between black and white rhinos is the shape of their mouths – white rhinos have broad flat lips for grazing, whereas black rhinos have long pointed lips for eating foliage. There are two living Rhinocerotini species, the Indian rhinoceros and the Javan rhinoceros, which diverged from one another about 10 million years ago. The Sumatran rhinoceros is the only surviving representative of the Dicerorhinini. A subspecific hybrid white rhino (Ceratotherium s. simum × C. s. cottoni) was bred at the Dvůr Králové Zoo (Zoological Garden Dvur Kralove nad Labem) in the Czech Republic in 1977. Interspecific hybridisation of black and white rhinoceros has also been confirmed. While the black rhinoceros has 84 chromosomes (diploid number, 2N, per cell), all other rhinoceros species have 82 chromosomes. Chromosomal polymorphism might lead to varying chromosome counts. For instance, in a study there were three northern white rhinoceroses with 81 chromosomes. Species White There are two subspecies of white rhinoceros: the southern white rhinoceros (Ceratotherium simum simum) and the northern white rhinoceros (Ceratotherium simum cottoni). As of 2013, the southern subspecies has a wild population of 20,405—making them the most abundant rhino subspecies in the world. The northern subspecies is critically endangered, with all that is known to remain being two captive females. There is no conclusive explanation of the name "white rhinoceros". A popular idea that "white" is a distortion of either the Afrikaans word wyd or the Dutch word wijd (or its other possible spellings whyde, weit, etc.,), meaning "wide" and referring to the rhino's square lips, is not supported by linguistic studies. The white rhino has an immense body and large head, a short neck and broad chest. Females weigh and males . The head-and-body length is and the shoulder height is . On its snout it has two horns. The front horn is larger than the other horn and averages in length and can reach . The white rhinoceros also has a prominent muscular hump that supports its relatively large head. The colour of this animal can range from yellowish brown to slate grey. Most of its body hair is found on the ear fringes and tail bristles, with the rest distributed rather sparsely over the rest of the body. White rhinos have the distinctive flat broad mouth that is used for grazing. Black The name "black rhinoceros" (Diceros bicornis) was chosen to distinguish this species from the white rhinoceros