Hamster poop (feces) serves several purposes: 1. Nutrient Absorption: Hamsters eat their own poop (coprophagy) to re-absorb essential nutrients, such as vitamins B12, biotin, and K, as well as proteins, fibers, calcium, phosphorus, potassium, and magnesium. 2. Territorial Marking: Hamsters use their poop to mark their territory, leaving a scent that helps them communicate with other hamsters and establish boundaries. 3. Waste Management: By consuming their poop, hamsters help keep their living space clean and prevent the buildup of waste, which can attract predators in the wild. 4. Stress Relief: Hamsters may eat more poop when they are bored or stressed, which can be a self-soothing behavior.