Who were the first humans to reach North America? When and how did they arrive? Noted author David L. Harrison explores the various theories of North America's first people: Some evidence suggests that they walked across the land bridge that once connected Siberia and Alaska. Elsewhere, a growing number of archaeologists believe that at least some, if not most, of our forefathers arrived by boat along North America's northwest coast, possibly from Southeast Asia or Japan. Other archeologists speculate that humans reached the continent by boat, crossing the frigid North Atlantic waters from Europe. With archeological field photographs and realistic illustrations by Richard Hilliard, the author demonstrates how scientists are like detectives, investigating mysteries that took place more than one hundred centuries ago. Includes maps, glossary, sources, index.

Reveals new information about the mammoth elephant, and about the science that grew up around its discovery.

This title describes a walk with a dinosaur, as two teams of scientists race to bring back to life the long-extinct woolly mammoth, using DNA from a frozen mammoth discovered in a cliff face in Northern Siberia. Advances in medical and scientific technology mean that the impossible is now theoretically possible: a mammoth can be cloned from a frozen, long-dead mammoth corpse. But it's not easy. No one knows for sure how long frozen mammoth sperm keeps. Elephant sperm keeps well, but the mammoth has been extinct for at least 4000 years. But the mammoth remains a vividly real image: huge, with great curving tusks it is both utterly familiar and completely unknown.

Presents information on mammoths, and discusses the mysteries that are unlocked from the fossils and mummies that are discovered.

Contains expert information on the natural history and characteristics of mammoths, telling where and how they lived, what they ate and why they died. Includes information on the latest research and fossil discoveries around the world.