Defining Animal Diets by Food Source
The primary difference between a herbivore, carnivore, and omnivore is what they eat. Herbivores are animals whose diet consists exclusively of plant matter. Carnivores primarily eat other animals (meat). Omnivores have a diet that includes both plants and animals.
Examples in the Animal Kingdom
A simple way to understand these categories is through examples. A deer, which eats only grass and leaves, is a herbivore. A tiger, which hunts other animals for food, is a carnivore. A grizzly bear, which eats both fish and berries, is an omnivore.