"Shh!" Zakamisy, our guide, has spotted something. "Panther chameleon! Male!" A prehistoric-looking green lizard with a coiled-up tail clings to a branch. Long before the first human settlers arrived from Indonesia 2,000 years ago, this land belonged to its wildlife. Now only 20% of Madagascar's forests remain. Two and a half times the size of Great Britain, Madagascar is the fourth largest island in the world. It's neither Africa nor Asia but something in between, with 18 distinct ethnic groups sharing one language and a fascinating culture. There are tropical rainforests, dry deciduous forests, rocky canyons and glorious, deserted beaches. And creatures innumerable: wherever you go, a pair of beady eyes is watching.

From Anjajavy, we go by boat to a sacred baobab tree, mushroom-shaped islands and mysterious ancestral resting places. We walk through virgin forest among huge land crabs. At sunset, we sip cocktails and watch ethereal flying foxes circling between the dark green mangroves and the white moon. The hotel owns a swathe of forest along this coast, which ensures its protection from the deforestation devastating the rest of the island.

Just offshore, Nosy Tsarabanjina is a hippie-chic resort, 20 beach huts on a minute, perfect island with the whitest sand and an intact coral reef. We followed a turtle and swam with shoals of brightly coloured fish before walking round the rocks to a fish supper in the sand-floored bar.

Madagascar was a French colony for more than 60 years. In Joffreville in the mountainous north, the charming Domaine de Fontenay, a former consulate, boasts vast grounds, a giant land tortoise and a fireplace designed by Gustav Eiffel. It's a few hours from Diégo Suarez, a northern port town, poor but smart thanks to the president's drive for civic pride. Diego is at the head of a vast bay with a sugar-loaf mountain, home to ancestral spirits, hence out of bounds — fady — to the living. Montagne d'Ambre is the place for full-on rainforest: tree ferns, bird's-nest ferns, green volcanic lakes, waterfalls and, of course, more varieties of lemur. At night the forest was full of the eerie whistles of frogs. We picnicked on zebu kebabs and wondered at the smallest chameleon in the world, under 2 centimetres long.

We marvelled at the Tsingy Rouge, an enormous ravine of sharp, ancient rock formations unique to Madagascar. We arrived at the imposing limestone massif of Ankarana, caked in red dust but impressed by Zakamisy's ability to keep the 4x4 on the rocky road and simultaneously spot flora and fauna and tell us jokes and folk tales. We hiked through huge caverns to lost forests, all very Indiana Jones, then cooled off in a natural pool and headed back to camp for delicious chicken and coconut stew.

Kathy Brewis travelled with Rainbow Tours, 020 7226 1004. A similar 12-day trip costs from £2,595 per person including flights.