The shape, or morphology, of the gut makes a huge difference in what an animal can eat and digest. But gut diagrams are only available for a handful of species – and we have no idea how much one individual varies from another. We are especially interested in the cecum, a pouch that aids in digestion. In mammals and birds, the cecum is located between the small intestine and the large intestine (or colon), and is filled with microbes that help digest fiber. In fish, the cecum is located between the stomach and the intestine. Instead of providing a home for fiber-digesting microbes, the fish cecum provides extra space and time for food to be digested more thoroughly. Mammals have 1 cecum (or none at all). Birds typically have 2 (“twin”) ceca. Fish exhibit the most variation: each cecum is made up of separate pouches, which may be stubby (“nubs”) or long (“finger-like”) extensions. But many fish have no cecum at all. Here's where you come in: By taking pictures of the guts of each animal you harvest, you can help us map the unknown guts of wildlife. We will use software to measure the length of each cecum, and to compare the differences between individuals and across species.