Seventy percent of rain forest plants are trees, most of which are well over 100 feet tall to reach the sun above the dense forest canopy. Rain forests have evolved so that no tree species dominates any ecosystem. That variety ensures animals a year-round supply of fruits and flowers to eat and prevents mass tree extinctions from pests and diseases. One of the most striking trees in the Amazon rain forest is the kapok tree. The kapok --- the Amazon's largest tree --- can grow to more than 200 feet, and houses animals ranging from frogs to bats. Dipterocarp trees are especially important to rain forests in Southeast Asia. Dipterocarps exceed 150 feet in height. They enjoy a protective resin that keeps parasites at bay.
These plants grow on branches and on trunks and leaves of trees. Epiphytes common in tropical rain forests include mosses, ferns and lichens. Orchids are perhaps the best-known epiphyte, and with nearly 20,000 varieties, they're among the most diverse flower species in the rain forest. Many orchids are endemic to their specific, small area, not growing in other parts of a rain forest. Bromeliads, with their thick leaves and cupped leaves, are pineapple relatives capable of holding rainwater for snails, flies and mosquitoes.
Vines represent a major share of a rain forest's plant network. Liana vines, related to the popular philodendron houseplant, comprise the biggest vine group. Some liana varieties, such as the rattan version that makes up wicker furniture, can grow to more than 600 feet. Not all vines live harmoniously with rain forest trees: strangler vines sap food and energy from host trees until the trees hollow out.
All rain forests harbor monkeys. And among rain forest monkeys, all are prehensile, so they can use their tails to curl around and grasp at tree branches and vines. Spider monkeys are common to rain forests. Named for their arachnid-like appearance when they dangle from branches using their limbs and tail, spider monkeys rank as some of the larger monkeys in rain forest ecosystems. They can grow to a height of nearly 2 feet, excluding their tails. Their coat colors range from red to tan to black. They live in canopies, subsisting on fruits and seeds. Smaller capuchin monkeys don't grow beyond 10 lbs., and leave their rain forest tree habitats only for water. They eat vegetation, bugs and birds. Howler monkeys, named for the loud cries they issue to defend their territory, can grow to 3 feet.
Rain forests host thousands of insect varieties, some of which have yet to be identified, classified or named. Butterflies and moths are essential to pollinating rain forest trees. Beetles are important to the forests' life cycles, as they eat and clean up dead animals and decaying leaves, bark and other plant matter. Dragonflies help control the numbers of other insects. Other common rain forest insects include mosquitoes, praying mantises, ants and camouflaged stick insects, which blend into the trees and bushes they occupy.
Birds are important rain forest residents because they eat plant seeds and disperse them in their waste. Dozens of varieties of colorful toucans inhabit rain forest trees. Toucans eat not just berries, but smaller birds and lizards as well. At as much as 3 feet in length, with tails longer than their bodies, macaws represent the largest species of parrots. Macaws eat nuts, fruits and seeds. Rain forests in Central America alone harbor more than 300 types of hummingbirds, which spend their days pollinating flowers and eating spiders and gnats. Brightly-colored quetzals are known for their long, graceful tails.
These mammals move so slowly that algae grow on their fur. Sloths come in two varieties: two-toed and three-toed. They typically weigh around 20 lbs., and spend most of their day sleeping upside down. They subsist on leaves, buds and twigs, and need little food thanks to a slow metabolism. Because their slow movement is a liability when facing predators, sloths rarely leave rain forest trees.
Virtually every type of reptile occupies turf in one of the world's rain forests. Alligators, caimans, crocodiles, caped lizards and turtles --- all maintain representative species in rain forests. Red-eyed tree frogs boast striking scarlet eyes and a multicolored body. A single poison-arrow frog's toxin, which rain forest natives apply to their spears for hunting, could kill 100 people. The emerald tree boa resides near swamps and marshes and lives on rodents and birds. The Amazon's carnivorous anaconda, which is the world's largest snake, can grow to nearly 40 feet. It eats boar and deer, among other larger animals.
Rain forests all feature cats in their animal lineups. The jaguar, which inhabits rain forests in South and Central America, can grow to as long as 6 feet. The smaller ocelot, also from the Americas, will reach a maximum of 3 feet and eat small mammals, birds and reptiles. Ocelots will even hunt in trees. The serval, a dweller of African rain forests, is a small, spotted cat that grows to a little more than 3 feet. The serval eats a broad array of animals, ranging from mice to antelopes.
