At the third level carnivores eat the herbivores (the secondary consumer level), and at the fourth level secondary carnivores eat the primary carnivores (the tertiary consumer level).

• 肉食动物构成了第三营养水平，它们以草食动物为营养来源，是次级消费者，而位于第四营养水平的肉食动物会吃上一级肉食动物，为三级消费者。