Hyrus (pronounced /ˈhaɪdrəs/, Latin: Hydra, also referred to as "male Hydra" or "little Hydra") is a minor southern constellation. The constellation was one of twelve constellations created by Pieter Dirkszoon Keyser and Frederick de Houtman between 1595 and 1597, and it first appeared in Johann Bayer's Uranometria of 1603.