The tropical rainforests of Latin America, Africa, Asia and Australasia are famously diverse in biological terms. Nourished by plentiful rainfall and relatively stable, warm temperatures, they are also often very old landscapes. All this equates to a dizzying array of animal life, from leaf-cutting ants and swamp-lurking crocodilians to high-canopy primates and big mammal-hunting eagles. Many tropical rainforests show distinct layers of ecological activity, each with their own roster of regular animal visitors and inhabitants.
The largest members of a tropical rainforest's fauna community inhabit the forest floor, as do myriad insects, ground-foraging birds and soil organisms. In the rainforests of central Africa, a number of quite hefty creatures frequent this shadowy terrestrial zone: forest elephants, bongo, lowland gorillas, leopards and okapi, to name a few. In South America, jaguars, tapirs, bush dogs and white-tailed deer are a few of the forest-floor large mammals. Smaller mammals like Latin American goutis and African hedgehogs also live here, as do reptiles like the venomous fer-de-lance of South America.
The understory consists of relatively short trees and shrubs creating a sub-forest within the shade of much larger canopy trees. This is an ecologically rich level, supporting many animals active primarily here, or that range higher into the rainforest canopy or drop down frequently to the forest floor. For example, two kinds of rainforest big cats--the jaguar of the New World and the leopard of the Old World--readily climb trees to hunt and rest. Many possums of Australian rainforests will travel from understory to ground and canopy.
A vast array of animals roam the canopy layer, consisting of the tall, mature rainforest trees and their upper branches and crown. Birds like macaws in South America forage here for nuts and fruits; others, like woodpeckers, target insects. Monkeys are common in the canopies of both New World and Old World rainforests; those of the former zone are distinguished by their prehensile tails. While African great apes are as terrestrial as they are arboreal, the rainforests of Southeast Asia support an ape that is essentially a canopy specialist, the orang-utan.
The summits of the tallest rainforest trees constitute the emergent layer, which rises above the densest layer of canopy. This lofty zone is patrolled by large raptorial birds. Two of the biggest eagles in the world, the harpy eagle of Latin America and the Philippine eagle of Southeast Asia, hunt monkeys and other large prey in rainforests, cruising and perching in this layer.