Horse-fly is the most widely used English common name for members of the family Tabanidae. Apart from the common name “horse-flies”, Tabanidae are variously known as breeze flies, cleggs, klegs or clags, deer flies, gadflies or zimbs. Adult horse flies feed on nectar and sometimes pollen. Females of most species are require a blood meal before they are able to reproduce effectively, if at all. Much like male mosquitoes, male Tabanidae are not ectoparasitic and lack the mouth parts that the females use in drawing the blood on which they feed.
Most female horse flies feed on mammalian blood, but some species are known to feed on birds or reptiles and amphibians as well. Horse fly bites are more immediately painful than those of its mosquito counterparts, although it still aims to escape before its victim responds. The flies are very agile and adept at flying. Their bites may become itchy, sometimes causing a large swelling afterward if not treated quickly.