Animals food chains are connections between animals who prey on each other. For example bear -> fish -> smaller fish -> plant. Food webs are a more sophisticated version of food chains.
Animal food chains are ways of looking at predator and prey. The chain usually starts with a plant, then go to a herbivore, which is then followed by various ominvores or carnivores at the top.
Food chains in the animal ecosystem start out with the primary producer. They then move on to the primary consumer, secondary consumer, tertiary consumer, and lastly the quaternary consumer.