Canoes are vital for transportation on the rainforest rivers of the Republic of the Congo. The Congo Basin’s 500 million acres of tropical forest, second-largest in the world after the Amazon, are known for an incredible array of wildlife, including great apes, forest elephants, and some 700 species of river fish. People have also lived here for over 50,000 years. The Congo Basin provides water and food to about 75 million Africans.

A scarlet macaw is caught munching a snack in Brazil's Amazon rainforest. These birds are best known for their loud cackles, four-toed feet, and brilliant plumage.

Limited space in dense rainforests results in many unique plants, like this fig tree in the Philippines. It produces fruit on runners that come from its trunk instead of on its branches.

A lizard suns itself on a leaf in the El Yunque National Forest in Puerto Rico. El Yunque is the only tropical rain forest in the U.S. National Forest system, which protects the 28,000 acres (11,331 hectares) in the Luquillo Mountains.

A monkey from the Malaysian rain forest digs into a coconut snack. Malaysia is still heavily forested, about 60 percent of the nation is tree-covered, but deforestation has proceeded rapidly during the nation’s recent economic development. Rain forests harbour tremendous biodiversity and those covering Peninsular Malaysia’s highlands also give rise to the rivers which supply 90 percent of the nation’s freshwater needs.

Streams on Costa Rica’s remote Osa Peninsula flow through one of the world’s outstanding examples of lowland tropical rain forest, protected here by Corcovado National Park. Costa Rica’s signature park boasts an array of colourful flora and fungi and an amazing variety of larger animals, from estuary-dwelling crocodiles to secretive jaguars.

A species of mushroom called Amanita muscaria or fly agaric dots the floor of a temperate coastal rainforest in the Canadian province of British Columbia. Identified by the white patches on its cap, this species of fungus can grow up to a foot high, with a top as big as a dinner plate. It is referred to as fly agaric because people have been known to use pieces of the mushroom to attract and kill flies.

Moss drapes a stand of Sitka spruce in the Hoh River Valley, a U.S. temperate rainforest in Washington State. Trees here often host plants that grow on other plants, such as moss.

The cassowary has an intimidating stare and the bulk to back it up. These Australian rain forest-dwellers are the second-largest birds in the world, reaching 1.7 metres (5.5 feet) and 70 kg (155 pounds) and looking up only to the ostrich. Cassowaries tend to avoid humans but can use their powerful legs and dagger-like nails to deliver punishing blows to any aggressors. Though they run, jump, and swim well, cassowaries cannot fly.

Baby white-faced capuchin monkeys play in a Costa Rican rainforest. Unlike these familiar faces, the majority of rainforest species are yet to be named, formally described, or analysed.

The rhinoceros hornbill is named for its characteristic “casque,” the strange structure situated on top of the bird’s bill. The uses of this “horn” aren’t fully understood but casques may play a role in attracting mates or amplifying bird calls. Rhinoceros hornbills feed mainly on fruit found in rainforest trees. They typically live in pairs and are known for an unusual nesting strategy, during which the male seals up the female inside a hollow tree, leaving only a tiny beak hole through which to feed her and their young.

The red-eyed tree frog is an icon of the Central American rain forest. When asleep, it's green colour provides effective camouflage. When threatened, the red of suddenly-exposed eyes or legs may startle predators and enable an escape. Female frogs lay eggs on leaves overhanging water so that their tadpoles will fall into ponds. The tadpoles feed on insects in the water until they develop into frogs and take to the trees.

Climber John "Razor Sharp" Benson weaves through skin-ripping pinnacles. In Malagasy, the formations are called tsingy, meaning "where one cannot walk barefoot." The terrain resists intrusions from hunters, hungry cattle, and wildfires.

See more pictures from the feature story "Living on a Razor's Edge."