The northern white rhinoceros (Ceratotherium simum cottoni), or northern square-lipped rhinoceros, is one of two subspecies of the white rhinoceros (the other being the southern white rhinoceros). Formerly found in several countries in East and Central Africa south of the Sahara, this subspecies is a grazer in grasslands and savanna woodlands. Since 19 March 2018, there are only two known rhinos of this subspecies left, called Najin and Fatu, both of which are female; barring the existence of unknown or misclassified male northern white rhinos elsewhere in Africa, this makes the subspecies functionally extinct. The two female rhinos belong to the Dvůr Králové Zoo in the Czech Republic but live in the Ol Pejeta Conservancy in Kenya and are protected round-the-clock by armed guards.