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Scott Foresman Reading Street 5.6.1

GenreComprehension

Skills and StrategyText Features

Nonfi ction • Draw Conclusions

• Main Idea and Details

• Important Ideas

• Captions

• Headings

• Map

• Glossary

by Meish Goldish

ISBN-13:ISBN-10:

978-0-328-52542-30-328-52542-1

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by Meish Goldish

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Wolves and HumansFor thousands of years, humans have had a deep-

seated fear of wolves. They regard them as dangerous creatures that threaten the lives of both people and other animals. As far back as 7,000 years ago, farmers were killing wolves in order to protect their sheep and cattle. Even today, many children are raised with stories that warn against the “big bad wolf.”

Scientists estimate that about 250,000 wolves roamed free in North America when Europeans arrived in the 1600s. The wolves’ freedom, however, did not last long. Many settlers became farmers, and they feared the animals would kill their sheep, cattle, and other livestock. The truth, however, was that wolves only looked to attack livestock after the disappearance of their own prey.

When settlers began building their farms, they cut down large areas of forest to create space for their crop fields. With the loss of trees, many of the animals that wolves normally preyed upon lost their habitats. Since these animals no longer had a place to live and little or nothing to eat, they soon left, leaving the wolves with nothing for food but the farmers’ livestock.

People across North America began to eliminate the wolves through hunting, trapping, and poisoning. By the late 1800s, wolves had all but disappeared in most parts of the United States. In the west, hunting was especially heavy around Yellowstone National Park. By 1926 not a single wolf was to be found in the entire the park.

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Yellowstone National ParkYellowstone National Park is a vast area of land

that stretches over two million acres. Most of the park is in northwest Wyoming, but parts of it spill over into Idaho and Montana. In order to preserve the beauty of Yellowstone, the U.S. government declared the area to be a national park in 1872. It became the first national park in the world.

Yellowstone is famous for its natural wonders, such as hot springs, lakes, canyons, geysers, and waterfalls. Its forests contain beautiful trees and plants. The park is also home to many kinds of animals, including bear, elk, deer, and bison.

Today it is against the law to hunt in any national park. In 1872, however, visitors to Yellowstone were given permission to hunt. They killed predators in the park that threatened the safety of the elk, deer, and other animals there. They hunted one predator in particular—the wolf. In fact, at one time, hunters were actually paid to kill wolves inside the park in order to protect the other animals.

Hunters thought they were doing the park a favor by wiping out the wolves of Yellowstone. The wolves were at the top of the food chain, eating any animal weaker than themselves to survive. They were rarely attacked themselves because of their strength and hunting prowess. The wolves preyed on herbivores, such as elk and deer, that merely ate plants and caused no harm—or so it seemed. Therefore, how could the hunting and killing of wolves be a bad thing?

The absence of wolves, however, had an effect that no one at the time predicted. Without the top predators around, the elk and deer in the park experienced a dramatic increase in their population. Soon, Yellowstone had more plant-eating animals than its vegetation could support. The herbivores had to compete for food.

Yellowstone National Park is famous for its natural beauty.

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The absence of wolves at Yellowstone had another negative effect. A new predator—the coyote—rose to the top of the food chain. Rather than deer and elk, most coyotes in the park preyed on ground squirrels and other small rodents. With the increase in coyotes, smaller predators, such as foxes and owls, began to find difficulty in catching enough food to eat. Some of the foxes and owls began to starve and eventually grew sick or died.

Some coyotes at Yellowstone also preyed on larger animals, such as fawns, or baby deer. In a short span of time, the coyotes killed so many fawns that park officials worried about the future of the entire deer population in the park.

With no wolves at Yellowstone, coyotes rose to the top of the food chain.

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The absence of wolves at Yellowstone did not affect only the food chains of larger animals. It also had an impact on the park’s vegetation. This, in turn, had far-reaching effects on numerous other ecosystems throughout the park.

For example, the overpopulation of elk relentlessly gnawed on the bark and shoots of aspen trees, cottonwood trees, and willow bushes. As a result, new tree and bush growth came to a rather abrupt halt. This affected animals that relied on the trees and bushes that served as their habitats. For instance, songbirds had fewer places to nest, causing many of them to disappear from the area altogether.

Without wolves to chase them, more elk had time to feast on the trees and bushes, many of which stopped growing.

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With the halt of new tree and bush growth, beavers in the park also suffered. They fed on aspen trees and stored its wood for their food supply during the winters. Throughout the year, they also used the trees to construct homes and dams. Their dams created ponds that became homes for other park creatures, including ducks, moose, and dragonflies, as well as general pond life such as fish, frogs, and algae. But with fewer trees, many beavers and other park creatures went hungry and became homeless or died.

A New View of WolvesIt took scientists many years to come to the

realization that the absence of wolves at Yellowstone was hurting the animals and plants that remained there. One of the first scientists to discover the problem was Aldo Leopold. He began his career as a forest ranger in the southwestern part of the United States, and during his first years on the job, he thought—like everybody else—that killing wolves was good for the environment.

Wolves usually attack only sick and old animals, and leave the strong, healthy ones alone.

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Later, however, Leopold changed his mind about and attitude towards the dreaded predators. He knew that other scientists had been studying wolves around the country. Those scientists concluded that wolves were a valuable part of their ecosystems. They claimed that the wolves, rather than causing harm, were actually helping their environments by preying on other animals.

How could wolves help by killing other animals? The answer was simple and logical. Scientists found that wolves mostly preyed on old and sick creatures in general because they were easier to chase and kill. This natural population control measure, in turn, left more food available for the remaining healthy elk. Over time, this produced a stronger elk population that could better endure greater hardships, such as lean winter months or even diseases.

After conducting studies of his own, Leopold came to the same conclusion as the other scientists. He now strongly believed that wolves, as predators, were positive, not negative, contributions to an ecosystem. Leopold needed a forum to prove to others that his idea was correct. In 1944 he became the first scientist to suggest that wolves be brought back to Yellowstone National Park.

Aldo Leopold

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An Uphill BattleEven though Aldo Leopold was a well-respected

scientist, not everyone agreed with his idea to repopulate Yellowstone with wolves. Some scientists felt that more research on predators and their impact on an ecosystem was necessary. Additional studies were conducted. By 1972 the results had convinced more scientists that returning wolves to Yellowstone was a wise decision. Yellowstone was chosen as a testing ground because its ecosystem only lacked one species—wolves.

However, another group of people strongly objected to the plan. The many ranch owners in the western United States feared that bringing wolves back into Yellowstone would pose a serious threat to their sheep, cattle, and other livestock.

Government officials found themselves in a dilemma. They wanted to return wolves to

Ranchers feared that wolves in Yellowstone would roam outside the park and attack their animals.

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Yellowstone; yet many of the ranchers who objected to the idea were apart of a powerful group who managed to persuade many members of Congress that wolves did not belong in the park.

In 1973 the wolves received some new support. Congress passed a new law called the Endangered Species Act. It was created to protect the plants and animals—including wolves—in danger of becoming extinct in the United States. Under this act, harmful activities, including hunting, capturing, or collecting endangered animals, were made illegal. The law set a $10,000 fine on top of jail time for any person found guilty of killing a wolf.

Even with this new law, ranchers in the West battled to block the return of wolves to Yellowstone. They threatened to shoot and kill any wolf that attacked their livestock. Clearly, the government had to find a way to win over the protestors and put their fears to rest.

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A biologist named Renee Askins came to the aid of the government. An avid wolf supporter, she began a campaign in 1981 to win over the ranchers who adamantly objected to the Yellowstone plan. She traveled throughout the west, speaking to groups of ranchers, explaining that wolves in balanced ecosystems actually killed very few cows and sheep.

Additional help came from an organization that protected wildlife. They raised money in order to reimburse any ranchers for livestock that might be lost to wolves. Even so, some ranchers still objected to the plan.

Finally, the government agreed that ranchers would be allowed to shoot and kill any Yellowstone wolves that attacked their livestock. This satisfied the ranchers, and by 1994—more than a dozen years after Askins began her campaign—many of the ranchers who had objected to the Yellowstone wolf plan were now willing to accept it.

Renee Askins

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The Wolves ReturnIn late 1994, government officials were ready to

reintroduce wolves to Yellowstone. The program was called the Yellowstone Wolf Project. Two of the scientists in charge of the project were Doug Smith and Mike Phillips.

Smith and Phillips first needed to find wolves to bring to Yellowstone. They traveled to Canada and captured 14 gray wolves there. After a careful health inspection, they were flown to Montana.

In January 1995, the wolves were brought into the park. It was the first time in nearly 70 years that wolves had been inside Yellowstone. The scientists were eager to release the animals, but it was vital that they place radio collars around the wolves’ necks so they could track the animals’ movements once they were set free. Then, they divided the wolves into three separate groups, called packs.

Doug Smith checks a radio collar used to track the wolf in the park.

Now Smith and Phillips had to make a choice. Should they simply let the wolves run free in the park, or should they keep them in holding pens for a while? They decided to keep the wolves in pens for ten weeks before releasing them.

The scientists chose to pen the wolves for several reasons. First, they hoped that the animals in each pack would bond with one another while inside their pen. That way, the wolves would be more likely to stay together once they were set free. Also, being penned, the wolves had time to adjust to their new surroundings. Smith and Phillips wanted the animals to stay inside the park after being released rather than trying to make their way back to Canada.

Smith and Phillips were especially concerned about two of the wolves in each pack. These were the alpha male and alpha female. Alpha wolves are the leaders of a pack and usually the only ones in the group to mate.

One pack was named Rose Creek. Its alpha female was called Number Nine, and the alpha male was Number Ten. The scientists hoped that these two wolves, once released, would produce baby wolves, or pups. Yet no one could be sure that the two adult animals would even get along with each other.

After ten weeks in their holding pens, the wolves in all three packs were released into the park. Smith and Phillips tracked their movements using the signals sent out by the radio collars.

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Number Ten

Number Nine

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Smith and Phillips tracked the wolves by airplane. They were thrilled to discover that Number Nine and Number Ten were staying together. However, these two alpha wolves eventually roamed outside the boundaries of the park. They settled near a small Montana town outside of Yellowstone.

Then tragedy struck just one month after the wolves’ release. Number Ten, the male alpha, was shot and killed by a hunter. Smith and Phillips worried that Number Ten had not mated with Number Nine before his death.

Scientists searched for Number Nine, the alpha female. A week later, they found her. To their delight, they also found eight wolf pups that Number Nine and Number Ten had produced! Smith and Phillips now knew that the wolves could produce babies in their new environment. The future for the wolves looked bright!

Number Ten fathered eight pups before he was killed.1974 1981

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Smith and Phillips were so pleased by the success of the first wolves at Yellowstone that they released 17 more wolves into the park the following year. Those wolves, as the ones before them, managed to survive in the park.

Over the years, the wolves at Yellowstone gave birth many times and increased in number. The young pups grew up and formed new wolf packs of their own. Today, about 170 wolves roam throughout Yellowstone in more than ten packs.

As Renee Askins promised ranchers years earlier, the Yellowstone wolves kill very few cows or sheep. Instead, the wolves hunt mostly elk and deer inside the park. Also as promised, ranchers have been reimbursed for any animals they lost to the wolves.

Range of gray wolves in the United States mainland, in 1974 and 1981

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Changes in the ParkThe wolves have returned to Yellowstone. They are

the top predators again, just as they were before their disappearance in 1926. Their return to Yellowstone has greatly affected the park’s animal and plant life. Yet have these effects been good or bad for the ecosystem?

The return of the wolves has improved the park in many ways. First, the wolves have killed or chased away the coyotes that were hoarding the prey that might have been eaten by foxes and owls, whose numbers, in turn, have increased. The absence of coyotes has also benefited the deer population. Without coyotes to hunt and kill them, more of the fawns now manage to survive.

An additional improvement to the park’s ecosystem with the return of the wolves is their

The return of Yellowstone’s top predator—the wolf—has helped other animals in the park find food.

impact on other large hunters and foragers at Yellowstone. Periodically after wolves make a kill and don’t eat their entire prey, bears come and feast on the remaining meat, along with other meat eaters such as eagles, ravens, and even coyotes. As the top predators, the wolves actually provide more food for other park animals.

Another major benefit for the ecosystem is the return of native vegetation. After the wolves vanished, too many elk and deer lived off the limited plant resources. These animals became so hungry that they had to eat the shoots and bark of aspen trees, cottonwood trees, and willow bushes, which stopped reproducing as a result. But, with the wolves’ return, more trees are growing, providing young and healthy animals with more food to eat.

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The increase in trees and plants at Yellowstone has also been good news for the beavers. Once again they have an abundance of aspen trees to eat and to store for the winter. They have the wood to build homes and dams. The new dams have created new ponds where ducks, moose, and dragonflies, as well as fish, frogs, and algae, can once again make their homes.

Finally, the increase in trees has resulted in an increase in the number of homes for animals that benefit from their shelter. Songbirds can once again build nests in the aspen trees, and owls can perch on them during their hunt.

All of these positive changes have been the direct result of the return of wolves to Yellowstone. They have completed the ecosystem and improved the balance between animals and plants.

Today there are many more groups of beavers in Yellowstone as a result of the increased number of trees there.

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ConclusionThe Yellowstone Wolf Project has been a great

success so far. Scientists expect that it will continue its success in the future.

The return of the wolves to Yellowstone taught some important lessons. The wolves proved that they are not the looming threat that society once made them out to be. Wolves kill to survive, but their killing is not bad or evil. In fact, they demonstrated their value in our ecosystem. Though few in number, as top predators they affected the health of an ecosystem more heavily than another animal, greater in number, might have.

Thanks to the wolves, scientists also learned a valuable lesson about the interconnectedness of all living things. By studying the ecosystem at Yellowstone, it becomes easy for us to see how our actions affect other living things.

Scientists began to realize that wolves existed for a reason. Different species of wildlife help each other maintain healthy populations. The fact that wolves kill other animals is not the problem. Problems only arise when humans begin to interfere with this natural balance of life.

Changes to natural environments may seem small, but as we’ve learned, their effects can be far-reaching.

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Where Did All the Cows Go, Anyway?Imagine a world in which something bizarre has

happened—animals that we normally see around have disappeared. But not just one here or there has disappeared —rather, an entire species no longer exists! Which animal are you picturing? How does the disappearance affect you? How has the loss affected the world? Work with a group of classmates to write a report. Explain how the animals’ absence has changed life on Earth.

Wh Did All th C G A ?

Now Try This

Report

on the

Environment

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1. First, decide on the type of animal to disappear from Earth. It might be all the dogs, all the butterflies, or all the cows in your town or state or country. The choice is yours.

2. Next, discuss among your group how the loss of your animal might affect the world. How would it affect people’s daily lives or their jobs? How would it affect land and nature? How would it affect the economy? What good or bad outcomes might result from the animals’ absence?

3. Assign different members of your group to write separate parts of the report. For example, some members might write about the effects on people’s lives and jobs. Other members might write about the effects on land and nature, and so on. Ask each group’s members to include at least one visual aid, such as a map or chart, in their part of the report.

4. As a group, put your report together in the best possible order. Then, share the report through a presentation to the rest of the class.

Here’s How To Do It!

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adamantly adv. in a way that is firm and unyielding

dramatic adj. impressive

foragers n. animals that hunt or search about for food

forum n. a meeting where questions or ideas of public interest are exchanged

hoarding v. to save and hide or store away for future use

logical adj. reasonable; having sound sense

measure n. a reasonable boundary or limit that should not be exceeded

prowess n. unusual skill or ability

reimburse v. to pay back with money

relentlessly adv. in a way that is unyielding; without stopping

adamantly adv. in a way logical adj. reasonable;

Glossary Reader Response1. What conclusions did you draw about the effect

of the loss of wolves to Yellowstone National Park? What did you conclude about ecosystems from reading this book?

2. Using a chart like the one below, write down important ideas that you learned from what you read. Why are they important? How does this help you better understand the book?

Important Idea Why is this important to know?

3. Write down the definition of measure in the context from which you normally read it. Use the word twice in a sentence that uses both the definition from this book and your definition. For example, Lori placed the section of the tree trunk into the trunk of her car.

4. If you were a rancher living outside Yellowstone today, how would you feel about the wolves? Give reasons for your answer.

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