This document classifies heterotrophs into five categories: herbivores, carnivores, omnivores, saprophytes, and parasites. Herbivores like deer, cows and rabbits eat plants. Carnivores such as tigers, wolves and lions eat other animals. Omnivores including humans, cats and dogs eat both plants and animals. Saprophytes like fungi, bacteria and mushrooms feed on dead and decaying matter. Parasites such as hookworms, tapeworms and mistletoe plants live in or on another organism and get nutrients from it.