High Quality Content by WIKIPEDIA articles! To be as "mad as a March hare" is an English idiomatic phrase derived from the observed antics, said to occur (incorrectly) only in the March breeding season of the Hare, genus Lepus. The phrase is an allusion that can be used to refer to any other animal or human who behaves in the excitable and unpredictable manner of a "March hare". 'As Mad as a March Hare' first appeared in Chaucer's "Friar's Tale" in the late 14th century. A later recorded use of the phrase occurs in the writings of Sir Thomas More.