The seminiferous cycle of the rhinoceros

The seminiferous cycle of the rhinoceros was investigated for the first time using testicular tissue from captive white (Ceratotherium simum, n = 2) and black (Diceros bicornis, n = 1) rhinoceroses. Stages of the seminiferous epithelial cycle were characterised using the tubular morphology method and relative frequencies of each stage determined. This method allowed for the identification of eight stages of cellular associations characteristic of the seminiferous cycle in white and black rhinoceroses. The eight stages of the seminiferous cycle observed closely approximated the stages previously described for the domestic horse (Equus caballus). Premeiotic (stages I-III), meiotic (stage IV) and postmeiotic (stages V-VIII) represented 44.8%, 5.3% and 49.9% of the seminiferous cycle respectively.