It's amazing, Look how a caterpillar is eating up close.

Caterpillars are the larval stage of members of the order Lepidoptera (an insect order consisting of butterflies and moths).

Caterpillars are usually voracious eaters. Many caterpillars are serious agricultural pests. In fact many species of moth are better known at the caterpillar stage because of the damage it does to fruit and other agricultural produce, whereas the moth is not a pest. On the other hand, various species of caterpillars are very beneficial to humans. For example, as a source of silk, food for humans and livestock, or for biological control of plant pests (weeds).

The video above shows how these animals eat their food voraciously, amazing isn't it.