A maggot is the larva of a fly, which is the earliest phase of a flys life cycle. Maggots are legless creatures that are usually white, but some species have a red or brown hue. They are typically found in decaying organic matter, such as garbage, compost, or animal feces. Maggots have light-sensitive cells that cover their body, which act as eyes to sense the world around them. They feed on dead or living vertebrate tissues for a variable period and are important in recycling carrion and garbage, attacking crops and foodstuffs, spreading microbial infections, and causing myiasis. Maggots are also used in forensic entomology to determine the time of death, as well as in fishing, wound debridement, and composting. Some species of maggots can change their feeding habits depending on their stage of development, often transitioning from plant matter to animal matter. Maggots pose a number of health risks to humans, including myiasis, which is the infection of human tissue with maggots. However, certain species of maggots, raised in sterile laboratory conditions, are sometimes deliberately introduced onto patients wounds for a practice called maggot debridement therapy.