biological characteristics of late maturation, slow growth, few offspring and long periods of time between each breeding period, contributes to the vulnerability of the species. Conservation efforts for the habitats of Santa Catalina Island as well as the prey of C. catalinensis would improve the rattlesnake's risk of extinction. Habitat The habitat on Santa Catalina Island consists of Gulf Coast desert plants. This snake is often found on the western side of the island within the many arroyos. The Santa Catalina rattlesnake is also found in plains, bottoms of ravines, and riverbeds of streams. They are found on summits of rocky hills where they often find shelter in the rock crevices. One of the main shelter options is dense vegetation which can also be used as an efficient way to find prey. It is believed that the snakes find shelter in the vegetation to help maintain a constant body temperature as well as use the density to hide from predators. Behavior While most members of this genus, Crotalus, are almost entirely terrestrial due to their heavy body structure, this species' small size makes it a swift and skillful climber. Previous researchers hypothesized that the ability of the Santa Catalina rattlesnake to climb, combined with its lack of a rattle allowed it to hunt roosting birds, but detailed research into the species’ diet has revealed that the Santa Catalina rattlesnake maintains a mammal-based diet like most rattlesnakes. Further inquiry into the arboreal behavior of this island species has shown individuals actually spend the majority of their time on the ground. Individuals were most likely to be found in low branches of bushes during July, the hottest month on the island. The Santa Catalina rattlesnake is thought to climb off of the hot ground and into bushes to thermoregulate. The snake expresses thermo-conformist behavior which means that its body temperature correlates with soil temperature. This is a common trait among other rattlesnakes. Unlike most species of rattlesnakes, the Santa Catalina rattlesnake is often observed exposed; it does not tend to hide. Currently, the greater evidence supports the theory that the Santa Catalina rattlesnake has evolved away from having a rattle because it has no need for a warning mechanism against predators. Though it was previously thought that the snakes presented diurnal and nocturnal habits, more evidence suggests that they are completely nocturnal, even during winter months. The Santa Catalina Rattlesnake does not