The Zwaanendael Merman is an example of folk- or sailor's-art. Division of Historical and Cultural Affairs' museum curators believe that it was made in China in the mid-19th century, and is comprised of fish, hair, ivory, a shrunken monkey head, oak, stain, varnish, glass, and dye.

Creations such as the Zwaanendael Merman were conceived as pranks or side show curiosities at a time when sea captains were returning from the newly opened ports of East Asia with tall tales of exotic, never-before-seen creatures, and at a time when people were trying to learn more about the science behind human origins. Other names for creatures of this sort are "Fiji Merman," "Devil Fish," and "Jenny Hanivers."

The object that later became known as the Zwaanendael Merman belonged to the Martin family of Lewes for nearly a century after being presented to a family member by an old sea captain. Mrs. Martin's possessions were put up for auction after her death but a nephew set aside the Merman for display at the Zwaanendael Museum beginning in 1941. After the nephew's death, the Merman was almost sold off as part of an estate sale. Citizens of Lewes and members of the Lewes Historical Society responded to the threat by collecting donations which were used to purchase the Merman for $250. He was then presented as a gift to the Zwaanendael Museum by the Lewes Historical Society in 1985.