(CNN) — As the boat lurches over another huge wave, a whale slaps its massive tail, against the water in front.
These mammals make Olympic gymnasts look like amateurs as they acrobatically lift their enormous bodies in gravity-defying displays.
We're traveling across Antongil Bay to the far-flung Masoala Forest Lodge on Masoala peninsula, a vast national park on Madagascar's northeast coast, and the island's last remaining untouched rainforest.
Between July and September, thousands of humpback whales also journey here to calve and mate, during their long migration from Antarctica.
The Masoala peninsula is the largest protected area in Madagascar.
Masoala Forest Lodge
Arriving two hours later we're immediately awestruck by deserted honey gold beaches and spectacular rainforests swarming down mountains.
The thick forest has escaped the deforestation that tragically ravages the rest of this Indian Ocean island.
Masoala Forest Lodge is hidden among this green world, on a never-ending stretch of beach, with not another building in sight.
"I chose here for the wilderness," says the lodge's owner Pierre Bester, a South African, who also run lodges in isolated parts of Mozambique and Malawi.
Maria Bester, Pierre's German wife, is there to greet us as we clamber ashore.
The lodge is an effortless blend of rustic and luxury, with a dining hall resembling a long house and seven palm-thatched treehouses, raised on stilted wooden platforms, standing right on the beach.
During breakfast the following morning we're treated to the sight of dolphins swimming past.
Almost 80 per cent of the species on the island can not be found anywhere else in the world.
Masoala Forest Lodge
A lot of Masoala's wildlife is endemic: strange nocturnal Aye-aye, vibrant Helmet vanga birds and Madagascar serpent eagles among them.
Cut off from mainland Africa 160 million years ago, Madagascar has some of the world's rarest and most unusual flora and fauna.
The forest is a throng of giant buttress roots and towering rosewoods, Ramy and Madagascar dragon trees.
Vines and lianas twist everywhere, headstrong streams rush over rocks and epiphytes glow in the sun.
We're looking for red-ruffed lemurs and find a group of them almost immediately, leaping through the trees, resembling dramatic fireballs with their magnificent crimson fur.
Back on the beach we snorkel among shockingly bright fish.
Masoala National Park became a World Heritage Site in 2007.
Masoala Forest Lodge
"Often we hear whales singing," says Seraphin, our guide. "Female humpback whales choose their mate by their singing skills. Their song is one of the animal kingdom's most complex."
The following day we travel by boat to a pristine arc of beach, hemmed in by rainforest, where hidden coves stretch far into the distance.
From here we travel by traditional pirogue boat up the Antalavia River to a giant pool of cascades in a natural rainforest amphitheater. Pygmy kingfishers and parrots swoop past as we splash about.
The coastal path back skirts the forest. We have the whole place to ourselves, except for a man wandering across the sand with his cows; and a family returning from their tanety (hillside farm), with homemade shrimp traps and baskets of cassava leaves.
Kayaks are available to explore the sculpted granite monoliths that seem to have been flung across the sea.
"Lichen eats the rocks here, eroding them into these dramatic shapes which rear from the water," Pierre explains.
Orchids are more abundant here than any other African forest; enormous clumps elegantly shroud the trees. The most famous orchid is vanilla. Indeed, most of the world's vanilla is cultivated around Masoala. However, it doesn't grow naturally here -- it's in fact native to Mexico.
"The French brought it over," says Seraphin. "The bees which pollinate the flowers do not live in Madagascar so each flower has to be hand-pollinated, making it extremely labour-intensive."
In 2018 Pierre and Maria opened two new private villas: one on Cap Masaola, a secluded point on the peninsula, and the other on a private palm-covered island with white beaches just off it.
Both can be reached by kayak through the tranquil, turquoise Cap Masaola lagoon.
This is real Robinson Crusoe (in luxury); the area is totally unvisited by tourists because it's so hard to get to.
Pierre, however, has been kayaking here -- it's how he first found this area -- since 1998.
Our final week is spent on Ile St Marie, a small island -- just 63 by six kilometers -- off Madagascar's northeast coast.
Houses are stilted and thatched with big verandas and most restaurant names are the owner's family name preceded by Chez (French for "at home") -- because they are just that. You sit on someone's veranda eating a delicious home-cooked meal of zebu or chicken in a creamy vanilla sauce.
Humpback whales migrate from from Antarctica to Antongil Bay between July and September.
Masoala Forest Lodge
We are staying at Princesse Bora, a hotel with a long infinity pool by the sea. The owner, Fifou Mayer, passionate about whales, is one of the founders of Cétamada, an association which protects Madagascar's marine life, and guests are even allowed to go out in its research boats.
The island is perfect for exploring by bicycle and the hotel have some available for guests.
We cruise along quiet lanes, stopping at a crumbling pirate cemetery, dating back to when the island's bays were busy hideouts for pirates (it's close to the East Indies trade route) and a quaint Catholic church, which is Madagascar's oldest.
One day we hire quad bikes and head off to the wild east coast, along dirt tracks, past remote little villages.
We continue our exploration by pirogue through mangroves and wander along beaches, where palm trees lean so far over they appear to be doing press ups into the sea. We swim in the island's lagoon, and visit Ile aux Nattes, a tiny neighboring island, even more isolated than Ile St Marie (and reached by another quick five-minute pirogue ride).
Back at the hotel, Fifou tells us that Malagasy people keep the northeast corner of their homes for their ancestors, so it's a special place.
It seems entirely appropriate that we have spent all our time in Madagascar's northeast, surely the most special area on this island.