Primary consumers are organisms that consume or feed on primary producers, which are autotrophic plants that produce their own food through photosynthesis. Primary consumers are also known as herbivores and make up the second trophic level in a food chain. They are usually small in size and there are many of them. Primary consumers can be classified into different groups based on their feeding strategies. For example, algivores feed on photosynthetic algae, frugivores feed on the fruiting bodies of plants, and folivores feed on leaf material.

Some examples of primary consumers include grasshoppers, rabbits, and deer. Primary consumers are an important part of the food chain because they provide energy and nutrients to the organisms that consume them, such as secondary consumers (carnivores) and tertiary consumers (top predators) .