A hornet is a type of wasp, but the distinction between them involves specific differences in taxonomy, physical traits, and behavior. Wasps are a broad group of predatory or parasitic insects belonging to the order Hymenoptera. Hornets represent a small, specialized subset within this larger classification, making the relationship one of category and subcategory. Understanding the specific features of true hornets provides clear differentiating factors for identification.
The Taxonomic Relationship
All true hornets belong exclusively to the genus Vespa. This genus is housed within the subfamily Vespinae, which is part of the family Vespidae, commonly known as the vespid wasps. Every insect classified as a hornet is fundamentally a type of wasp and a member of the Vespidae family, which also includes yellow jackets (Vespula and Dolichovespula) and paper wasps (Polistes).
Yellow jackets and paper wasps are also Vespids, sharing the same family as hornets, but they do not belong to the genus Vespa. This means that while they are all social, stinging insects with similar life cycles, true hornets are a distinct lineage within the larger wasp family tree. The bald-faced hornet is a common point of confusion, as its common name includes “hornet,” but it is scientifically classified as a species of yellow jacket (Dolichovespula maculata).
Key Physical Distinctions
Physical size is one of the most immediate differentiators, as hornets are typically the largest of the eusocial wasps, with some species reaching lengths of over one inch. Yellow jackets are often smaller and more compact, usually measuring about half an inch long. Hornets also possess a broader head and a more rounded abdomen compared to the sharper, more defined “waist” and tapered abdomen seen in many common wasps.
The coloration of true hornets tends to be less vibrant than the stark black and bright yellow of a typical yellow jacket. Species like the European hornet often display more subdued markings, featuring brown and deep reddish-brown tones mixed with yellow or orange stripes. This differs from the high-contrast patterns and distinctive anchor-shaped black marks often found on the first abdominal segment of yellow jackets. Hornets can also be distinguished from other vespine wasps by the relatively large area on the top margin of their head, known as the vertex.
Colony Structure and Behavior
Hornets and other vespid wasps exhibit differences in where and how they construct their nests. True hornets typically build large, fully enclosed nests made of a papery pulp, which often take on a football or teardrop shape and are frequently found suspended high up in trees or within hollow cavities. This contrasts with the open, umbrella-like nests of paper wasps, where the hexagonal cells are visible from the underside, or the subterranean nests often favored by yellow jackets.
The primary diet also sets them apart, as hornets are dedicated predators that primarily hunt other insects, including other wasps, to feed their developing larvae. While yellow jackets also hunt, they are more famously known for becoming aggressive scavengers later in the season, often attracted to human food, sugary drinks, and carrion. In terms of aggression, both will defend their nests vigorously, but hornets are highly territorial and their defense is focused on protecting the structure. Yellow jackets, especially when scavenging, are often regarded as having a more persistently aggressive temperament when they encounter food sources near humans.