Chet Van Duzer's "Sea Monsters on Medieval and Renaissance Maps" (British Library, 2013) charts the evolution of the mythical creatures that adorned atlases from the 10th century through the 17th century.
Cartographers used the beastly art to illustrate mysterious, unexplored regions of the globe and the possible dangers of seafaring.
Despite their wild appearance, many of these creatures were based on real animals.
"The creatures look purely fantastic. They all look like they were just made up," Van Duzer, a map historian at the Library of Congress, said here Thursday (Sept. 5) in a talk about his book. "But, in fact, a lot of them come from what were considered, at the time, scientific sources."
