The normal body temperature of a Black rhino ranges from 34.5 oC to 37.5 oC. The pulse is 30 to 40 beats per minute, and respirations are six to twelve breaths per minute (Fowler and Miller, 2003).
A rhino horn is comprised of thousands of compressed hair-like strands. The main component of the horn is keratin, making it extremely hard and tough, but it can be broken or split during fighting (Adcock and Amin, 2006).
The anatomy and digestive system in rhino species roughly resembles that of horses. Rhinos are monogastric animals with a hindgut-fermentation chamber. Microbial fermentation of plant fibre in the hindgut (cecum and large intestine) provides the main energy source for rhinos.
Reproductive Physiology – Female
Female rhinos that have not bred have a hymen, the membrane that covers the vaginal opening which is often present cranial to the urethral opening. In several cases, a persistent hymen has been associated with a failure to breed, evidenced by the male’s failure to achieve intromission after mounting. Rhinoceros have a long vagina characterised by longitudinal folds. These folds can make the opening of the cervix difficult to locate. The cervical canal is long and characterised by interdigitated folds. The uterus is bicornate, forming two horns after a short uterine body. The uterus of a pregnant rhino is characterised by diffuse placentation, meaning that almost the entire surface of the ventral outgrowth of the hindgut of the early embryo and the outermost membrane of the sac enclosing the foetus are used to form the placenta. The paired mammary glands are inguinal in position.
Reproductive Physiology – Male
In the male Black rhino, the testicles are held close to the body along the preputial fold and are positioned horizontally as in the horse. The male reproductive tract includes vesicular glands, bulbourethral glands, and prostate. The relaxed penis is curved caudally, a position that results in the characteristic backward directed urination in male rhinos. The penis has notable horizontal flaps. Natural intromission may last up to 45 minutes.