<p>Endangered Species</p><p>Until a few hundred years ago, species became scarce or died out because of natural causes. For example, there may have been a major climate change. Today, however, species become endangered mostly because of human activity. The main reasons are habitat destruction, wildlife trade, overhunting, and competition with domestic animals and animals brought into their habitat from elsewhere.</p><p>Habitat destruction is the most serious problem for species in the wild. Most animals and plants can live only in a certain area, or habitat. If their habitat is destroyed, the species cannot survive.</p><p>People destroy plant and animal habitats in many ways. They cut down forests to build houses or make room for farmland. They graze their livestock in the grasslands used by wild animals. Their livestock eat too much grass, and the grass doesn't have a chance to grow back. Wetlands and swamps along seacoasts are being filled in with land. Then people build new housing on them.</p><p>Tropical rain forests have more species of plants and animals than any other area on Earth. But the rain forests are being destroyed faster than any other wild habitat. Some scientists say that all the rain forests could soon be gone unless they are protected.</p><p>Wildlife trade is another problem. Animals are caught in the wild and sold to zoos or as pets. Some are used for medical experiments. Animals are killed for their fur or other body parts.</p><p>In many countries, laws have been passed against hunting animals. But some people hunt anyway. They are called poachers.</p><p>Overhunting also puts animal species in danger when hunters kill too many of one kind of animal. The animals cannot give birth to enough new babies to make up for those that have been killed. Animals that have been overhunted include the Caribbean manatee, the Asiatic lion, and many species of pheasant.</p><p>Competition with domestic and nonnative animals is another problem that has occurred on many islands. Domestic cats may eat birds and small mammals. Sometimes rats leave ships when they come into the harbor. Then the rats spread over the island. And they kill small birds and eat their eggs.</p><p>Protecting endangered species</p><p>Many people are very concerned about protecting plants and animals in the wild. Today, there are many ways we can help keep these species alive. Nations today pass laws to protect endangered species. In the United States, the Endangered Species Act of 1973 protects endangered wildlife against anything that harms them or their habitats. Also, many wild species are protected by CITES—the Convention on International Trade in Endangered Species of Wild Fauna and Flora (“fauna and flora” means animals and plants). This agreement forbids the trade of furs and live animals of endangered species.</p><p>Some laws stop people from hunting too many of one kind of animal. Some of these laws forbid all hunting of certain animals. Other laws allow hunters to kill only a certain number of animals. And there are laws that protect plants from being taken from the wild.</p><p>Some animal species that are now extinct in the wild still live in zoos. They live in animal research centers, too. Scientists at these zoos and research centers try to help these animals start new families. They hope that someday these new families can return to the wild.</p><p>Rare plants are saved by being grown in large gardens called botanical gardens. The seeds are saved in special seed banks for future planting.</p>