How is an animal's life cycle different from the life cycle of an insect that goes through complete metamorphosis? The infant animal looks similar to the adult animal, but the insect larva looks different from the adult insect. Animals start their life cycles as an egg, but insects start their life cycles as a pupa. The animal develops in a chrysalis or a cocoon, but the insect grows with small gradual changes. The eggs of an animal are laid by the mother, while the embryo of an insect develops inside its mother.