Flies eat animal feces and decaying matter, including rotten fruits, vegetables and meats. Flies can only ingest food when it is in a liquid form.
When a fly finds food that's solid, it rubs the food with bristles on its proboscis, a tubular appendage from its mouth. Then, the fly vomits a mixture of saliva and digestive juices onto the food. This breaks down the food and turns it into a liquid form. Flies are unable to chew or bite. They absorb liquid like a sponge, and it goes straight into their stomachs. Flies look for food by tasting things with their feet and palps.