Paleontologists study the record of life on Earth left as fossils. They specialize in the study of prehistoric life, particularly through the examination of fossils. Paleontologists actually study all fossilized past life, including everything from corals and shellfish to fishes and mammals. More than 99 percent of all species that have ever lived are extinct, so paleontologists will not run out of work any time soon. Most paleontologists spend a lot of time in the field to collect the fossils that they study. Field work can be done anywhere from a remote mountaintop to a local quarry. Paleontologists use a variety of techniques to analyze fossils, including microscopic examination, X-ray imaging, and chemical analysis. By studying fossils, they can reconstruct the physical and behavioral characteristics of extinct species, as well as the environments they lived in. They also use fossils to understand the patterns of evolution and extinction that have shaped life on Earth over millions of years. Paleontologists work at universities, museums, oil companies, and state and federal government agencies. Duties of paleontologists employed by museums include research, curation of collections, exhibit design, and public education. Paleontology combines biology and geology, and paleontologists need a broad scientific training. To become a paleontologist, college students need to first follow the undergraduate course of study recommended by the geology departments in their colleges and universities. Paleontology typically requires a doctorate degree in the field, especially for positions like a professor or researcher.