Alex Robinson goes in search of the elusive jaguars that live in the Corcovado rainforest, Costa Rica

The Corcovado rainforest is eerily quiet. But for the buzz of cicadas that crescendos past like a wave every few minutes, it’s as silent as a cathedral. I can hear drops falling onto leaves, the burr of a hummingbird’s wings. Then a roar cracks the spell – deep and guttural, huge in the empty air. And my heart leaps into my throat. Adrenaline floods my veins. My hands shake. A panicked blur of thoughts rush into my mind. "It’s a jaguar. My God. And it’s close. Which way’s the wind blowing?"

Before arriving in Costa Rica I’d thought of jaguars as innocuous creatures. A kind of languorous leopard, spending most of its life draped across a log, bleary-eyed and half-asleep. But then I went to San José zoo and saw one in the flesh. Its paws rippled with as much muscle as a heavyweight boxer and its head was as big as mine. It looked at me with great green eyes, filled with contempt. ‘Just let me out,’ they goaded, ‘and we’ll see who’s the dominant species.’ Then it yawned and licked vast, razor sharp chops. ‘Jaguars’, said the plaque, next to the cage, ‘have the strongest bite of any big cat. They can crack a skull like an egg.’

And now one’s downwind of me. It can smell my fear. I lurch into action and run up the path, splashing through the mud, camera swinging madly, and nearly collide with Juan, the Lapa Rios eco-lodge guide. He’s looking through binoculars up into the trees with all the panic of a meditating monk.

Alex Robinson, Guide from Lapa Rios in the Osa Peninsula, Costa Rica, Central AmericaImage by Alex Robinson

"You OK?" he asks, startled by my muddy appearance. "Jaguar!" I yelp, "Didn’t you hear it roar?" For a moment, he’s puzzled. Then his face splits into a grin. "No jaguar amigo! Ees a howler monkey."

He points up into the canopy and hands me the binoculars, elegantly shifting the mood away from my flustered embarrassment. And I see the monkeys – a family of harmless-looking, Bournville-brown things, about the size of spaniels. They’re chewing leaves. "They made the roar?" I ask.

On the way back to Lapa Rios, Juan explains. Male howlers have a bark far worse than their bite. According to Juan, humans could learn a lot from them. Imagine, he says, if all we had to do to defend our territory was to gather battalions together at our borders and collectively yell at each other. Most howler battles amount only to this. They do come to blows, but only very, very rarely.

Alex Robinson, Osa Peninsula, Costa RicaImage by Alex Robinson

As day drifts into twilight, the forest seems peaceful again. A brilliant blue morpho butterfly with wings as big as my hands floats past. The trees clear and I can see the white crests of waves splashing on the sand far below and the silhouetted shapes of swaying coconut palms. All is calm and beautiful and I muse on how privileged I am to be here – a little dot on the Osa peninsula, a thumb-shaped wedge of rainforest fringed on all sides by magnificent beaches and so remote it's easier to fly here. The Osa is one of the last great islands of biodiversity in Central America and a success story for ecotourism. The region depends on lodges like Lapa Rios – my tourist money funds a local school, recycling programmes for lodge itself and the beaches and gives people like Juan a job. Juan is a guide. But his father was a hunter.

We reach the lodge as bats fill the air, whirring past as they chase insects. Coatis chatter in the bushes and a startled nightjar whips up from the path in front of us, swirling and swooping into the night. The dining room is a warm orange glow under the palm-thatch, the path to the rooms – which are perched on wooden stilts overlooking the Pacific – is lit with soft-white fairy lights. I’ve only been away on my hike for a few hours, but I feel like an intrepid explorer on a long awaited homecoming.

I shower, eat a delicious meal of lemon-marinated sea bream, washed down with ice-cold Argentinean Sauvignon Blanc and drift off to the music of the forest. There are jaguars out there somewhere. Thank God. Still thriving in this remote and beautiful corner of Costa Rica. I’m not sure if I’m happy or sad that seeing them is so hard. Tomorrow will be another sparkling bright sunny day, and a new adventure. I’ll be learning to surf those creamy Pacific waves. And hoping I don’t embarrass myself again - with fears about imaginary sharks.

Follow Alex Robinson on his website and on Alex Robinson Photographer. The Osa Peninsula can be visited with Journey Latin America on their Costa Rica Wildlife Holiday. Explore more of Costa Rica with the Rough Guide to Costa Rica. Book hostels for your trip, and don't forget to purchase travel insurance before you go.