How to stay in a Costa Rican jungle overnight—and live to tell the tale

Mornings in Corcovado National Park do not break gently — instead, they start with a roar. For a moment, it feels like there are monsters afoot, their shrieks rolling through the forest in waves, engulfing every knotted vine and thick-rooted fig tree. But my guide, Maria Castro, assures me this a natural way to start the day. She squints through shafts of sunlight and points in the direction of shaking leaves, where I catch a glimpse of elongated, hairy limbs. Then a pair of round faces stare down, their mouths agape, eyebrows raised: not monsters — howler monkeys.

“They howl to communicate danger between groups,” explains Maria. “It helps keep them safer from predators. You can hear them from three kilometres away.” I look around, wondering what else might be lurking nearby. The answer is a lot. Within half an hour of arriving in Corcovado for a day tour and overnight stay, it’s abundantly clear that this reserve in southern Costa Rica’s Osa Peninsula, on the Pacific coast, is living up to its reputation as one of the most biodiverse places on the planet.

Bull sharks crest the waves that bash against the park’s shores and crocodiles and caimans infest its rivers, while shaggy anteaters snooze amid the branches of tall fig trees. Corcovado is home to jaguars and pumas, and is also the best place in the country to see tapirs ­— a cow-like creature with an elephant-like trunk, averaging two metres in length and weighing up to 270kg.

And then there are the monkeys. “They’re like dogs on branches,” says Maria, as the howlers climb down on all fours to take a closer look at us. They’re joined by auburn-haired spider monkeys — “my favourite” says Maria, with a grin. “These are the most acrobatic monkey we have here. They have strong tails to grip with.”

Maria talks about the animal world like it’s part of her extended family. “I really love this place. My mum was also a guide and she brought me here — I’ve been coming to Corcovado since I was nine,” she explains as we continue along a forest path. “When I was a child, I would spend a lot of time playing with mimosa plants,” she adds, crouching down and prodding a delicate, feathery leaf that curls protectively at her touch.

Everything here feels alive. Armies of red ants form rivulets at our feet; rat-like agoutis follow plump, crested guan birds through the undergrowth; and the cicadas crescendo again and again, making it feel like the jungle itself is breathing in and out. Yet, in a way, it’s also quiet. The number of visitors to this 162sq mile park is strictly controlled through permits. Only around 250 people are allowed to enter per day — and less than half of those, like me, will be booked to stay overnight at one of the park’s ranger stations. “Visitors can only see 2.5% of Corcovado. The main thing here is conservation,” says Maria, as our path emerges into an abnormally large clearing of tall grasses. At one end is the Sirena ranger station; at the other, the sea.

We’re standing on Corcovado’s disused airstrip. “Before 1975, Sirena was a big farm,” explains Maria. Up to 300 families lived in this area. They cleared primary forest for farming, while the rivers fell victim to illicit gold-panning. But all this stopped when the farming land was reclaimed to establish the national park in 1975. The secondary forest that’s since grown produces an abundance of fruits and mushrooms that attract wildlife. Now, the national park is one of Costa Rica’s greatest conservation success stories.

At its heart is the Sirena ranger station: a neat quadrant of wooden buildings with open sides, housing a canteen, quarters for the handful of rangers who live here and a huge dorm of mosquito-netted bunk beds. It’s here I deposit my overnight bag before settling into a wooden chair on the verandah with a steaming mug of black coffee, watching tiny yellow great kiskadee birds hop on a radio antenna. Around me, guides are chatting about the animals they’ve already spotted en route to the station.

“Sirena means mermaid in Spanish,” says Maria later that day as we sit on a log beside the Sirena River, at the mouth to the sea. Our booted toes sink into the sand that lines the riverbank, which trickles into a beach backed by palm trees. The five-metre-long crocodile that’s just grabbed a heron has put paid to any notion I might have had that it feels like sunbathing territory. As we watch it shake the bird’s body in its jaws, Maria continues to tell the river’s story. “There was a farmer’s daughter who used to cross the river, swimming, and one day she didn’t come home. She was probably eaten by a crocodile like this one, but local people said she became a mermaid.”

A mythical creature is exactly what I feel like I’ve encountered later, when a tapir lopes onto the beach. It’s dusk, and as all the day-trippers left after lunch, just a fraction of this morning’s hikers remain in the park. I sink cross-legged in the sand to watch the creature trace the treeline, pulling off large leaves. Its rotund body looks oversized, its stumpy, trunk-like mouth too large for its jaw. By the time we make it back through the dark jungle to the ranger station for dinner, this encounter is all any of the overnighters are talking about. We eat heaped plates of rice, beans and plantains at rickety tables in an open-air dining hall, the drone of cicadas merging with our chatter.

The floors creak as we shuffle off to our bunkbeds. Lights go out at 8pm sharp, but it never truly feels like the jungle sleeps. Insects croak, twigs snap, leaves rustle. I imagine the pumas that could be slinking through the undergrowth, and I sleep in fits and starts. By the time shafts of light are warming the ranger station, I’m sipping coffee with Maria on the porch. It’s just before 5am when I hear the now-familiar sound of roars in the jungle. The monsters are back; it’s time for the day to begin.