Deerflies are large, biting flies belonging to the family Tabanidae. They are commonly found in wooded areas and near water sources, especially during warm months. Adult deerflies are known for their distinctive yellow or brown bodies and large, bulging eyes. They are most active during the day and are attracted to movement and carbon dioxide emitted by animals and humans. These flies are notorious for their painful bites, which they use to feed on the blood of mammals, including deer and humans. Unlike some other flies, deerflies have a unique behavior of hovering around their hosts before landing. Their bites can cause irritation and allergic reactions in some individuals.