MALE REPRODUCTIVE ORGANS OF THE AFRICAN ELEPHANT, LOXODONTA AFRICANA

Abstract

Results are presented of detailed dissections of the reproductive tracts of eight adult male African elephants and of one full-term male foetus, together with additional information obtained from the examination of a number of other bulls and cows. A notable feature of the elephant''s tract is the absence of a pampiniform plexus, cremaster muscle and inguinal canal; this is consistent with the intra-abdominal location of the testes. The weight of the testes and the mean diameter of the seminiferous tubules appear to be related to the size and hence the age of the animal. Active spermatogenesis was observed in all the adult testes examined. Testosterone was isolated from the testes and identified by infra-red spectroscopy; the testicular testosterone concentrations ranged from 3 to 490 [mu]g/100 g testis and were apparently unrelated to season, age, behavioural status or vesicular fructose concentrations. The elephant has no anatomically distinct epididymis. The wolffian duct is highly convoluted and probably several hundred metres in length. Its caudal half has an unusual histological appearance, with a very folded and extremely vascular lamina propria. The ampullae are large glandular structures, opening into the ducts of the corresponding seminal vesicles. The seminal vesicles are large, thick-walled sacs that contain up to 350 ml of a watery secretion rich in fructose. The prostate varies in shape considerably between animals, being uni-or multilobular. The bulbo-urethral glands are large, and full of a highly viscous secretion. The penis has a well-developed corpus cavernosum penis and large paired levator penis muscles on its dorsal surface. The temporal gland is apocrine in nature, with a strongly smelling serous secretion. Its secretory activity appears to be unrelated to the reproductive status of the animal or the body temperature. The mean deep body temperature was found to be 36.8[degree] C (range 36.2 to 37.5[degree] C). Spermatozoa, recovered within 2 to 6 hours of death from the caudal end of the wolffian duct and the ampullae, were immotile, but could be partially activated by dilution with vesicular secretion. At least two of the elephants had had a retrograde ejaculation when they were shot, and in one instance motile spermatozoa were recovered from the bladder 6 hr. after death.