This large rattlesnake can be found in the southwestern corner of California and south into Baja California including several islands. Its distinctive and bright red coloration develops as it ages from juvenile into adulthood. It inhabits elevations below 5000ft and prefers rocky outcrops, arroyos, hillsides, and coastal scrub habitats.

Red Diamond rattlesnakes are specialist predators, which feed mostly on small mammals. This species feeds year-round as the opportunities present themselves. There is no ontogenetic shift, unlike many other species, and juveniles are equally as likely to be found eating rodents as adults.

They can reach sizes of up to 162cm (64in), possibly larger. Males are on average larger than females.

Fun fact: The scientific epithet "ruber" means "red" in Latin. This species was named for its striking reddish coloration.