This medium-sized rattlesnake is only known to occur in its namesake, the Rupunini Savannah of Guyana in South America. This vast rolling plain is divided north to south by the Kanuku Mountains. Very little is known about the Rupunini rattlesnake likely due to its small and extremely rural locality. It probably feeds on small mammals and birds, and bites from this species can be lethal without treatment.

Fun fact: "Trigonicus" in the scientific name is in reference to V-shaped markings on its supraoculars, the scales directly above the eye!