Flies are omnivorous animals and will eat almost anything from nectar of plants, to sap and even animal blood. The fly is able to prey on such things at it uncoils it's long, straw-like tongue which then sucks the liquid into the fly's body. The maggots which are the baby flies, are known to feet primarily on decomposing matter such as excrement and flesh.
Due to it's small size and abundance, the fly is preyed upon by a wide variety of predators around the world including amphibians such as frogs, toads and newts, fish that eat flies that land on the surface of the water, reptiles such as lizards and small mammals.
Flies have an extremely short lifespan, only living for about a month. The female fly lays her eggs in decomposing material, both plants and animals, which hatch very quickly. The eggs hatch into fly larvae which are more commonly known as maggots and quickly transform into an adult fly. It is thought that the process from egg to fly takes just under 2 weeks.