Zoologists study animals in many different ways. One useful way of thinking about animals is according to where they live. Of course, where an animal lives its habitat is related to its anatomy. Physical traits that enable an anima! to survive in a particular place may be passed to offspring. Natural selection may enable more of these offspring to survive than do offspring that lack these traits. Such helpful adaptations may spread to the whole species over time.
Seven major habitats are found all over the world. Each habitat supports many kinds of animals.
Tropical rain forests
These warm, humid forests are home to more species than any other habitat on Earth. Monkeys, bats, tree boa constrictors, colorful parrots and macaws, and wasps and beetles live in the overhanging layer of foliage called the rain forest canopy. Mammals such as jaguars, tigers, tapirs, and anteaters prowl in the forest below. In African rain forests, chimpanzees and lowland gorillas spend their lives between the ground and the trees. Crocodiles and fish swim in rivers and ponds.
The world’s grassy plains areas support herds of herbivores such as gazelles, gnus, zebras, and bison. Carnivorous predators such as cheetahs, lions, and hyenas roam the African grasslands—called savannas—searching for such prey. Other animals of the African savannas range from the elephant, rhinoceros, and hippopotamus to the giraffe, ostrich, and termite. Animals of other grasslands include the Australian kangaroo and wombat, the South American cavies and increasingly rare pampas deer, and the North American coyote, pronghorn, and prairie dog.
Same animals are adapted to survive in the march, dry climates of the world’s deserts. These include centipedes and scorpions; insects, such as bees and butterflies; reptiles, such as rattlesnakes and Gila monsters; birds, such as elf s and roadrunners; and mammals, such as kangaroo rats, mule deer, and dingoes. Many desert animals have light-colored skin, which reflects sunlight. Some, such as the desert fox and the desert hare, have large ears that help them get rid of body heat.
Unlike tropical rain forests, temperate forests often have thick underbrush. Mammals small enough to move through this growth include chipmunks, opossums, raccoons, and squirrels. Larger forest mammals include various species of bear and deer. The koala lives in the temper-ate forests of Australia. Numerous birds of different species nest in the trees and shrubs.
Salamanders are common, as are snails. Fish, frogs, and turtles live in forest ponds and streams.
The mountains are home to many animals, and the species vary with the altitude. At lower and therefore warmer elevations, bear, deer, elk, llamas, vicunas, and yaks find food and shelter.
Spiders and insects, such as butterflies and grasshoppers, also live at this level. Above the tree line, where the climate is colder and the air is thinner, bighorn sheep and mountain goats thrive on the rocky slopes. High on the snowy peaks, only a few insects, spiders, and ice worms can survive.
The ocean is home to some of the smallest animals in the world as well as the largest—the blue whale. Some lobsters, sea urchins, and numerous species of tropical fish prefer warm’ tropical ocean waters while live anemones, barnacles, and starfish are found along the shore. Even in the dark, cold waters of the ocean depths, such specially adapted animals as the angler fish survive.