Aruba Island Rattlesnake (Crotalus unicolor)ReptilesThe Aruba Island rattlesnake is one of the rarest rattlesnakes in the world. The Zoo participates in a Species Survival Plan, a collaborative effort of institutions accredited by the Association of Zoos & Aquariums, to maintain Aruba Island rattlesnakes in human care as well as support the study and conservation of the species in the wild. Risk Status Species at Risk (IUCN—Critically Endangered)