Sonar is a technique that uses sound propagation (usually underwater) to navigate, communicate or to detect other vessels. Sonar may be used as a means of acoustic location. The term sonar is also used for the equipment used to generate and receive the sound. The frequencies used in sonar systems vary from infrasonic to ultrasonic.
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 meters and 40 kilograms, up to 9.5 m and 10 ton. They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid. Dolphins are considered to be amongst the most intelligent of animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture.
3, Native Americans
Native Americans were living in North America for many hundreds of years before Europeans reached the continent. For a long time white people called them Indians (see in picture).
Today, many people do not like this name since it is based on a mistake: it was given to the people living in the Americas by Christopher Columbus who, when he arrived there, thought he had discovered India. Instead, people prefer to use the term Native Americans. There are also native people living in Alaska and Canada, e.g. Inuits (see in picture—an Inuit in kayak) and Aleuts, but they are separate groups and are not called Native Americans.
Early contact with Europeans
In Pre-Columbian North America there were many tribes who lived by hunting animals and gathering plants. Many of the tribes moved from one place to another according to the season and what food was available. Most of what is known about Native Americans dates from the time when they came into contact with Europeans.
The first place in the US where Europeans settled permanently was Jamestown, Virginia, founded in 1607. At first Native Americans were positive about the Europeans and were happy to have the many new things they brought, e.g. metal cooking pots, cloth and guns. But the Europeans also introduced diseases that Native Americans had no resistance to, so many became ill and died. They also brought alcohol, the effects of which Native Americans did not know. Some Europeans took advantage of this by getting them drunk and then paying low prices for their goods.
The worst problem for Native Americans, which lasted into the late 20th century, was that the new settlers wanted their land. To Native Americans owning land was a strange idea. Tribes moved around as they pleased and shared land with any other tribe that was friendly. They did not understand that a person might believe a piece of land was theirs, or that they would try to keep others from using it. The settlers, on the other hand, assumed that they would take control of North America and used all means to do this, including making agreements, which they usually did not keep, tricking Native Americans into selling land cheaply, and taking it by military force. Native American chiefs like Sitting Bull, Tecumesh and Geronimo fought against the settlers.
As Whites began moving west, Native American tribes had to be moved on. Some were forced to go to other parts of North America, to areas very different from the ones they were used to. The Trail of Tears was one of many terrible examples: in the cold winter of 1838-1839 17000 Cherokees had to move from their land in the south-east to what is now Oklahoma and more than 4000 died. The government promised tribes that if they agreed to stay in one part of the country they could keep that land forever. But the promises lasted only until Americans discovered that the land they had given them was good for farming or had gold.
Whites have explained this behavior in different ways. When the Indians fought and killed white people they said that this proved that Native Americans were wild and had to be controlled. People also believed that the Native Americans were wasting good land by not developing it. In the 19th century Americans believed in manifest destiny, meaning that they thought God wanted them to occupy the whole continent. They also believed that it was better for the Native Americans to learn to live like white people and tried to teach them Christianity. Many Native American children, including the athlete Jim Thorpe, were taken away from their tribe and sent to schools where they were not allowed to speak their own language.
Native American languages
Before Europeans arrived in North America there were over 300 Native American languages. Some have now died out, and of the 250 or so remaining many are spoken only by a few older people. Other languages, like Cherokee, are more widely spoken. Most Native Americans speak English, some as their first language and others as their second.
Native American languages have added many words to English, though the meaning of a word has often been changed. Teepees are a kind of tent, wampum belts were made of beads and since the belts had great value Europeans used wampum to mean ‘money’. Moccasins, a kind of shoe, are today worn by people all over the world. Many Native American words describe the things they name. For example, the Asakiwaki tribe’s name means ‘people of the yellow earth’, and the Cherokees’ name for themselves, Ani-Yun’wiya, means ‘the leading people’. Indian names for Whites included ‘people greedily grasping for land’.
Many American place names have their roots in Native American languages. Ohio, for instance, is a Native American name, and the names of many of its towns and cities, such as Chillicothe and Sandusky, and the lakes Scioto and Olentangy, are of Native American origin.
Native Americans today
According to the Bureau of Indian Affairs, a part of the US government, there are now about 550 tribes. These include well-known groups like the Navajo and Sioux, and less famous tribes like the Cayuse. The number of Native Americans living in the US is about 1.2 million.
Almost a million live on reservations (see in picture—an Indian reservation in New Mexico), areas of land that the government has allowed them to keep as their own. Native Americans are US citizens, and have the rights and responsibilities of any US citizen. However, reservations have their own governments and police forces and Native Americans pay different taxes. They also have the right to hunt and fish where and when they like, while other Americans have to get a license.
On or off the reservations Native Americans find it difficult to live the traditional life. Activities of other Americans affect the way they live. Building dams across a river, for example, can affect the numbers of fish living there, so that even though Native Americans have the right to fish they may not be able to catch anything. Away from the reservations, many Native Americans find that their culture is very different from that of white people and have difficulty adapting.
Poverty is a serious problem. About 37% of people who live on reservations are unemployed, compared with 6% of the general population. Many tribes try to bring in money from outside. Some sell rights to search for oil on their reservation; others use the fact that the reservation makes its own rules to open casinos where people from outside can come and gamble. Gambling is illegal in most parts of the US and many Americans want it to remain so, but it makes a lot of money for the tribes. This brings Native Americans, once again, into conflict with white Americans.
Native Americans in the popular imagination
An American tradition dating back to early times is Thanksgiving. When the English arrived in Jamestown many died during the long cold winter, but in the following spring Native Americans showed them what local foods they could eat. In the autumn, well-prepared for the winter, settlers and Native Americans had a special dinner together, the first Thanksgiving, to thank God and the Native Americans for all the food they had.
Another story describes how the Native American princess Pocahontas saved the life of John Smith, the leader in Jamestown, when her father, Powhatan, wanted to kill him. She later married another Englishman, John Rolfe, and went to England with him. The story of Pocahontas is widely known and many Native Americans are proud to have her as an ancestor.
But Native Americans were more often seen by white settlers as the enemy. Westerns, i.e. films and books about the Wild West, use the threat from Indians as their central theme. In this context Native Americans are still called ‘Indians’. Children often play ‘cowboys and Indians’ and pretend to kill each other. When Buffalo Bill, began touring the US with his Wild West show, the chief Sitting Bull was one of many Native Americans in it, and many people went to see this former great enemy.
Many Americans have an image of a ‘typical Indian’, a chief (see in picture) who lived in a teepee with his squaw (=wife), smoked a peace pipe after signing a treaty with the white man (whom he called pale face), sent smoke signals to communicate with people far away, and spoke broken English full of colorful expressions such as ‘big heap wampum’ (a lot of money) and ‘speaks with forked tongue’ (is lying). Most of these ideas have some basis in Native American culture, but it is wrong to put them all together and believe that that was how Native Americans lived.
Americans make such mistakes because they have little interest in Native Americans. Having succeeded in pushing them out of the way onto reservations, most Americans ignore them. This may be because the Native Americans who are left are living proof of a hard truth: America wants to be, and often is, a land where everyone has a chance and where the government behaves fairly and honestly to all, but this America is built on land stolen from the people who lived there first.
美洲原住民的语言为英语增加了许多词汇，但词义往往有所变化。Teepee 是一种帐篷，贝克数珠腰带由贝壳串的珠子做成。由于这种腰带很值钱，欧洲人用wampum来指“钱”。Moccasins是一种鞋，现在世界各地的人都在穿。美洲原住民的许多词汇形象地描述他们命名的对象。例如，Asakiwaki部落的名字意为“黄土地上的人”，彻罗基人给自己起名Ani-Yun’ wiya,意思是“领导者”。印第安人给白人起的名字里包括“贪婪攫取土地者”。
许多美国人心目中有“典型的印第安人”形象：一个与妻子一起住在帐篷里的酋长，在同白人签订条约以后抽着和平烟斗，发出烟雾信号与远方的人联络，说着蹩脚但生动的英语，例如 big heap wampum（很多钱）和 speak with forked tongue（说谎）。美国人的这些想法大多源于美洲原住民的文化，但把这些拼凑起来，认为这就是美洲原住民的生活，那就是错误的。