Blonde Pigtailed Girl Strips On The Tree Trunks

Alternately, the plural term pigtails may be applied to a pair of two braids or ponytails on opposite sides of the head. In British English the term "pigtail" or "pigtails" refers specifically to bunched hair that has been plaited. Unplaited pairs are "bunches" and a single bunch, regardless of position on the head, is a "ponytail".
Word origin and usage
The term pigtail appears in English in the American colonies in the 17th century to describe a twist of chewing tobacco. One of the steps in processing the tobacco was to twist a handful of leaves together to form a compact bunch that would then be cured (dried, either with or without smoking). The term "pigtail" was applied to the bunch based on its resemblance to a twisted pig's tail.