The reproductive processes of certain mammals. III.—The reproductive cycle of the male ferret

Abstract

Observations have been made on the state of the testis, epididymis, vas deferens, and penis in 16 adult and 3 immature [male] ferrets, killed at different periods in the year. The testis and accessory sexual organs are in full activity from March to July. During Aug., Sept. and Oct. regression takes place. After a period of quiescence, preparation for the next breeding season begins in Dec. and results in gradual growth in testis, epididymis, vas deferens, and probably also in the penis. The weight of the testis and epididymis, calculated as a % of the body wt., is high during the breeding season and falls to the lowest point in Nov. The increase of weight in the epididymis is closely correlated with that of the testis. The diameters of the seminiferous and epididymal tubules show similar seasonal variation. Connected with the increase in the size of the epididymal tubules in the breeding season is an increase in the height of the epithelium and a reduction in thickness of the muscle layers. The vas deferens has a greater diameter in the breeding season than in the winter months, due largely to growth of the muscular coats. The interstitial cells of the testis undergo cyclic changes throughout the year. They are large and filled with fat in the breeding season, and small, with little fat, during anestrus.