In some parts of the world, there literally isn’t any space between the black sand beach, waves battered by the cool Pacific, and the herbaceous riot of lowland rainforests rolling tangled, damp, and exuberant down the zigzag mountains.

In fact, there aren’t many places left where unspoiled tropical jungle throws leafy shadows on a beach crisscrossed by heavy loops of sea turtle imprints and jaguar tracks.

And right at that moment, the proximity of the forest to the beach crystalized. I had surprised a Baird’s Tapir, six feet long and nearly four feet tall, supporting up to 800 pounds. It is the largest land mammal found in Central America.

Apparently the animal had bedded down to wait out the afternoon heat, while I had continued hiking in sweat-soaked clothes, gulping tepid water every few minutes. What, at first, looked like a peculiar rock, suddenly stood up on large hoofed feet, twisting its proboscis this way and that.

I stood nailed to the spot between the tapir and the dense undergrowth the species prefers for escape. Neither of us quite knew what to do.

After a few moments, the animal crashed through a tangle out onto the beach and stomped out of sight.

Into the wild

While wildlife and rainforests are disappearing from many places in Central America, the trend may be reversed in Costa Rica. The Osa Peninsula in the remote southwest corner of the country still supports swaths of rainforests and encounters with some of the jungle's mega fauna are still possible.

However, if you prefer not to make eye contact with a wild jaguar, there is plenty of smaller plant and animal life to marvel at. The lowland rainforest found on the peninsula is some of the best preserved of its kind in the world, and harbors some of the highest biodiversity on earth.

But it isn't numbers that make a lasting impression on the visitor. It's the sheer fecundity of the place that comes alive every morning with hundreds of strange calls, a plethora of colors and the rush of hundreds of rivulets, creeks, and streams.

Mind the flora and the fauna

Climbing one of the steep ridges, I passed the gargantuan buttressed trunks of 100 year old trees, scientifically known as emergent trees. Their trunks piercing layers of dark green and vanished out of sight.

Far above, I could hear the chatter of endangered squirrel monkeys. These pint-sized primates usually travel in large groups and cause quite a racket.

It is often hard to enjoy sweeping views in intact rainforest, but after a few more minutes, I reached a small promontory near the edge of the Corcovado National Park. The boundary was invisible in the untouched forest.

As the forest exhaled, clusters of cloud drifted from the valley below. Far across, howler monkeys let other groups know that part of the forest was taken. Past undulating green, the distant blue of the Golfo Dulce, a deep tropical fjord and home to humpback whales, was visible.

Play a little Frogger

Smaller than a thumb, but potentially lethal, poison dart frogs are one of nature’s chemical wonders. Unlike most frogs, which are nocturnal and camouflaged to avoid being chomped on, poison dart frogs appear brazen. They sport flashy colors ranging from bright red, shiny black and green, to blue and orange, hopping along open trails during the middle of the day.

Even though they are comparably visible amphibians, it does require some effort to spot one in the wild. The best time to look for one is after rain, which occurs nearly every day during the wet season lasting from late April through December, but downpours occur any time of year.

Poison dart frogs like deep leaf litter and can often be found along small streams in deep ravines. The Osa Peninsula harbors several species ranging from screaming red through black with orange lines.

Go take a hike

Corcovado National Park encompasses approximately one-third of the peninsula and offers a limited trail system. Hikers can tackle the long section from Los Patos ranger station to La Sirena ranger station in the heart of the park, and then follow the coastline south toward La Leona ranger station and the small town of Carate. This trip involves at least one night camping at La Sirena.

Another great option to cross the rugged peninsula on foot is an all-day walk from the small village of Dos Brazos on the Rio Tigre towards Carate. This “trail” should only be attempted with an experienced local guide.

My guide, Ulysses, and I started upstream in the early morning, with the cool night air still clinging to the valley. By the time we left the stream to turn onto a muddy path snaking its way up a steep ridge, the sun and humidity had already thickened the air.

A slippery, root-clenching few minutes later, we followed a wide path along a flat ridgetop through primary forest. High up in the canopy, a single spider monkey held its ground, visibly dissatisfied by our intrusion.

Near the center of the peninsula, we passed the small gold mining camp of Piedras Blancas, where a handful of people and two dozen scraggly mutts carve out a meager living.

Deeper into the forest, tapir and jaguar footprints overlapped along a muddy river bank.

What goes up, must come down, and down we came a steep narrow trail towards Carate and the Pacific Ocean, past several small waterfalls beckoning with cool water.

Take a swim

The heat in the Osa Peninsula can be relentless, and the best thing to do during the midday peak is to find a waterhole or cascade along one of the many streams.

The water tumbles clear and refreshing from the mountainous interior, where some summits reach up to 3,000 feet. While soaking tired feet, the lucky may even spot one of the rare Central American river otters that still frequent the creeks.

Make a frontier pit stop

Puerto Jimenez is the largest town on the peninsula and the transportation hub. The airstrip is located here, and buses rumble along the dusty dirt road to the main station.

Hotels in town are usually a ramshackle affair, but lodging can be found in every amount, ranging from jungle camping to high-end resorts just outside town. However, there are no hotel strips, and most places still offer 360-degree rainforest views.

You can also organize tours into Corcovado National Park and rent necessary expedition gear. And after a jungle trek, there are enough pizza joints and Internet cafes to reconnect seamlessly with civilization.

Lend a helping hand

While much of the rainforest here is protected, the region still suffers from many environmental problems common throughout the tropics.

Volunteers can help with a large variety of projects. Scientists and conservationists are active throughout the Osa Peninsula in order to protect the unique flora and fauna.

The non-profit organization Friends of the Osa seeks to purchase and conserve land and has one of the best established volunteer programs in the region.