Santa Catalina Island stands out among its sister islands because of its fauna and flora, found nowhere else in the world. Preferred by those who have a passion for nature and science. Although, many people also go there for an exceptional snorkeling and scuba diving experience.
The most famous of its endemic species is the “rattle-less” rattlesnake (Crotalus catalinensis). This snake species on Santa Catalina is believed to have lost its rattle through isolation and evolution. It has no defensive need for the rattle, as it has no predators on the island, and it can be stealthier and more successful in hunting its own prey without a rattle.
Ten species of reptiles inhabit Santa Catalina Island, all of them endemic, either at the level of species or subspecies.
The diverse vegetation of Santa Catalina includes a very particular population of an endemic giant cactus spices, know as the “Biznaga Gigante” — Giant Barrel cactus (Ferocactus diguetii), characterized by being the largest specimen in the entire Gulf of California, with heights of up to 12 feet and diameters of up to 4 feet, weighing several tons.
The french chemical engineer, Leon Diguet, became intrigued by the ethnology and natural history of Baja California Sur, while employed by the mining company “El Boleo” in Santa Rosalia between 1888 and 1894.
He made several natural history specimens collections, which got to the interest of the “Museum d´Histoire Naturelle” in Paris, that he was then commissioned to return as a field collector and investigator. Two conspicuous plants that bear his name are the giant barrel cactus of this Island (Ferocactus diguetii) and the bushy ocotillo (Fouquieria diguetii), found at the Baja California peninsula.
Santa Catalina is a granitic island (Johnson 1924). These granitic rocks might be related to those forming the southern tip of the Baja peninsula (Anderson 1950).