The island is home to an endemic cactus Echinocereus websterianus.
 Endemic fauna include the San Pedro Nolasco Island spinytail iguana (Ctenosaura nolascenensis) and, formerly, Pemberton's deer mouse (Peromyscus pembertoni ), a rodent which is now extinct.
 Large numbers of California sea lions frequent its surrounding waters and use the island as a haul-out.
The island is home to an endemic cactus Echinocereus websterianus.  Endemic fauna include the San Pedro Nolasco Island spinytail iguana (Ctenosaura nolascenensis) and, formerly, Pemberton's deer mouse (Peromyscus pembertoni ), a rodent which is now extinct.  Large numbers of California sea lions frequent its surrounding waters and use the island as a haul-out.
San Pedro Nolasco Island