Reproductive behaviour in ungulates

There are exceptional reports of durable pairings in rhinoceros. Bourliere (Mammals of the world) gave description of such pairing in Rhinoceros unicornis. In the breeding season they pair amd Bourliere describes a case in which one pair was seen to remain exclusively together for 4 months.

Diceros bicornis is reported by Young as having a delayed and singularly unique manner of penile protrusion and erection. On initial protrusion the penis is bent downwards and backwards and only later does it become straightened and directed forwards.