Swallowtail butterflies are a group of butterflies in the butterfly family Papilionidae (papilio means butterfly & moth in Latin). There are an estimated 550 known species and hundreds more waiting to be discovered. The common name, Swallowtail, comes from the fact that a majority of the members of this group of butterflies have an extension at the end of each hindwing that resembles the tails of swallows. You can witness these extensions in the picture of Papilio Ulysses. However, if you look at the small variety of Swallowtails listed in my shop you may notice that some members do not have this extended tail. Therefore, this feature is not the only characteristic used in the classification of swallowtails.
The interesting fact about these “tails” is their evolutionary feature. Birds love to eat butterflies and when they attack butterflies they go for the neck or body, which would be a clear-cut kill instead of a piece of wing. In response to this, swallowtails have evolved tail extensions that resemble their necks and body. Therefore, a bird will see these extensions as a “body or neck” and be directed away from the butterfly’s vital organs and fly away with a piece of wing, leaving the butterfly with its life.