The navy rescued them three days later, uninjured. The three herpetologists arrived in a panga to study the island and its main inhabitants, rattlesnakes. The panga was supposed to return to pick them up but never did. Isla Tortuga (Tortuga Island) is an island in the Gulf of California, created relatively recently in geologic terms by the volcanism associated with the East Pacific Rise. It lies east-northeast of the city of Santa Rosalía, in the Mulegé Municipality. It has a surface area of 11.374 km2 (4.39 sq mi). The Tortuga Island rattlesnake (Crotalus tortugensis) is a species endemic to Isla Tortuga — it is found nowhere else. It is very abundant on the island and found everywhere on the island, except in the caldera of the volcano. The island has been visited by scientists from the U.S., Canada, France, Germany, China, Japan and Korea.