Hydra Island is a second, smaller island sitting offshore from the main island. The island takes its name from the DHARMA Initiative's Hydra station which is located there, as stated by Dr. Chang. It is described by Ben as being about the twice the size of Alcatraz Island, which makes the land area about 0.06 square miles (just under 1/4 mile by 1/4 mile). The DHARMA Initiative used the second Island as the location for the Hydra, a Zoological Research Station. Their facility included an aquarium with an underwater section where Jack was held prisoner. Additionally there were outdoor cages with facilities for Skinnerian-style conditioning.rather where they worked on what they refer to as "projects". Most Others prefered to remain at "home"on the main island.