The entire life cycle of flies plays an important role in the decomposition of a dead body. First, a fly lays up to 300 eggs on the outside of the body, which hatch within a day. The fly larvae -- maggots -- are very efficient at consuming flesh and start by scooping up fluids being expelled from the corpse. Within a day, the maggots enter their second larval stage and burrow into the body. They operate as a social unit and feed on decaying flesh, and they also spread enzymes that break the body down into gelatinous goo. Because of the structure of maggots' mouths, they can actually breathe and eat at the same time. They do so nonstop until they leave the body about seven days later as prepupae. At that point, they will have consumed up to 60 percent of a dead human body.