The European hornet is a conspicuous insect with a reddish-yellow head and thorax and a brown and yellow abdomen with black specks. Queens range from 25 to 35 millimetres in length, while adult hornet workers are somewhat smaller. Females and queens have an ovipositor modified into a sting, which is used to protect against enemies. The wings are small, thin and transparent.
Hornet nests are typically built in hollow trees, although they may also be found in barns, sheds, attics, birdhouses and abandoned beehives. The nests resemble those of wasps. European hornets are widespread throughout Europe, except the north and south.
Hornets have a one-year life cycle. Worker hornets and queens die off in mid to late autumn, and only fertilised queens survive over winter. The European hornet is less aggressive than its smaller relatives, such as wasps, and will sting only when the nest is disturbed or in self-defence. The sting of the European hornet is quite painful and can be life-threatening to those who are allergic to its venom. Multiple stings may also be fatal. Hornets generally feed on fruit sap.