| There are an astounding number of ways in | | | | birds and flying reptiles are alike in having |
| which animals move on the land, in the air | | | | bones. An insect's wing, like an insect's |
| and in water.Land-dwelling mammals can to | | | | body, has no bones at all. The veins that |
| walk, run and jump. Salamanders, turtles and | | | | strengthen its wing are really air tubes with |
| lizards also walk, but are often said to | | | | strong walls.A great many animals also live |
| crawl. Termites and ants are among the many | | | | in the water, primarily because there is much |
| insects that walk a great deal too. | | | | more room for them than on land. Mammals, |
| Grasshoppers and crickets jump, but they also | | | | such as dolphins and whales, live only in the |
| walk about slowly when they are eating. Even | | | | water. Many birds do a great deal of |
| flying birds must be able to walk or hop on | | | | paddling about in the water. Reptiles, like |
| land. The garden snail produces a watery | | | | turtles and amphibian animals, like frogs, |
| liquid that serves as a private lake. This | | | | can also live half their lives in a body of |
| snail rolls through this lake by contracting | | | | water. But most of the swimming animals |
| muscles that move its skin. This is also | | | | belong to the class of fishes. The movement |
| another form of animal movement on land.Many | | | | of a fish's tail fin helps propel a fish |
| animals live in the ground and must get from | | | | through the water. Yet many fish can still |
| place to place. Moles and other burrowing | | | | swim even if most of the tail fin is a bitten |
| animals dig their way through the earth | | | | or cut off.They can push themselves through |
| rapidly with shovel-like legs. Earthworms | | | | the water by twisting their bodies from side |
| often eat their way through. When the soil | | | | to side. Some fish can also move forward or |
| is loose, they push through it in the same | | | | backward by means of their side fins. Other |
| way that they move on the surface of the | | | | animals move through the water by jet |
| ground. A worm also moves about by digging | | | | propulsion. Squids and cuttlefish suck water |
| into the ground and making itself longer and | | | | into their bodies and then squirt it out. |
| then shorter. In this way it pulls itself | | | | This shoots them forward. Jellyfish also |
| ahead.Several other animals fly through the | | | | swim by jet propulsion. They open their |
| air to transport themselves. Others, like | | | | jelly umbrellas and then rapidly close them. |
| flying squirrels, flying frogs, flying fish | | | | When the stream of water gets out, the |
| and flying lizards do not really fly but | | | | jellyfish is pushed forward. Many tiny |
| instead glide through the air. The best | | | | animals row themselves through water. They |
| gliders are the flying fish that leap from | | | | have tiny hairs called cilia which act as |
| the water with such force that they can glide | | | | oars. Other tiny creatures have whiplike |
| as far as 50 yards.A true flying animal has | | | | threads with which they pull themselves |
| the ability to propel itself through the air | | | | forward.There are still more curious ways in |
| by beating its wings against the air. Only | | | | which animals move. Some ride from place to |
| four groups of animals have produced species | | | | place on other animals, like the remora fish. |
| that can truly fly: they are the bats, the | | | | It fastens itself onto sharks or other big |
| birds, the insects and the flying reptiles | | | | fish so that when the sharks kill another |
| that died out with the dinosaurs. Each group | | | | fish, the remora frees itself to go after a |
| has its own kind of wing design and | | | | part of the meal. |
| aerodynamics. However, the wings of bats, | | | | |