Capuchin monkeys are cavorting through the trees, while an agouti shoots out of the undergrowth and trots briskly across our path, for all the world like a guinea pig with extra-long legs. A coatimundi - a kind of oversized racoon - snuffles in the bush, while spiny-tailed iguanas bask on branches.
The Curu Wildlife Refuge, on the Nicoya Peninsula, offers instant immersion into the humidity, the dense rainforest and the abundant fauna of Costa Rica. As we scramble over roots and try to dodge processions of leaf-cutter ants, I'm getting a rapid tutorial from our guide, Erika, on the concept of pura vida, Costa Rica's most popular saying. 'It's literally translated as "pure life",' she says. 'But it also means "hello", "goodbye" and
"everything's fabulous" -whether you really mean that or whether you're being sarcastic.'