 The subspecies C. n. nigra became extinct by human exploitation in the 19th century . Another subspecies , C. n. abingdonii , became extinct on 24 June 2012 with the death in captivity of the last remaining specimen , a male named Lonesome George , the world 's " rarest living creature " . All the other surviving subspecies are listed by the IUCN as at least " Vulnerable " in conservation status , if not worse . 
