The long-tailed rattlesnake (Crotalus stejnegeri) is listed as "vulnerable." This species lives in western Mexico. It is a rare species, according to the IUCN, and is known only from a few specimens. The population is likely decreasing due to loss of habitat caused by logging and agriculture.
The Santa Catalina Island rattlesnake (Crotalus catalinensis) is "critically endangered" because of its limited range (it is found only on Santa Catalina Island off the coast of California), over-collection and killing by humans and feral cats.
The Tancitaran dusky rattlesnake (Crotalus pusillus) is listed as "endangered" because it is found only in a small area of Mexico; however, no population information is available.
Most species of rattlesnakes are not endangered, according to the International Union for the Conservation of Nature (IUCN). However, the group's Red List of Threatened Species lists three species of concern: