Unearthed! Fun Facts

• People who study ancient life forms (fossils) are called "paleontologists." People who study the material culture of humans are called "archaeologists." If you study the fossils of ancient humans, you are called a "paleoanthropologist."
• Fossils are the remains of ancient life. They may be bones or teeth or even mummified or frozen remains, such as frozen mammoths found in Siberia. Or they may be traces of ancient life, such as footprints.
• So-called saber-tooth "tigers" are not related to tigers. They are properly called saber-toothed cats.
• Bison immigrated into North America about 120,000 years ago. Herds roamed Southern California during the Ice Ages.
• Bison latifrons stood more than eight and a half feet tall at the shoulder.
• The earliest ancestors of the modern horse date back 65 million years, in the Age of Dinosaurs. The earliest-known horse lived 56 million years ago.
• Horses that lived near Barstow 15 million years ago had three toes on each front foot.
• Horses disappeared from North America at the end of the Ice Ages. They were reintroduced to the continent by Spanish explorers.
• Ground sloths were protected from predators by pebble-like bones called dermal ossicles that grew inside their skin and acted like armor.
• North America and South America were separated until about 9 million years ago. Once they were connected by Central America, animals were able to migrate between the two continents.
• Mastodons and mammoths are different kinds of elephants.
• Mammoths were the largest land animals alive during the Ice Ages.
• The most common kind of mammoth in Southern California was not "wooly," but had skin much like today's African and Indian elephants.
• No one knows exactly why so many large Ice Age mammals disappeared from North America. Their extinction might relate to changes in climate, to disease, to hunting by early humans, or by a combination of factors.
• When paleontologists find a large fossil bone, they protect it with a plaster cast to protect it before it is moved, just like a doctor would put a cast on a broken arm or leg.
• Federal and state laws protect fossils as irreplaceable antiquities.
• Sometimes paleontologists can predict where fossils might be found by studying "stratigraphy" (layers of earth and rock).
• Fossils can be preserved if their bone structure is replaced by minerals: they are "petrified." But not all fossils are petrified: they may be preserved as bones in caves, or trapped like insects in amber or mammals in tar pits, or even flash-frozen like mammoths in the arctic circle.
• Animals and plants that once lived on earth are very rarely preserved as fossils. When most animals die, their bodies decay or are eaten and scattered by predators.