
Every afternoon, about now, Dada leads his crew in song, perhaps the Malagasy equivalent of "row, row, row your boat" or begins poking fun at other guides, who return his jibes in spades, to much accompanying chortling. Their good spirits are admirable given that one of our guides was replaced at the last minute because his father, well-known to all the others, was shot dead the day before, downriver. He'd been trying to steal zebu – a common way of accumulating wealth in this area. The body of the deceased is being brought back to Ankavandra as we travel down it.
Our overall guide for this trip is Daffy, full name Fidy Eddy Rakotondranaivodafimiarantsoa, a 29-year-old farmer. He is not only fiercely intelligent and knowledgeable but disarmingly honest about his country. Some guides might hide the shooting from us but he trusts us with the information, which reassures rather than disturbs.
"If you go out in Antananarivo," he tells us on our first night in the capital, "take nothing – no money, no passport, no camera, nothing". This is not an idle warning – after the trip has ended and one of our group, 71-year-old Melburnian Peta Cross, is back in the capital, she is robbed of her handbag, containing iPhone and camera.
But it's a long way to Antananarivo now and little in the low-lying landscape feels threatening, even a 2.5-metre Nile crocodile, spotted on the riverbank, appearing too indolent and well fed to cause a stir.
Apart from cheeky chameleons, we see egrets, ibis, herons and beautiful blue-breasted kingfishers in the riverside vegetation and kites circling above, searching for food. As we progress "mora, mora" or "slowly, slowly" along the wide, brown Manonbolo, in a part of Madagascar that few tourists see, we begin to feel connected to the essence of the island and its largely agrarian way of life.
When our daily paddle stops, around 4pm, we haul our canoes onto a white sandy beach. After helping our guides pitch our tents, we are into relax mode, swimming and washing in the river and gathering for rum and fruit juice and snacks before dinner, served on an upturned canoe.
What Dada and his crew produce, from three small campfires, is remarkable, from French onion soup to grilled fish and roasted zebu or fowl, to plentiful vegetables. We even get pancakes with chocolate sauce for dessert. Lunch, taken in the shade during the hottest part of the day, is also cooked and plentiful.
There is not a single night on the river when I don't sleep straight through, from when my head hits the pillow around 8pm to just before sunrise. Then after coffee, fruit and home-made fried bread we are away.
The first few days, in this late dry season trip when the river is very low, are a bit stop-start as we negotiate sandbanks, but there is usually a cooling breeze and the further we go the easier it gets, with deeper water and the appearance of some arm muscles. The latter stages of our descent are also more dramatic, with broken sandstone walls lining the river and, on our last day, the cliffs of Manonbolo Gorge rearing up on either side.
On our last morning, we paddle a short distance down a creek and then walk into a limestone canyon, at the edge of Tsingy National Park. The scenery here is reminiscent of North Western Australia, with worn, pock-marked boulders, shallow waterfalls and emerald pools. We find two translucent swimming holes fed by cascades and spend the morning cooling off in them.
Back on the river, we move quickly through Manonbolo Gorge, its 100-metre walls hollowed, fractured and layered by the rampaging wet season flow, but slow down when we see our first lemurs of the trip, four white sifakas playing high in trees.
Our canoe trip draws to a close when we reach a permanent camp, near to the tourist village of Bekopaka, where our accommodation is upgraded to bungalows and we wallow in our first hot showers in four days.
But before that, we must say farewell to our trusty river crew, who are heading back to Ankavandra, with speeches and lashings of cold beer.
Having paddled 74 kilometres down the Manonbolo with guide Dada in my canoe, it is only when he and I exchange goodbye hugs that I realise the extent of our size discrepancy. The genial Malagasy, who has done the lion's share of the work, is dwarfed by my 1.86-metre frame and probably half my weight.
South African Airways has daily flights to Madagascar from Australia's East coast, via Perth and Johannesburg, connecting to Antananarivo using SA Airlink. Flights from $2440 return, including taxes. See flysaa.com.au or phone 1300 435972
World Expeditions has a range of journeys exploring Madagascar; the canoe safari is part of the 21-day Madagascar Adventure, from $4690 per person. Phone 1300 720000, see worldexpeditions.com
Daniel Scott was a guest of World Expeditions, South African Airways and Airlink