Costa Rica is a small country in Central America bordering Nicaragua to the North and Panama to the South. It is home to 5% of the planet’s biodiversity ! Out of two million species identified in the world today, about 91,000 are found in Costa Rica. In other words, nearly one species out of twenty known in the world lives in Costa Rica. Biologists discover 160 new species every year, in Costa Rica, one every two days… All this life is concentrated in national parks (the two oldest were created in 1955), biological reserves, and wildlife refuges covering a quarter of the territory. Whether you go for a boat ride or walk on the suspended bridges in the canopy, wildlife is all around you: it is an incredible Noah’s Ark! But, for the envious and impatient neophyte, the fauna sometimes remains invisible… the paradox of the tropical forest !
A peccary is a medium-sized pig-like hoofed mammal with greyish-brown fur. The peccary lives in large family groups in the tropical forests of Costa Rica.

The peccary


The mutualism of the Costa Rica fauna and flora: Art of sharing !

Fifteen thousand species of butterflies, 922 species of birds, 230 species of mammals, 220 species of reptiles, 190 species of amphibians, 34,000 species of insects, 1,600 species of fish, and 10,000 species of plants: few countries can compete with the biodiversity of Costa Rica! Immersing ourselves in the natural reserves to observe the fauna and flora is one of the main leitmotivs of our stunning escape to Costa Rica. The tropical forest has a density of species per hectare unique in the world. All animal encounters are possible along the forest trails if you remain silent, look everywhere, and are attentive to the slightest crackling, buzzing, or whistling… And above all, keep in mind that the forest does not offer only large mammals. It is also home to insects, brightly colored dendrobates, Anolis, or birds with colorful plumage. It is not necessary to walk for miles along the trail to see them…

The Resplendent Quetzal male has bright iridescent blue-green upperparts, throat and upper breast, but the color differs according to the light. Its throat and abdomen are red.

The Resplendent Quetzal male

The first question that comes to mind is, « how can so many animal species coexist in tropical forests ? » The forest canopy offers many sources of food, shelter, and refuge for animals. There is much water and a more or less constant temperature, which allows for the development of luxuriant vegetation, a true paradise for herbivores… and in turn, a rich table of delicious food for predators. We have been taught that botany and zoology are two distinct subjects. Even today, Universities have separate departments for botany and zoology, and each subject has its own scientific journals… However, in tropical forests, fauna and flora are intimately linked and practice the art of sharing or mutualism.

« Unshared pleasure is only half pleasure ». (French proverb)

There are many examples of mutualism (relationships involving mutual benefits) in rainforests, such as frogs that use the water reserves stored in the leaves of bromeliads to hunt and lay their eggs. Animal species provide vital services to forest ecosystems. The seeds of some plant species must pass through the digestive tract of herbivorous mammals or birds before they can germinate. The Peccary has one of the most robust jaws of any herbivorous mammal, which allows it to break the tough seeds of palms. The smallest seeds are swallowed intact and excreted a few hours or even days later, still viable, ready to germinate. We could also mention the mythical Quetzal, prince of the cloud forests, who loves wild avocados (or aguacatillo). It swallows them whole and spits out the pit, which will potentially give a new avocado tree! By the way, the Quetzal is also known as « tepeaguacate » because of its fondness for avocados.
Scorpions can lie in ambush under bark in the costa Rican tropical forest. Costa Rica has scorpion species that qualifies as non-lethal.

Scorpion can lie in ambush under bark


Observing wildlife in Costa Rica: Watch out of dangerous species !

Many forest trails, more or less developed and maintained depending on the place, allow us to observe Costa Rica’s fantastic fauna. If I dared to compare, I would say that these hiking trails are a bit like a ski slope: you take great pleasure by walking on them, but you expose yourself to danger by stepping away from them. Keep in mind some ants have painful bites, stinging caterpillars (like this Automeris moth caterpillar) are highly irritating to the skin and cause severe rashes. Scorpions can lie in ambush under dead leaves or bark, and despite their cheerful looks, amphibians can secrete very harmful poisons. Costa Rica has more than 190 species of amphibians, of which 33 are endemic. These 190 species of amphibians represent 3% of the world’s biodiversity !

The Strawberry Poison-dart Frog, also called the Blue-jeans Frog, has brilliant red head and back and blue-to-purple legs comprise a coloration distinct from all other frogs !

The Blue Jeans Frog

Amphibians and insects

It is well-known that in fairy tales princesses will kiss a frog to turn it into prince charming. While Costa Rican frogs of the dendrobatidae family are often very colorful and attractive, such as the blue jeans frog (Oophaga pumilio), we remind our informed audience that inappropriate handling, including kissing, can result in severe trauma, rather than the appearance of young Prince Naveen of Maldonia (see “The Princess and the Frog”). The Green-and-Black poison dart frog (Dendrobates auratus), recognizable by its mint-green coloration mixed with black splotches, is highly toxic. A small quantity of batrachotoxin (a cardio and neurotoxic steroidal alkaloid) secreted via glands in its skin is a poisonous alkaloid. This toxic substance is so powerful that it dissuades most of its predators, except for some spiders. The Green-and-Black dart frogs, also known as « Green poison frog » and « Poison arrow frog », among others, is so called because its toxins are used by some Amazonian tribes to coat their arrows when they go hunting with a bow or a blowpipe.

The Green and Black poison dart frog gets its common name from its coloration, a black background with a green pattern. The bright color of the Green and Black poison dart frog warns predators of danger

The Green and Black poison dart frog

When exploring the rainforest, be careful where you step and put your hands! For example, do not inadvertently touch a colony of Paraponera clavata, commonly known as « Bullet ants ». This species is one of the largest species of ants, measuring between 0.7 and 1.2 inches.  In Costa Rica, Paraponera clavata is known as « Bala », meaning bullet. The ant is named for the severe pain that follows a sting. Some unlucky victim compared the paint to that of being shot. The Bullet ants’ sting is the highest on Schmidt Sting Pain Index. Poneratoxin, a paralyzing neurotoxic peptide isolated from the venom, affects nerve cell function, causing pain and paralysis that can last between 12 and 24 hours. Thus, in Venezuela, the ants are called « hormiga veinticuatro », the « 24-hour ant ». Smaller and less painful ants of the genus Crematogaster, also known as acrobat ants, live in symbiosis with Collins’ acacias. They are characterized by a distinctive heart-shaped abdomen (gaster,) which gives them also the name of Saint Valentine ants. In exchange for room and food, they ardently defend the place. So, brushing up against an acacia a little too closely could leave you with an unpleasant pain for a few hours… In conclusion, the less you touch the vegetation, the less you risk this kind of incident.

The parrot snake is essentially green with gold and bronze and on the dorsal surface scales has a black edge.

The parrot snake

The snakes

If the first part of this story is not spine-chilling enough, then let us move on to the cold-blooded reptiles… Snakes are to be taken seriously, even if very few of the 160 or so species in Costa Rica are poisonous. The Colubrids are the most common snakes. They are harmless and not venomous. It is difficult to recognize them, but their main characteristic is the absence of fangs on the upper jaw. Leptophis ahaetulla, also known as Lora or Parrot snake is of the same Colubridæ family. Diurnal and perfectly adapted to arboreal life, the Parrot snake evolves with incredible speed in the tropical vegetation. Its back is bright leaf green, and it has two thin lateral stripes. The Parrot snake specializes in bluffing: to frighten us, it opens its mouth wide pretending to attack. Without venomous fangs, this intimidating position is its only means of defense. And very often, it works… Have confidence… and trust in me !

« Are you alone out here? What are you doing so deep in the jungle? Don’t you know what you are?… I know what you are. I know where you came from. Poor, sweet little cub. I’ll keep you close. Let go of your fear now… and trust in me… »
(Kaa –The Jungle Book)

Instead, we should rather be wary of small, relatively calm snakes perched on a branch or camouflaged under a leaf. These should not be disturbed ! The Schlegel pit viper, also known as Eyelash Viper (Botriechis schlegelii), is a small species of pit viper ranging from 20 to 32 inches in length. The Eyelash Viper has an extensive range of colors, including red, green, yellow, and brown. In the wild, this venomous snake adopts mainly a green color with shades of brown to aid in camouflage in the rainforest. It is nocturnal, feeding on small rodents, frogs, bats, lizards, or small birds which it attacks by ambush at dusk. The Eyelash Viper is not known to be an aggressive snake and strikes only if disturbed. It is better to wary of its particularly dangerous venom… especially in young ones. The juvenile vipers are born with fangs and venom glands already operational. Being less experienced than their elders, young vipers will tend to release the full dose of venom in one bite.

Mowgli : « You told me a lie, Kaa. You said I could trust you. »
Kaa : « 
It’s like you said. You can’t trust anyone ! »

In the wild, the Schlegel pit viper adopts mainly a green color with shades of brown to aid in camouflage in the rainforest.

The Schlegel pit viper

According to the World Health Organization (WHO), a person is bitten by a snake every 6 seconds worldwide, some 5.4 million annually. Of these, 2.7 million develop clinical illness, and 138,000 die from complications. According to the World Health Organization (WHO,) snakebites are responsible for more deaths and disabilities than some tropical diseases. Without medical attention, snake bite venom can cause respiratory paralysis, hemorrhage, irreversible kidney failure, and tissue damage, leading to limb amputation. On May 6, 2019, the WHO adopted a strategy focusing on a 50% reduction in mortality and disability caused by snakebites by 2030. The challenge for the WHO is to manufacture species-specific anti-venom for each area and to make it affordable. This WHO initiative was proposed by Costa Rica as early as 2016. But now is the time to reassure the most anxious: no, you will most likely not get bitten by a snake on your trip to Costa Rica. Snakes are nocturnal and sedentary species. During the day, they hide from view and hunt only at night. Therefore, there is little chance of having a misadventure !

Puma, also called mountain lion is uniformly plain in hue. Its coat is tawny, reddish or grayish brown. Large males may weigh up to 250 pounds or more.

The Puma also called mountain lion

The felines

As I said at the beginning of this article, you can bump into all kinds of animals while strolling along one of the trails in the tropical forest. Many mammals use these trails, including felines. Shy and fearful, Pumas, Jaguars, or Ocelots are unlikely to attack. It is a challenge to see these six wild species of felines (Ocelot, Margay, Jaguar, Puma, Jaguarundi, and Oncilla) of Costa Rica in their natural habitat. You have a better chance of seeing them in a wildlife refuge than in the heart of the rainforest. The king of the felines, the Jaguar (from the Amerindian word “yaguar,”) is powerful and majestic. With a body length of up to 6 feet in length and weighing up to 348 pounds, it is the largest species of cat in the Americas and the third-largest in the world. The Jaguar is a well-muscled animal. Its coat features pale yellow to tan colored fur with darker rosette spots on the side.  Although in the heavyweight category, the Puma weighs only between 115 and 220 pounds. The Puma, also commonly known as Cougar or Mountain Lion, can reach a body length of around 7.9 feet from the nose to the tip of the tail.  It is the fourth largest in the cat family. The Puma’s fur varies in color from brown-yellow to grey-red. Unlike the Jaguar, its coat is uniform without any spots. Hunting at dusk and dawn, it is incredibly fast despite its weight! It can reach speeds of up to 50 miles per hour. Pumas are good jumpers. They can leap as high as 18 feet into the air and as far as 45 feet horizontally. The third-largest cat in Central America, the Ocelot, has a spotted coat in patterns unique to each individual. Because of its unique coat, the Ocelot was all the rage in the fur trade in the 1980s. It weighs between 18 and 34 pounds and reaches 15-20 inches at the shoulders.  It is also called « manogordo » in Costa Rica. Its powerful legs allow the Ocelot to be good at climbing. It is active at twilight and through the night. You have the best chance of seeing it lying or sleeping on a tree branch during the day. Finally, perhaps the strangest of the cat family in Costa Rica is undoubtedly the Jaguarundi (Puma yagouaroundi.) Contrarily to the other cats, the Jaguarundi is active during the day and hunts during the daytime and evening hours. Therefore, the probability of seeing it is greater. The Jaguarundi is about twice the size of a domestic cat and weighs 15 pounds. This close relative of the Puma, also called Eyra or Otter cat, looks more like an otter or a weasel. It has several characteristics observed in mustelids: an elongated body with relatively short legs, a small narrow head, small round ears, a short snout, and a long tail.

The Red-eyed tree frog is the unofficial symbol of Costa Rica. It has a vibrant green body with blue and yellow stripes on the sides and with orange or red toes.

The Red-eyed tree frog is the unofficial symbol of Costa Rica


What are the three iconic animals of Costa Rica ?

Now that I have described the rainforest as a « green hell » populated by dangerous species, where the heroes you face are aggressive, and with a multitude of insects that sting and dangerous, deadly snakes, let me show you the other side of the forest. No one is unaware of it, but Costa Rica is also a true Garden of Eden.

The Red-eyed tree frog

If I ask you the question, “what are the emblematic animal species of the Costa Rican rainforests?” I am ready to bet that the majority of you will invariably answer: the Red-eyed tree frog. The unofficial symbol of Costa Rica, this little red-eyed frog, is a festival of colors: a vibrant green body with blue and yellow stripes on the sides and with orange or red toes. Measuring between 1.5 and 2.75 inches as an adult, it is perfectly camouflaged in the rainforest despite its chromatic extravagance. It sleeps hidden under a palm during the day and only comes out at dusk when its clownish colors are much less vivid. This star of Costa Rica is found on the cover of books, on T-shirts, magnets, or mugs, and often represented as a Zen frog in full Buddhist meditation…

« If it were enough to settle in the lotus position to reach enlightenment, all frogs would be Buddhist ».
(Louis Pauwels – Les dernières chaînes)

Red-eyed tree frog is nocturnal and rests during the day. It is a slender, colorful frog by day and change to purplish or reddish brown at night.

The Red-eyed tree frog at dusk

The sloth

Let us continue our tour of the emblematic animal species of Costa Rica. For those who did not mention the Red-eyed tree frog as their first choice, it is a safe bet that you would have mentioned our friend « Flash Slothmore »,  the laziest of the Zootopie civil servants. There are two types of sloths, distinguished by the color of their fur and the number of claws. The Pale-throated Sloth (Bradypus tridactylus), also known as ai, is a species of three-toed Sloth. It is often called the three-toed Sloth or tridactyl. The Hoffmann’s Sloth (Choloepus didactylus), also known as unau, is a two-toed sloth.

« Laziness leads to contemplation; contemplation leads to beatitude ».
(Anatole France – On life and letters to Charles Morice)

To return to the ironic license plate of the sports car driven by Flash « FST NML » (consonants of Fast Animal), the Sloth is a very slow animal, moving only a few feet per minute, and sometimes difficult to spot in the tropical forest. Suspended from a branch, this arboreal mammal is barely distinguishable against the forest floor. This immobile or almost immobile ball of hair sleeps up to 20 hours a day, its main occupation being its extremely slow digestion… If a cow can take five days to digest kilos of grass, the Sloth needs more than four weeks… It lives in symbiosis with bacteria (only active in the presence of heat), which allows it to degrade the cellulose of the plants. To ensure its food transit, the Sloth must thus take regular suntan sessions !

The Pale-throated Sloth (Bradypus tridactylus), also known as ai, is a species of three-toed Sloth. It is often called the three-toed Sloth or tridactyl.

The Pale-throated Sloth (Bradypus tridactylus)

« That laziness is one of the seven deadly sins makes us doubt the other six ».
(Robert Sabatier – Le livre de la déraison souriante)

You will agree that being named after one of the seven deadly sins is not very glamorous… And yet, with its « Chewbacca »-like fur and its « Wolverine »-like curved claws, the Sloth is a fascinating animal. The body is covered with long hair, which grows, contrary to other mammals, from the belly to the back. This particularity is because the animal moves backward, with its back down. However, we cannot say that he is backward but rather that he has hair on his hand, right ? Its greenish fur contains an incredible ecosystem, a refuge for algae, bacteria, insects, and fungi, each of which plays a beneficial role for the animal. Its fleece, a veritable portable pharmacopoeia, is home to no less than 84 strains of fungi with powerful antibacterial and antiparasitic activities, notably against malaria and Chagas disease. « In the mushroom, everything is good » the Sloth could claim. The Sloth periodically descends from a tree, about once a week, to urinate and defecate at the foot of a nearby tree. It allows the moths, which colonize in number its fur, to lay eggs in its feces. The moths that decompose in the fur (thanks to the fungi) provide non-organic nutrients to algae, which provide the Sloth with the lipids that his vegetarian diet does not provide. Quite a team effort, isn’t it ?

A green Iguana is lying on a branch basking in the sun, posing perfectly for a nice photo.

A green Iguana is lying on a branch basking in the sun

The green iguana

Another species, frequently found in Costa Rican forests, lives its lazy life on trees: the Green iguana. As long as you keep your head up, you will have no trouble spotting a specimen lying on a branch basking in the sun, posing perfectly for a nice photo. The Green Iguana, also known as the common green iguana, is a large lizard. It has a stocky body and grows up to 4.9 feet in length from head to tail. The Green iguana is another emblematic animal of Costa Rica. Its back and tail are covered with spines. Its long and sharp claws and its sharp teeth could lead one to believe that it is a great predator when in reality, it is a harmless herbivore. The tail represents two-thirds of its total length and can be used as a whip to strike and wound. Despite the name, contrary to what we can think, the Green iguana can come in different colors and types depending on its region of origin and age. Its hue can take on different shades of green and be pinkish, bluish, or orange. The Green iguana is particularly appreciated for its meat and its eggs. It is called « chicken of the tree » in Costa Rica. This large lizard is now protected, and its consumption is forbidden.

Despite the name, the Green iguana can come in different colors and types. Its hue can take on different shades of green and be pinkish.

Green Iguana with shades of green and pinkish


Costa Rica: the paradise of butterflies and tropical birds

Finally, the overview of this Eden would be incomplete if we did not mention the many flying and colorful species that inhabit the tropical forests. Costa Rica is a delight for ornithologists, with more than 922 species of birds, and for entomologists with nearly a quarter of the butterflies known worldwide. Who does not appreciate the sight of a butterfly that twirls through the air ? Its large wings allow it a slow and more elegant flight than most other insects. Compared to its ten wingbeats per second, the bee flies at a rate of 200 beats per second. Don’t butterflies evoke a certain cheerfulness and harmony in our hearts when we see them fluttering around ? This is undoubtedly the true butterfly effect…

Heliconius cydno is a butterfly with elongated and rounded wings. It has a uniform dark color striped with a broad white band on the anterior wings.

The Heliconius cydno

One of the most beautiful is undoubtedly the Morpho, a large butterfly with a metallic blue hue, but there is also the Owl butterfly (Caligo) which is really lovely ! The Heliconius (sara, hecale, cydno) are fascinating butterflies: their variety is extensive, and their mimicry disturbing. They can quickly change color. This process of mimicry originates in a particular structure of their genome and consists of changing color to resemble toxic species and to thus escape predators who have learned not to eat insects of certain colors. In addition, Heliconius caterpillars feed on passionflower leaves, accumulating the toxins found in the leaves and storing them in their tissues. Caterpillars and adult butterflies are consequently unpalatable to predators. Another particularity of Heliconius is their diet. They are the only butterflies to feed on pollen in addition to nectar. This rich supply of protein gives them a lifespan of several months, unlike other butterflies that usually live only a few weeks.

The Keel-billed Toucan or rainbow-billed toucan has a long colorful banana-shaped bill that averages 4.7-5.9 inches in length.

The Keel-billed Toucan

Costa Rica is a paradise for birdwatchers. The observation of this spectacular avian diversity is an enchantment. There is nothing more pleasant than the peaceful and melodious song of the countless number of birds in the middle of nature. Costa Rica is a bird-rich country, and it is not easy to establish a shortlist of the most beautiful birds. There are some for every taste… The Asociación Ornitológica de Costa Rica (AOCR) mentions 922 bird species classified within 86 different families. With so many birds to choose from, I will mention the four most well-known families that inhabit the Costa Rican rainforests. We will discover the different species of birds as we go along our journey in the different regions. The Keel-billed Toucan (Ramphastos sulfuratus), also known as sulfur-breasted toucan or rainbow-billed toucan, is a colorful member of the toucan family. It is probably the most popular of all, with its long colorful banana-shaped bill that averages 4.7-5.9 inches in length, about one-third of the bird’s overall length. The hummingbird family is well represented by 52 different species. In addition to their flying ability, these Lilliputian birds (the Helena hummingbird weighs only about 0.069 oz.) have an impressive diversity in the iridescence of their feathers. The brilliant colors not only make the bird seem a tiny jewel, but, depending on the viewing angle, can change completely. An example is the female Green Violet-ear. The Helena hummingbird or the Bee hummingbird (Mellisuga helenae) is the smallest bird with a length of 2.2 inches.

Because of their iridescent feathers, the color of Green Violet-ears can vary greatly depending on the light and angle of view.

The Green Violet-ear

In the Woody Woodpecker family, Costa Rica has 16 species of woodpeckers that live in different regions, including the Black-cheeked Woodpecker (Melanerpes pucherani.) The Trogons include several truncated birds with colorful plumage, such as the Slaty-tailed trogon (Trogon Massena) or the Gartered trogon (Trogon Caligatus). The word trogon is Greek for « nibbling » and refers to the fact that these birds gnaw holes in trees to make their nests. The family Trogonidae is primarily known for the Resplendent Quetzal (Pharomachrus mocinno), a true symbol of Central American countries. This bird of about sixteen inches long and was sacred in the ancient civilizations of the continent, including the Aztecs. The name Quetzal comes from the Nahuati (Aztec) where quetzalli (from the root quetza = « stand ») meant « tall upstanding plume » and then « quetzal tail feather ». Thus, Nahuatl quetzaltotōtl means« quetzal-feather bird » or simply « quetzal ».

« Do like the bird
That lives on fresh air and fresh water, a bird
For hunting and fishing, a bird
That nothing ever stops, the bird, from going higher »
(Michel Fugain – Fais comme l’oiseau)

The Gartered Trogon adult male is iridescent blue in head and breast, iridescent green in the back, and have gray-blue bill, and bright yellow bellies.

The male Gartered Trogon

Finally, I could not end this ornithological overview without mentioning the national bird of Costa Rica (elected in 1977 from among several candidates,) the Yigüïrro (Turdus grayi), also called the tawny blackbird or the Clay-colored robin of the thrush family (Turdidae.) However, this bird has no aesthetic appeal: its plumage is brownish with a greenish-yellow bill and reddish-brown irises. It is relatively aggressive and has a rather unpleasant song, a rough and nasal sound. Its native name is Yigüïrro, an onomatopoeia transcription of its song. Why on earth is it the national bird of Costa Rica ? We must admit that the choice leaves us perplexed at first sight… It is undoubtedly because it is found throughout Costa Rican territory. All the inhabitants, especially farmers, know its unmistakable song announcing the rains. It is said that the Yigüïrro is the prophet of the rainy season, which is essential for agriculture and the renewal of the water table. It is said to bring luck when it chooses a house on which to establish its nest. The blue color in robin eggs is due to biliverdin, a pigment deposited on the eggshell when the female lays the eggs. There is some evidence that higher biliverdin levels indicate a healthier female and brighter blue eggs.

« Of all the animals of our fauna, it is the Yigüïrro that celebrates the first days of May with its song when spring arrives. It is the winged musician who, in the same way, sings in the rich man’s palace or on the threshold of the poor man’s house and who gives life to the healthy peace of our fields ».


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