266 climate and geography: The Americas The Appalachian Mountains stretch from what is now eastern Canada down to northern Georgia They are fairly low, gentle mountains and in ancient times were heavily forested with many different species of trees They also had a large population of wild animals, both carnivores and herbivores They form a physical barrier between the eastern and western portions of the region; walking through them was difficult, though by no means impossible The highest mountain in the chain is Mount Mitchell in North Carolina The higher elevations have colder temperatures than the lowlands to the east and west The southern coast of what is now the United States lies along the Gulf of Mexico This region has fertile soil and warm temperatures, though it has always been prone to hurricanes in the late summer and autumn In fact, researchers have found that hurricanes struck the Gulf Coast much more frequently between 1500 b.c.e and 1000 c.e than they today The region was heavily forested in ancient times, and the forests were full of wild game animals The Gulf of Mexico itself supported many fish and shellfish The gulf has gentler tidal patterns than the larger oceans and is more easily navigated in small boats CARIBBEAN The Caribbean region lies to the southeast of North America and north of modern Venezuela in South America It consists of an arc of islands that run from the Bahamas and Cuba in the northwest to Trinidad and Tobago in the southeast The only way to travel from island to island in ancient times was by boat People who lived on the islands tended to be very isolated from other cultures It appears that humans colonized the Caribbean from South America and moved northward The first evidence of humans on the islands was found in Trinidad, just off the coast of Venezuela, and dated to about 5000 b.c.e The journey from the mainland to Trinidad would have been very short, unlike the voyages to more distant islands, which would have required sailors to leave sight of land and navigate ocean waters The Bahamas are low, flat islands in shallow water Most of the other islands of the Caribbean have more variation in elevation Modern Cuba and Hispaniola contain a mix of hills and flat plains Puerto Rico and Jamaica are hilly, as are most of the islands in the Lesser Antilles, the chain of islands forming the eastern boundary of the Caribbean chain Many of these islands are volcanic in origin, and some of them contain volcanoes that are active to this day Eruptions and earthquakes were common occurrences in ancient times The Caribbean climate ranges from subtropical in the Bahamas to tropical in the southernmost reaches The islands supported lush vegetation and thick forests that were home to many species of animals, including some unusually small birds and snakes and other animals unique to the islands The oceans around the islands teemed with fish and shellfish Coral reefs lay just offshore of most Caribbean islands, attracting fish and other marine life to their rich habitats Hurricanes presented one of the greatest risks to people living in the islands A hurricane could completely destroy towns and kill thousands of people in a single day MEXICO AND CENTRAL AMERICA Mexico and Central America were home to several large civilizations The Olmec lived on the coast of the Gulf of Mexico between 1500 b.c.e and 400 c.e The city of Teotihuacán, near modern Mexico City, was inhabited from 150 b.c.e to 750 c.e The Mayan Empire encompassed parts of what are now Guatemala, Mexico, Honduras, and Belize, and lasted from about 1800 b.c.e to the 17th century c.e All of these civilizations supported themselves by farming, and all worshipped rain gods, a sign that they were preoccupied with receiving enough rain to nourish their crops Modern Mexico lies south of the main North American continent Two-thirds of Mexico is mountainous The Sierra Madre Occidental and the Sierra Madre Oriental are the main ranges; they run north to south and have an average elevation of 10,000 feet They were formed by volcanic activity, and many of them were active in ancient times The Pacific Ocean lies to the west and the Gulf of Mexico to the east of Mexico Mexico’s climate varies depending on altitude, latitude, and distance from the ocean Warm areas, including the coastal zones, southern Mexico, and the Yucatán, have mean temperatures of about 80 degrees Fahrenheit, though they can reach 120 degrees Fahrenheit The central region has mean temperatures of about 60 degrees Fahrenheit Rainfall is low throughout Mexico except in the southern Gulf Coast area (modern Tabasco) El Niño activities affect weather patterns on the Pacific coast, and hurricanes sometimes batter the Gulf Coast In ancient times about two-thirds of Mexico was covered with forests; numerous types of plants and animals lived there in various ecosystems Central Mexico is covered with rolling hills and valleys; the soil in the valleys is generally much more fertile than that on the hillsides Many of the hills are former volcanic cones Mexico City, the former Aztec capital, is located in the southern part of this area A wide coastal plain lies along most of Mexico’s eastern coast The Yucatán peninsula juts north into the ocean between the Gulf of Mexico and the Caribbean Sea The Yucatán is very hilly It lacks major rivers In ancient times this region was covered with seasonal tropical forests; it received rain between May and October but also experienced some dry times in the spring The region experienced periodic droughts when little rain fell for many years; these droughts seem to have occurred every 200 years or so No major rivers supplied water to the region, so the Maya had to depend on rain The Yucatán has ample freshwater underground, but this is not always accessible to humans Much of the Yuca-