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Discusses twenty-nine animals and plants that have unusual distinctions such as fastest ...
Discusses twenty-nine animals and plants that have unusual distinctions such as fastest runner, biggest eater, largest living thing, longest sleeper, keenest sense of smell, and oldest living thing.
The Fastest Runner
The cheetah is the fastest runner in the world. It has been clocked at up to 70 miles an hour—faster than the fastest racehorse. (The fastest a human has ever run is less than 28 miles an hour.) The cheetah is a sprinter, not a long-distance runner. In its home in the grasslands of Africa, its speed helps it to catch food. In the cooler parts of the day, in the early morning or just before sunset, the cheetah hunts. When it sees an antelope or gazelle, it slithers through the grass until it is less than 200 yards from its prey. Then it puts on an incredible burst of speed. Within two seconds, it goes from a standing start to a speed of 45 miles an hour. If the antelope or gazelle sees the cheetah in time, it dashes off, zigging and zagging frantically. If it can stay ahead of the cheetah for just 20 seconds or so, the spotted speedster will probably tire and give up the chase. But if the cheetah catches up with its prey, it knocks the fleeing animal over with its paw and quickly pounces on it.
Cheetahs are often called "hunting leopards." Both cheetahs and leopards are members of the cat family, and both have yellow fur with black spots. Both big cats hunt for food, but cheetahs can be tamed and trained to do their hunting for human masters as well. Carvings on Egyptian tombs several thousand years old show people taking the big cats on hunting expeditions. Marco Polo told of how Kublai Khan, the Mongol conqueror of China, hunted with cheetahs in the thirteenth century. Tame cheetahs sat with their masters on horseback and then jumped to the ground when the game was sighted.
Some people have kept cheetahs as pets. But these cats can be dangerous playmates. Although they are as playful and affectionate as kittens (they even purr when they are petted), they may accidentally give a nasty scratch with their claws. The cheetah is an unusual cat. It is the only one that cannot pull in its claws.
Today cheetahs are in danger. They are fast disappearing from many parts of Africa and Asia. People have cleared so much land for farming that the cheetahs have fewer places to hunt. And in many areas the antelope and deer on which they feed have been wiped out. So many cheetahs starve to death. Hunters have killed thousands of cheetahs for their beautiful fur coats, or just for the sport of it. Scientists and nature lovers are trying to stop the slaughter of cheetahs and the other great cats. Unless they are successful, nature's champion runner may disappear from the world forever.
70 miles = 112.6 kilometers
28 miles = 45.0 kilometers
45 miles = 72.4 kilometers
200 yards = 182.8 meters
The Largest Reptile
THE SALT-WATER CROCODILE
Once, long ago, giant dinosaurs ruled the earth. The dinosaurs are gone now. Only some bones and fossil footprints remain to tell us that they once lived. But some of their relatives, the crocodiles and alligators, have survived. Scientists believe that they have changed very little over the last 70 million years.
The largest of all the living reptiles are the salt-water crocodiles. The biggest one ever measured was a huge man- eater killed in the Philippines in 1823. It measured 27 feet from the tip of its snout to the end of its tail. Its weight was estimated at a full two tons.
Crocodiles spend part of their time in water and part on land. They can lie in the water, mostly hidden, with only their nostrils and eyes showing above the surface. During the day, they often drag their long, scaly bodies up onto the bank to sun themselves. Basking in the sun warms their bodies. When they get too hot, they move into the shade or slide back into the water again.
When a crocodile is basking, it is peaceful and drowsy. Shore birds may hop about it without fear and even walk right into the crocodile's wide-open jaws to peck at the leeches clinging to its gums. But when a crocodile is hungry, it is a raging fury. It may knock its prey into the water with a swipe of its powerful tail, or grab it with a sideways snap of its huge jaws. The muscles that open a crocodile's jaw are very weak—so weak that a person could hold them shut with one hand. But the muscles that close its jaws are incredibly strong. French scientists found that a 120-pound crocodile could close its jaws with a force of 1,540 pounds. And a larger crocodile would be even stronger. Once the crocodile has its prey in the water, gripped in its powerful jaws, it pulls the victim under and drowns it. Then the crocodile rolls over and over until the prey is torn into chunks, which the crocodile gobbles down whole.
The terrifying stories of man-eating crocodiles are quite true. It is believed that salt-water crocodiles kill more than 2,000 people· each year in Asia, the East Indies, and Australia. The crocodiles of the Nile in Africa are also killers.
The female crocodile is a devoted mother. She builds a mound of earth as a nest for her eggs and stays close by to defend them for ten weeks or more, until they hatch. The baby crocodiles grunt when they are ready to hatch, and their mother digs them out. For a few days, they follow her around like baby ducklings. Then they scatter.
No one is sure how long a crocodile lives. But since they continue to grow slowly all their lives, it is believed that the biggest ones may be over 100 years old. In recent years, so many crocodiles have been hunted and killed for their skins that few have a chance to survive to great age. So large crocodiles have become very rare.
27 feet = 8.2 meters
2 tons = 1.8 metric tons
120 pounds = 5.4 kilograms
1,540 pounds = 698.5 kilograms
The Largest Bird
What has two legs and is bigger than a basketball player? The ostrich, the world's largest living bird. It may stand eight feet tall and weigh as much as 300 pounds. It looks like a clumsy giant, but it is one of the swiftest runners in the animal kingdom. Running ostriches have been clocked at 50 miles an hour. Their two-toed feet are good for something else, too—kicking enemies. An ostrich's kick is so hard, it can break a lion's back!
The ostrich is a bird, but it can't fly. Its body is so heavy that its tiny wings could never lift it off the ground. And it does not have the right kind of feathers for flying. Ostrich feathers curl to form separate fluffy plumes. When an ostrich is sitting on its nest, it spreads its wings out like thick blankets to cover the eggs and keep them at just the right temperature.
Ostrich eggs are another reason for calling this bird one of nature's champions. They are the largest eggs laid by any bird—up to eight inches long and weighing as much as three pounds. You would need two dozen chicken eggs to make an omelet as large as you could make from just one ostrich egg.
In the 1700s, ostrich feathers were the height of fashion. Every well-dressed woman had to have a hat trimmed with ostrich plumes and an ostrich-feather fan. Hunters in Africa and Asia shot ostriches by the millions. Soon there were so few that it seemed they might disappear. But then it was found that the big birds could be raised on farms. Their feathers could be clipped off without even hurting the ostriches. In time the feathers grew back, and in less than a year they were ready for clipping again. Millions of ostriches were raised on farms in South Africa, Australia, and the United States. The best feathers sold for $500 a pound, and ostrich farmers made fortunes.
Then, suddenly, feathers went out of style. Ostrich farmers killed their birds or turned them loose. Soon they were scarce again. Now they are plentiful only in East Africa. There they roam with herds of zebras, gazelles, and other grazing animals. With their long necks and keen eyes, they act as "lookouts," warning other animals of danger.
Have you heard that an ostrich hides its head in the sand and thinks it is hiding from its enemies? The big bird is not as silly as that. What it really does when danger approaches is to lie down and stretch its neck out flat along the ground. From a distance its body looks like a bush or a lump of earth, and the enemy may not notice it.
8 feet = 2.4 meters
300 pounds = 136.0 kilograms
50 miles = 80.5 kilometers
8 inches = 20.3 centimeters
3 pounds = 1.4 kilograms
The Most Shocking
THE ELECTRIC EEL
All living things produce electricity. In most animals and plants, the pulses of electric current are so tiny that special instruments are needed to detect them. "Brain waves," for example, can be picked up by metal wires and disks called electrodes, pasted to a person's scalp. An electrocardiogram records the pulses of electricity from the heart. But some fishes are able to produce enormous amounts of electricity—enough to stun or even kill. The most powerful of these electric fishes is the electric eel. It can discharge up to 650 volts—enough to kill a person on contact. (The electric current we use in houses is usually only 120 volts.)
Electric eels live in the shallow, muddy waters of the Amazon and Orinoco rivers of South America. They are not related to other kinds of eels and resemble them only in their snakelike shape. The electric eel has no dorsal (back) or tail fins, as other fish do. It swims with the aid of a long anal fin, which runs nearly the whole length of the underside of its body. It can swim backward and forward, up and down, with equal ease. But most of the time it lives a lazy, sluggish life. It does not have to work hard to protect itself and catch its food.
The electric eel is like a living storage battery. All of its normal body organs are crowded into the front fifth of its body. The remaining four-fifths is packed with more than 5,000 tiny electric generators.
The electric eel uses its electricity in several ways. When it swims, a small "battery" in its tail sends out weak electric pulses at a rate of 20 to 50 a second. The eel uses these electric pulses to find its way. They bounce off objects and come back to special pits in the eel's head. The eel uses electric "echoes" in much the same way that bats and whale sharks use sound to find their way around. (It is fortunate that the electric eel has this ability to navigate by electricity. As it grows older, its eyes are damaged by electricity, and it becomes blind. Actually, eyesight is not too useful anyway, in the dark and muddy waters in which the eel lives.) Scientists think that the electric eel may also use its weak electric pulses to communicate with other eels.
If an enemy threatens the electric eel, or a frog or some other possible prey is in the water nearby, the eel acts promptly. It turns on the powerful "main battery" that fills most of its body. Discharges lasting about 0.002 second are sent out in quick succession. An electric eel can continue discharging at a rate of up to 150 pulses a second without showing any signs of getting tired. Fishes and frogs are killed by the eel's strong electric shocks. A larger animal—even a horse that has come down to the water to drink—may be stunned and drown. But except for the gradual damage to its eyes, the eel does not seem to be affected by the electricity at all. In fact, other electric eels are often attracted to an area where one of their species is discharging. They flock to join in the feast.
The breeding of electric eels is still a mystery. During the rainy season of the year, they disappear from their usual homes. Perhaps they go to the flooded swamplands. When they return, small baby eels are swimming along with them. The young electric eels produce very little electricity. The larger they grow, the more powerful their electric shocks become. A full-grown electric eel is one creature you want to stay away from!
1 inch = 2.5 centimeters
5 or 6 inches = 12.7 or 15.2 centimeters
The Fastest Animal
THE SPINE-TAILED SWIFT
Nature's champion speedster has only two legs and cannot run at all. Indeed, its short legs are so weak that it can hardly walk and rarely lands on the ground if it can help it. But it more than makes up for its weak legs with a pair of large, flat wings, powered by strong flight muscles. Most experts believe that the fastest living creature is a bird, the spine-tailed swift. The fastest flight that has ever been clocked took place in the USSR. There, a spine- tailed swift was seen flying at over 106 miles an hour.
The fastest of the spine-tailed swifts live in Asia. But there are other species living over much of the world, and some of them are also extremely fast fliers. The spine-tails that live in Brazil often dive straight down like missiles into the jungle ravines. Brazilians call these swifts "rockets." The spine-tailed swifts that breed in the eastern United States are called chimney swifts because they build their nests inside chimneys. Like most of the other spine- tails, these swifts used to nest inside hollow trees. But when settlers moved in and built cabins and houses, the swifts found the man-made hollows more convenient.
Spine-tailed swifts do their courtings in flight and mate high up in the air. Then the pair go looking for a good nesting place in a hollow tree or a large chimney. Off they fly to get building materials. They tear off dead twigs from tree branches without missing a wingbeat and carry them back in their bills to the nest. Each twig is carefully cemented into place with a bit of saliva from the bird's mouth. Within minutes after the saliva has been exposed to the air, it becomes hard and firm. Gradually a bowl-shaped nest is built, glued to the wall of the hollow. Before the nest is even finished, the female swift lays several longish white eggs. She and her mate take turns sitting on the eggs for nearly three weeks. Then both work to feed and care for the young chicks.
After two weeks or so, the young swifts are out of the nest, exploring the hollow. Like their parents, they cling to the wall with their sharp claws. When their feathers have grown out, they use their spine-shaped tail feathers as a prop to help support them. After about a month, they take their first flights out of the nest.
The speed of the spine-tailed swift helps it to catch meals. It snaps up insects as they fly, high up in the air. Often the swifts feed at such great heights that people on the ground can't even see them.
106 miles = 170.5 kilometers
The Slowest Animal
When something is happening very slowly, we sometimes say it is going "at a snail's pace." How fast does a snail go? It takes a lot of patience to find out. Snail watchers have found that garden snails at their speediest can cover as much as 55 yards in an hour, or about 0.03 mile per hour. But some snails creep along at less than two feet an hour—0.00036 mile per hour! The tortoise, another noted slowpoke, is a real speedster in comparison—when it's hungry, it can cover 5 yards in a minute (0.17 mile per hour). In snail races, a good winning time is 2 feet in 3 minutes. (The best human racers can run a mile in less than 4 minutes. A racing snail would take five and a half days to cover a mile.)
Of course, a race between a snail and a human would not only be silly, but unfair. The snail has only one foot, which is also the bottom of its body. (Snails belong to a group of animals called gastropods, which means "belly- foot.") A land snail moves by contracting the muscles in the sole of its foot, one after another, in a rippling wave that moves forward along the foot. The animal glides along smoothly on a carpet of wet, slippery slime that it dribbles out from an opening just under its mouth. After the snail has passed, shiny trails of slime mark its path.
A moving snail also has a heavy load to carry—you would move slowly too, if you had to carry your house on your back! The snail's soft body is covered by a hard, coiled shell. When danger threatens—perhaps a rat, a duck, a blackbird, or a human being—the snail can pull all of its body into the shell, so that the sole of its foot neatly plugs the opening. It also retreats into its shell in the hot, dry summers and in the cold winters, sealing the edges of the opening with slime. Snails can stay inactive this way, without eating or moving, for months or even years.
A snail is a funny sight as it comes out of its shell. First the "belly-foot" comes out. Then, at the front end of this soft belly-foot, two pairs of tentacles begin to poke out, as if someone were pushing out the fingers of a glove that was inside-out. When they are all the way out, the tentacles look like horns on the top and front of the snail's head. At the tip of each of the two larger tentacles is an eye. Imagine having your eyes up on stilts! The snail can look around by moving its tentacles, without having to turn its head.
Garden snails eat mainly leaves and fruit. They saw off pieces of food with a long tongue called a radula. A snail has teeth on its tongue—15,000 of them!—and it uses its tongue like a file. Garden snails can find their way back to their favorite feeding places, even if a gardener has thrown them away over a wall. They may be slow, but they get there.
Excerpted from Nature's Champions by Alvin Silverstein, Virginia Silverstein, Jean Zallinger. Copyright © 1980 Alvin and Virginia Silverstein. Excerpted by permission of Dover Publications, Inc..
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