[2] The Llanos' main river is the Orinoco, which runs from west to east through the ecoregion and forms part of the border between Colombia and Venezuela.

Shrubs and herbs are most commonly legumes in the genera Mimosa, Cassia, Desmodium, Eriosema, Galactia, Indigofera, Phaseolus, Stylosanthes, Tephrosia, and Zornia.

Common trees include Tabebuia billbergii, Godmania aesculifolia, Cassia moschata, Spondias mombin, Copaifera pubiflora, Bourreria cumanensis, Cordia spp., Bursera simaruba, Cochlospermum vitifolium, Hura crepitans, and Acacia glomerosa.

Typical shrubs are Bourreria cumanensis, Randia aculeata, Godmania aesculifolia, Pereskia guamacho, Prosopis spp., Xylosma benthamii, Erytroxylum sp., and Cereus hexagonus.

[2] Mammals of the grassland and savanna include white-tailed deer (Odocoileus virginianus), giant anteater (Myrmecophaga tridactyla), capybara (Hydrochoerus hydrochaeris), giant armadillo (Priodontes maximus), Eastern cottontail (Sylvilagus floridanus), Alston's cotton rat (Sigmodon alstoni), Hispid cotton rat (S. hispidus), Zygodontomys brevicauda, and Oecomys bicolor.

[2] The gallery forests are home to more diverse large and medium-sized mammals, including collared peccary (Tayassu tajacu), white-lipped peccary (T. pecari), South American tapir (Tapirus terrestris), white-tailed deer, red brocket (Mazama americana), wedge-capped capuchin (Cebus olivaceus), Venezuelan red howler (Alouatta seniculus), large rodents like the lowland paca (Cuniculus paca), agoutis (Dasyprocta spp.

[3] A large portion of the distribution of the sharp-tailed ibis (Cercibis oxycerca) and white-bearded flycatcher (Phelpsia inornata) is in the Llanos.

An 1856 watercolor by Manuel María Paz depicts sparsely populated open grazing lands with cattle and palm trees.

[5] The term llanero ("plainsman") became synonymous with the cowhands that took care of the herds, and had some cultural similarities with the gauchos of the Pampas or the vaqueros of Spanish and Mexican Texas.

In Los Llanos, the governments of Venezuela and Colombia developed a strong oil and gas industry in Arauca, Casanare, Guárico, Anzoátegui, Apure, and Monagas.

The Orinoco Belt, entirely in Venezuelan territory, consists of large deposits of extra heavy crude (oil sands).