Hydrus (the water snake) is a minor southern constellation. It was introduced by Johann Bayer in 1603. It should not be confused with Hydra.
... 23.8% from 45 to 64, and 7.9% who are 65 years of age or older. The median age is 35 years. For every 100 females there are 95.1 males. For every 100 females age 18 ...