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Adapting for Life in the Rainforest That little bit of rain we got over the weekend sure felt good. Sometimes I wish I could be magically transported to a place where it rains a lot—I mean really a lot—somewhere like the Amazon rain forest in South America. But what if we really could? Would you come along? Let’s go! Traveling the conventional way, we’d have to take at least three different planes. And then we’d need to hire a boat to take us up the Amazon River, deep into the rain forest. It would take hours or even days reach our destination some 6000 miles from home. But luckily we’ve got the magic thing going for us, so all we have to do is say a few magic words, snap our fingers and here we are… Wow, it’s wetter here, that’s for sure. Some parts of the rain forest receive about 400 inches of rain a year—that’s nearly 33 feet! Back in Tucson, we average only eleven inches. The Amazon doesn’t feel much cooler though—in the 80s—and the humidity! It’s like we just walked into a steamy bathroom after one of my sister’s hour-long showers. The Amazon Rainforest is the world’s largest rain forest, covering an area about the size of the continental United States. But it extends vertically, as well as horizontally. All around us are plants and more plants. Looking up, we catch only a few glimpses of sky; rays of light poke through here and there amid what looks like a ceiling of leaves. Some trees in the Amazon grow to fifty yards, as tall as a fifteen-story building! These giant trees house many insects and birds, including the world’s largest eagle, the South American Harpy. Scientists call these trees “emergents.” In fact, scientists have divided the rainforest into four strata or zones based on the living environment. Under the emergents is the canopy, a leafy world that is full of life, including insects, birds, reptiles, mammals, and more. Below the canopy is a cool, dark environment known as the understory. A few animals spend their lives in the understory, but most are just passing through. And beneath that is the forest floor. It is teeming with life, particularly insects. The largest animals in the rainforest, such as anteaters and jaguars generally live here as well. Running through the rain forest is the Amazon River. The world’s largest river in volume, it is fed by more than one thousand smaller rivers. The rivers, too, are full of life, including flesh eating piranhas, otters, caimans, and electric eels. But where are all the animals? Scientists estimate that one million species of plants and animals live in the Amazon rain forest—one third of all the species on earth. We’ve been here at least five minutes and haven’t seen a thing. Rainforest animals are often hard to spot. Some of the animals don’t want to be seen—and they have some pretty unique ways to accomplish it. But when we look very carefully, we see a cricket that looks just like a half eaten leaf thanks to false holes on its wing cases. And a stick that isn’t a stick at all—it just started to move! The wings of one moth look identical to the leaves it is resting on. Animals in the rainforest are adapted for survival in their unique environment in many ways, some by the structure of parts of their bodies or the way they move, and others by their coloring or behavior. Another reason we don’t see many animals right away is that most rain forest life exists in the canopy, the tangle of branches and vines in the treetops high above our heads. More than three-quarters of all rainforest creatures spend their whole lives in the canopy—almost a third of a football field above ground! A macaw calls from overhead, its feathers brilliant hues of scarlet, yellow, and blue. This showy bird is over three feet long from beak to tail. The macaw has few natural predators so has no need for camouflage. This macaw seems to be inviting us to join him. Lianas are huge climbing plants that grow up into the canopy by winding around other plants and using them for support. The native people use the lianas as a kind of hanging ladder to climb up into the canopy. We may as well give it a try (don’t look down!)… All around us the air is filled with the sounds of animals howling, squawking, buzzing, and twittering. One of the first things we notice is that many of the animals have some form of structural adaptation that helps them survive in this environment. The gliding gecko escapes danger by stretching its ribcage out into “wings” and turning itself into a miniature hanglider. A monkey uses its grasping tail as an extra arm, and the serrated or notched edges on the toucan’s bill enable it to bite off chunks of fruit. Many animals use a variety of adaptations. The chameleon can change color to blend in with its surroundings—protective coloration—but its eyes can also move in different directions at the same time—a structural adaptation.
Yellow, green, red, or even blue in color, the poison dart frog
oozes poison from its skin. Native people use the poison on the
tips of their blowpipe darts. Brightly colored animals are often
poisonous, and the colors warn predators to keep away. A brilliant
yellow and gold snake slithers by and startles us. But it’s
a harmless striped bronzeback snake. Some animals use bright colors
to copy the appearance of a poisonous animal and trick their enemies
into thinking they are dangerous. This is called mimicry. Another way animals protect themselves is through their behavior, such as the opossum’s ability to “play dead.” Giant otters are very social animals that find strength in numbers. They generally live in small, permanent family groups of four to six adults. An almost imperceptible movement draws our attention. The giant sloth is another resident of the canopy. In addition to its notoriously slow movement, the sloth has another form of protection. A green algae grows in its fur—the product of constant rainfall and moisture. The algae not only camouflages the animal, but also provides a delicious meal for a type of moth that lives in the sloth’s fur. This illustrates the interdependence, like a living jigsaw puzzle, that exists in the rain forest. The rainforest is one of the world’s most valuable resources, and in great need of preservation. Many of the products we use on a daily basis originate in the rain forest. One fourth of our prescription drugs come from plants and animals found only in the Amazon. Scientists hope some of the undiscovered plants in the Amazon will yield cures for many diseases. Even the very air we breathe is dependent on the rainforest where plants “breathe in” carbon dioxide and “breathe out” oxygen through a process called transpiration that filters pollution from the air. It’s time to go home now, but if we visit our local zoo, we can learn more about ways we can help protect the rainforest. Animal Adaptations Adaptations are the features of an animal that help it to survive in its environment. Adaptation also refers to the ability of an animal to adjust to various conditions in its environment. Some adaptations that rainforest animals use to survive include: Structural adaptations involve some part of the animal’s body, such as the body covering; the size and shape of its teeth, beak, or claws; or the way the animal moves. Protective coloration allows an animal to blend into its surroundings. Another word for this is camouflage. Mimicry allows an animal to look, sound, or act like a different animal. This fools predators into thinking it is poisonous or dangerous. Behavior adaptations include activities that help an animal survive; they may be instinctive (a behavior an animal is born with) or learned. Tune-up Your Mind
Journey to the Rainforest by Tim Knight Details Reid Park Zoo Fuel for Thought Many items that we use everyday come from the rainforest. Food items like chocolate, cola nuts (used to make cola soft drinks), many types of oils, a large variety of nuts including cashews and Brazil nuts, as well as many spices and teas all originated in the rainforest. Other useful rainforest products include aspirin, latex (an ingredient in rubber), kapok (used as a filling for life preservers, mattresses, and other forms of insulation), plants that are used to make rope and cord, and tropical timbers. Even chewing gum has its roots in the rainforest. At one time a white resin called chicle from the chicozapote, or sapodilla tree, was the base for all chewing gum. Now most gum is made from synthetic or man-made bases. It’s never totally dark in the rain forest. In some places the floor glows with light from luminous fungi. According to scientists, every half hour a plant or animal in the rainforest becomes extinct as a result of environmental abuse. |
