Tertiary consumers are organisms that occupy the third level in a food chain. They primarily eat secondary consumers, which are typically carnivores or omnivores. Tertiary consumers play a crucial role in maintaining the balance of ecosystems by controlling the populations of secondary consumers. Examples of tertiary consumers include large predators like lions, eagles, and sharks. These animals are often at the top of the food chain, meaning they have few or no natural enemies. Their presence helps regulate the populations of other species, ensuring a healthy and balanced ecosystem.