The vertebrate extinction rate over the past century is approximately 22–100 times greater than background extinction rates, and large mammals are particularly at risk. Quaternary megafaunal extinctions have been attributed to climate change, overexploitation, or a combination of the two. Rhinoceroses (Family: Rhinocerotidae) have a rich fossil history replete with iconic examples of climate-induced extinctions, but current pressures threaten to eliminate this group entirely. The Sumatran rhinoceros (Dicerorhinus sumatrensis) is among the most imperiled mammals...