Happy Fossil Day! Fossils are the remains of a once-living creature, either animal or plant. However, there are two different types of fossils. Body fossils are leftover parts of the organism. These could include the bones, teeth, or eggs of an animal, or the leaves or bark of a plant. Trace fossils, on the other hand, are things or impressions made or left behind by an organism. They can show evidence of the organism´s behavior rather than it´s physical body. These could include footprints or waste. Would a claw be a body or a trace fossil? What about a nest?