May 14, 2024 • Travel Ideas
In spite of its small size (roughly that of West Virginia or Denmark), Costa Rica is home to nearly half a million species, making it one of the most biodiverse countries on earth. And within Costa Rica, there is one place that stands above the rest when it comes to biodiversity: the Osa Peninsula. Covering an area of just 700 square miles along the Pacific coast, the Osa Peninsula hosts half of Costa Rica’s animal and plant species among its spectacular rainforests while covering only 3 percent of the country’s land area. National Geographic went so far as to call the Osa Peninsula the most “biologically intense place on earth.”

The Osa Peninsula is coated in thick rainforests and winding rivers, home to near countless Costa Rican rainforest animals. © Brian Hutchinson
A trip to Costa Rica’s Osa Peninsula offers a guarantee for close encounters with a remarkable number of Costa Rica’s rainforest animals. The peninsula is renowned as a thriving bastion for all four of Costa Rica’s monkey species, tropical birds like the Scarlet Macaw, sloths, neon-colored frogs, and even sea turtles that come ashore to nest on the jungle-clad coastline.
Sloths

A two-toed sloth hanging among the canopy in a Costa Rica rainforest. © Koen Swiers
Sloths are perhaps the most famous Costa Rican rainforest animals, and Costa Rica may be the best place in the world to find them hanging sleepily from the treetops. Two sloth species make the Osa Peninsula their home: the two-toed sloth and the three-toed sloth. Both are famously slow (their Spanish name, perezoso, literally means “lazy”), survive mainly on tree leaves, spend nearly their entire lives dangling in trees, and are surprisingly good swimmers. Today, the three-toed sloth is about the size of a house cat, but their ancestors were once the size of elephants. While sloths can be very difficult to spot in the rainforest, nature guides are exceptionally good at finding them. One common method is to look for Cecropia trees, a conspicuous genre of tree that is found in pastures and secondary forest areas and is favored by sloths.
Coatis
This adorable animal is a coati. Like raccoons, coatis are highly intelligent. © Brian Hutchinson
Coatis are a bit of a mashup of a critter, perhaps described as miniature raccoon with the face of a fox and a long feline tail. Whatever the description, they are exceedingly cute. Wild coati roam during the daylight and commonly wrestle with each other like playful dogs, and even hunt snakes. They are easy to find on the Osa Peninsula, particularly in cleared areas, like on the grounds of your lodge. Fun fact: when watched in reverse, coatis look like miniature dinosaurs.
A canopy walk is perfect for spotting Costa Rica rainforest animals, like birds, monkeys, and countless others. © Brian Hutchinson
Macaws & Toucans
With thick jungle covering much of the Osa Peninsula, it is unsurprisingly a birder’s paradise. Staying at a rainforest lodge and hiking through canopy trails provides travelers ample opportunity to spot some of the nearly 500 species of birds that can be found on the peninsula. Notably, the Osa Peninsula is the best place in Costa Rica (and among the best in the world) to see Scarlet Macaws.
Scarlet Macaws can be readily seen on Costa Rica’s Osa Peninsula. These colorful and charismatic birds mate for life. © Brian Hutchinson
The Scarlet Macaw is the largest of the parrot family and one of the most beautiful Costa Rica rainforest animals. Thanks to their large size, vibrant plumage, and raucous squawks they are hard to miss.
Big, colorful, and boisterous, Chestnut-mandibled Toucans are a delight to watch. © Brian Hutchinson
You may not need to work hard to spot the Chestnut-mandibled (aka Yellow-throated) Toucan, which is known to make appearances around the gardens of hotels. These banana-loving birds tend to travel with their mate during breeding seasons and are most famous for their bright, beautiful yellow and maroon bills, gentle caws, and neon plumage.
Monkeys
Living among the cloud forests, dry forests, and rainforests of Costa Rica are four iconic species of monkey, and all of them can be seen on the Osa Peninsula: the golden-mantled howler monkey, Central American squirrel monkey, Geoffroy’s spider monkey, and the white-faced capuchin monkey.

Howler monkeys are often seen (and heard) in the dry forest, living in large family groups. © Brian Hutchinson
The mantled howler monkey’s guttural call can be heard 3-miles away and is unmistakable above the jungle drone. Listening to their chants while lying in bed at an ecolodge or sipping coffee on a patio will quickly remind travelers of the wild that surrounds them.
A playful and inquisitive Squirrel Monkey. © Brian Hutchinson
The squirrel monkey is the smallest of the four monkey species in Costa Rica, only slightly larger than an actual squirrel. These charismatic and playful animals tend to travel in troops of 20-75 individuals, and are often seen by the dozens moving through the rainforest.

A spider monkey mother and baby on the Osa Peninsula. © Brian Hutchinson
Geoffroy’s spider monkeys are famous for their spindly limbs and long, muscular tails which can easily grasp branches, which along with their hands allow them to swing through the forest with grace. Due to habitat loss, the Osa Peninsula now offers one of the last and best bastions in the world to view this iconic species.

A white-faced capuchin monkey in the Costa Rican rainforest. © Andre Vujovic
The white-faced capuchin monkey is the most common of the four species in Costa Rica and can be readily seen on the Osa Peninsula. Not only are they famously curious, they are infamous for stealing unsuspecting tourists’ food. But that doesn’t mean tourists should feed them, in fact it is illegal. Doing so can harm their health, disrupt their natural diet, and cloud their survival instincts. Because the Osa Peninsula is largely wild and has relatively few tourists, white-faced capuchins are more likely to keep to themselves and behave naturally in their rainforest home.
Sea Turtles
The rainforest meets the sea on the Osa Peninsula. © Brian Hutchinson
Although it may seem odd to call sea turtles a Costa Rica rainforest animal, it’s hard to deny the connection between the rainforests of Osa Peninsula and the olive ridley sea turtles that come ashore to nest on wild beaches where the rainforest meets the sea. In fact, the Osa Peninsula is one of the few places on earth where jaguars (the rainforest’s top predator) are known to feast on nesting sea turtles.

A newly hatched olive ridley sea turtle at Ostional. © Brian Hutchinson
Remarkably, sea turtles nest on the same beaches they were born. Those that live to adulthood will sometimes travel thousands of miles across the oceans over decades before returning to their birthplace to give birth to the next generation. With a little planning and the right itinerary, travelers to the Osa Peninsula can see newly hatched olive ridleys take their first steps as they make their way to the ocean.
Frogs

A green and black poison dart frog on the Osa Peninsula. © Brian Hutchinson
Roughly 150 species of frogs are found in Costa Rica, including brightly colored poison dart frogs that stand out like jewels among the rainforest floor. Their neon patterns warn predators to keep away, as toxins on their skin can make them fatal to consume. The Osa Peninsula is a great place to look for poison dart frogs, red-eyed tree frogs, glass frogs, and other iconic amphibians of Costa Rica.
Tour the Osa Peninsula with Oceanic Society
These are just a few of the many wonderful rainforest animals that can be seen during a tour of the Osa Peninsula, which we consider a must as part of any Costa Rica eco tour itinerary.
Listen to the sounds of the jungle while perched on a cliff overlooking the Pacific, at the Bosque del Cabo hotel, Osa Peninsula. © Brian Hutchinson
Oceanic Society has been pioneering sustainable and ethical wildlife expeditions to the most biodiverse corners of the world for the last 40+ years. Our adventures immerse travelers in the most vibrant ecosystems while also supporting the economies and ecosystems we visit through our unique sustainable travel model. Each booking of a tour supports our nonprofit conservation work around the world as well as directly sponsors the removal of 200 pounds of ocean pollution.
Join us on an upcoming Costa Rica eco tour and you can not only experience the amazing wildlife of the Osa Peninsula up close, but do so in an ethical way that contributes to nature conservation in Costa Rica and worldwide.
