Consumers are those organisms that obtain energy by either consuming the food prepared by plants or by consuming other consumers of autotrophs.
In a food chain, consumers are categorized into 3 categories, namely herbivores, carnivores and omnivores. Primary consumers are herbivores. They feed on producers or plants. Examples include zebra, giraffe, cow. Secondary consumers are carnivores. They feed on primary consumers for food. Examples include lion, tiger. Omnivores are those consumers which feed on both plants (producers) and animals (primary consumers). Examples include bear, chicken.