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SEASONAL CHANGES IN THE MALLARD'S PENIS AND THEIR HORMONAL CONTROL
Author(s) -
HÖHN E. O.
Publication year - 1960
Publication title -
proceedings of the zoological society of london
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0370-2774
DOI - 10.1111/j.1469-7998.1960.tb05599.x
Subject(s) - penis , body weight , castration , seasonal breeder , testosterone (patch) , biology , hormone , zoology , medicine , anatomy , endocrinology
In adult wild mallards the penis weighs about 0·6 gms (0·05 per cent of body weight) for most of the year but increases to a weight of almost 3 gms. (0·3 per cent of body weight) at the height of the breeding season. In immature birds which had reached adult body weight the average penis weight was only 0·03 gms. (0·0026 per cent of body weight). The breeding season penile enlargement could be prevented by castration early in the spring. Evidence that Testosterone administration can cause enlargement of the penis in adult mallards was also obtained. Unilateral adrenalectomy did not effect penile or testicular weight.