Woodcut taken from The History of Four-Footed Beasts and Serpents (1658) by Conrad Gessner. Depicts mammals and reptiles, both real and fantastical, in detailed woodcuts. The Boas was a creature described in Pliny the Elder's Historia Naturalis in 77AD. It was a snake that crept up on cows and attached itself to the udders. It would remain there sucking away all the cow's milk until the cattle was dry or dead. Early historians described dragons as huge serpents that killed their prey by coiling around them and "crushing them to death". A dragon is a legendary creature, typically with serpentine or reptilian traits, that features in the myths of many cultures.