Invertebrate Paleontology is the study of fossil invertebrates (animals without backbones). Most groups of invertebrates and geologic ages are represented in the IMNH collection including sponges, corals, trilobites, insects, crustaceans, clams, snails, sea urchins, and sea lilies. The holdings contain 1200 catalogued specimens from the state of Idaho and the Intermountain West. We also have collections of trace fossils, including the tracks, trails and burrows of ancient organisms. Invertebrate fossils are the primary evidence for discovering the rich history of life on Earth and provide important clues to understanding the world's geology. The vast majority of animal species that ever lived are now extinct, and these forms can only be studied as fossils. Their study provides a unique window into the past and allows us to determine how life has responded to climate change throughout time.