Costa Rica supports an enormous variety of wildlife, due in large part to its geographic position between the North and South American continents, its neo-tropical climate, and its wide variety of habitats. Costa Rica is home to more than 500,000 species, which represents nearly 5% of the total species estimated worldwide, making Costa Rica one of the 20 countries with the highest biodiversity in the world. Of these 500,000 species, a little more than 300,000 are insects.
A key of Costa Rica's biodiversity is the been part of the bridge connecting the North and South American continents approximately three to five million years ago. This bridge allowed the very different flora and fauna of the two continents to mix.
There are about 1,251 species of butterflies and at least 8,000 species of moths. Butterflies and moths are common year round but plentiful during the rainy season.
Costa Rican butterflies and moths have made amazing adaptations to the environment. Some examples of these are the following: Swallowtail caterpillars imitate bird droppings and many others have bright colors to warn predators of bodily toxins.
Ecotourism is one of Costa Rica’s primary economic resources, and the country's butterflies add a lot to that. They bring life to rainforests, not only with the diversity in color, but with the magnificence of the flowers that they help pollinate.
Invertebrate species make up most of Costa Rica’s wildlife. Of the estimated 505,000 species, about 493,000 are invertebrates (including spiders and crabs). It is known that there are tens of thousands of insects and microscopic invertebrates in every land type and elevation level. However, they are largely unnoticed or unidentified.
There are known 183 species and subspecies of terrestrial gastropods from Costa Rica and numerous freshwater gastropods and bivalves.
Costa Rica is home to around 175 amphibians, 85% of which are frogs. Frogs in Costa Rica have interesting ways of finding fishless water to raise their young in.
Notable frog species in Costa Rica include Red-eyed Tree Frog, a few species of Poison Dart Frogs, the semitransparent glass frogs, and the large Smoky Jungle Frog. Some other notable toad species in Costa Rica include the ten species of Bufo toads and the Giant toad, a huge toad known for its wide appetite. It has been documented eating almost anything, including vegetables, ants, spiders, any toad smaller than itself, mice, and other small mammals.
Besides the frog species, approximately 40 species of lung less salamander and two species of caecilian are found in the country, both rarely-seen and little known.
Approximately 225 reptiles are found in Costa Rica. This includes over 70 species of lizards, mostly small, forest-dwelling anoles. Large lizards such as the striped basilisk, Black iguana and Green iguana are probably the country's most regularly-encountered reptiles. Snakes number about 120 species in the country, including 5 powerful boas and a wide diversity of harmless snakes. There are about 20 venomous snakes, including colorful coral snakes and various vipers such as the common eyelash viper and two formidable venomous snakes, bushmaster and Fer de Lance. Among turtles, 5 of the world's 7 species of sea turtles nest on the nation's beaches. Two crocodilians, the widespread Spectacled Caiman and the large, sometimes dangerous American Crocodile are found in Costa Rica.
Costa Rica is home to nearly 250 species of mammal. Medium-sized forest-dwelling mammals are often the most appreciated mammalian fauna of the country. These include four species of monkeys such as the frantic White-headed Capuchin and noisy Mantled Howlers; two species of sloths; the opportunistic White-nosed Coati; and the fierce predator, the Tayra.
Bats comprise more than half of the mammal species in the country, unusually outnumbering rodents twice over. Their bats are adapted to various foraging methods and foods; including nectar, fish, and insects and parasitized blood, as the case with the infamous vampire bats.. Large fauna, such as tapir, jaguar, and deer are rarely encountered, being both elusive and tied to now-fragmented undisturbed habitats.