The cloud forest has tremendous animal diversity. Hummingbirds are easily attracted. Birdwatchers may observe numerous species of brightly-colored birds, perhaps even the reclusive Resplendent Quetzal (Pharomachrus mocino ), or listen for the liquid song of the jilguero or Mountain Robin (Turdus plebejus ). Some birds can easily be photographed. For instance, the Collared Redstart (Myioborus torquatus), or “friend of man”, is not shy; it may fly towards one’s camera. Many birds, such as the redstart and the Black Guan (Chamaepetes unicolor ), are endemic to the Talamanca highlands.
Mammals are not easily seen, but the park shelters jaguars, peccaries (wild pigs), tapirs, spider monkeys, squirrels, tayras, and many other species. At left is a mono colorado or spider monkey (Ateles geoffroyi) recently spotted on the Cloudbridge Reserve. Reptile lovers can find many lizards that are endemic to the highlands, such as the spiny lizard found mostly in the paramo. Snakes, such as the parrot mountain snake, also inhabit the cloud forest, but in general, snakes are rarely seen. Insect life is abundant at lower elevations, but diminishes the higher one goes.
Costa Rica offers amazing biodiversity and opportunities for research. According to INBio, researchers know 98.8% of vertebrates (excluding fish), close to 90% of plants and 60% of fish. However, out of the most diverse group (arthropods), less than 20% of species have been described. The same goes for other invertebrates, excluding mollusks. Groups such as fungi, bacteria and virus are almost unknown, since more than 98% of expected species have yet to be described.