The basic dentition of the black rhino is four premolars and three molars in both upper and lower jaw. (Gray 1861 and Roberts 1951). Ritchie (1963) in Kenya, has recorded three premolars and three molars as a variation to the standard dentition; he mentions that the first premolar is missing in older animals, especially in the lower-jaw. This condition has also been found in Hluhluwe, in fact almost 40 per cent of the sample lack the first premolar in the lower jaw. Of the fifty-one skulls of sub-adult and adult animals examined, the variations found within the cheek teeth are as follows: Number of Maxilla Mandible Specimens 4 Premolars, 3 Molars 4 Premolars, 3 Molars 27 4 Premolars, 3 Molars 3 Premolars, 3 Molars 19 3 Premolars, 3 Molars left 3 Premolars, 3 Molars 1 4 Premolars, 3 Molars right 4 Premolars, 3 Molars left 3 Premolars, 3 Molars 1 3 Premolars, 3 Molars right 3 Premolars, 3 Molars 3 Premolars, 3 Molars 2 3 Premolars, 3 Molars 4 Premolars, 3 Molars 1 It can thus be seen that there is considerable variation from the standard formula within this sample. Within the collection, three of the specimens have two pairs of lower incisors, two animals being calves (H 40 and H 888), the other a fourteen-month-old male (H 11). A further two skulls have one pair of incisors in the lower jaw, on a mature animal (H 29) and the other from a well developed foetus (H 101). These incisors are not the chisel-like incisors found in the Asian rhino, but are simple cylindrical teeth with a closed root. The largest incisors were from the mature animal (H 29), and measured 22.7 mm. in length and 4.9 mm. in diameter. Flower (1876) recorded rudimentary incisors in both jaws of a young black rhino from Abyssinia. He mentions that these incisors, if ever present, disappear soon after birth. Because of their size, it is highly unlikely that these incisors protrude through the gums, and certainly do not assist in browsing. Perhaps those present in calves could be of some use in suckling.
Diceros bicornis - South Africa. Within the collection, three of the specimens have two pairs of lower incisors, two animals being calves (H 40 and H 888), the other a fourteen-month-old male (H 11). A further two skulls have one pair of incisors in the lower jaw, on a mature animal (H 29) and the other from a well developed foetus (H 101). These incisors are not the chisel-like incisors found in the Asian rhino, but are simple cylindrical teeth with a closed root. The largest incisors were from the mature animal (H 29), and measured 22.7 mm. in length and 4.9 mm. in diameter. Flower (1876) recorded rudimentary incisors in both jaws of a young black rhino from Abyssinia. He mentions that these incisors, if ever present, disappear soon after birth. Because of their size, it is highly unlikely that these incisors protrude through the gums, and certainly do not assist in browsing. Perhaps those present in calves could be of some use in suckling.
