Combined with high humidity and daily average temperatures of around 23.89 °C (75 °F), the foundation is set for a lush landscape brimming with species, harboring a huge wealth of plant, animal and fungal biodiversity.

Numerous epiphytic lianas (vines and crawlers) belonging to the family Araceae use these trees for support systems (such as Anthurium, Monstera and Philodendron).

Growing along the sheltered forest floor are unique and varied species of plant families like Marantaceae, Piperaceae, Orchidaceae and Bromeliaceae, as well as many ferns, jungle cacti, mosses and lichens, among others.

With such a difficult environment to access, and with relatively few options to climb the socioeconomic "ladder", certain areas of the forest have been significantly altered for ranching and agriculture, and the land is continuously being threatened by the prospects of oil, logging and paper pulp industries, as well as the unregulated mining of gold (and other metals), coca growing (with armed guards) and more—both official and clandestine.

The forests are bounded to the east by the Andes, which separates them from the Amazon and Orinoco basin eco-regions of Brazil, Venezuela and eastern Colombia.

[1] Subregions include the hilly region of Darién and Urabá in the north; the Pacific coastal zone with elevations up to about 500 metres (1,600 ft); the central strip; the hills of the El Carmen de Atrato and San José del Palmar municipalities; and the rainforest along the western Andes up to an elevation of about 1,000 metres (3,300 ft).

The heavy rainfall gives these rivers great power, cutting deep gorges through the mountains with dramatic falls and rapids in the upper reaches.

The central region receives the most rain, in some areas as high as 13,000 millimetres (510 in), while the north and south are comparatively drier, and in some parts have short dry seasons in January–March.

Vegetation includes formations that would otherwise be found only in cloud forests, with thick moss and other types of non-vascular epiphytes on the tree trunks and branches, and with diverse species of woody hemiepiphyte lianas of the Ericaceae, Marcgraviaceae and Melastomataceae families.

The extremely high rainfall makes it difficult for many vertebrates to travel, forming gap in the distribution of several primates and other mammals.

Vulnerable or endangered mammal species include Geoffroy's tamarin (Saguinus geoffroyi), giant anteater (Myrmecophaga tridactyla), cougar (Puma concolor), ocelot (Leopardus pardalis) and jaguar (Panthera onca).

These include the Choco tinamou (Crypturellus kerriae), Baudó oropendola (Psarocolius cassini), viridian dacnis (Dacnis viguieri), crested ant tanager (Habia cristata), Lita woodpecker (Piculus litae) and plumbeous forest falcon (Micrastur plumbeus).

Other rare birds include the harpy eagle (Harpia harpyja), black-and-white hawk-eagle (Spizaetus melanoleucus), and perhaps the speckled antshrike (Xenornis setifrons), although this last may no longer be present in Colombia.

[1] Endangered birds also include great green macaw (Ara ambiguus), rufous-brown solitaire (Cichlopsis leucogenys), banded ground cuckoo (Neomorphus radiolosus), Baudo guan (Penelope ortoni) and Baudó oropendola (Psarocolius cassini).

[1] Endangered reptiles include Dunn's spinytail lizard (Morunasaurus groi) and Boulenger's least gecko (Sphaerodactylus scapularis).

The Chocó forests supply half of Colombia's wood, and the main threat comes from deforestation and resultant erosion.

Other threats come from plantations of African oil palm (Elaeis guineensis), gold mining and coca growing.

[1] In Colombia, as of 1997 about 2,013 square kilometres (777 sq mi) was protected by widely separated national parks, covering 2.5% of the ecoregion and 1% of the original habitat.