MALE PSEUDOHERMAPHRODITISM IN THE BOWHEAD WHALE, BALAENA-MYSTICETUS

Examination of two bowhead whales, Balaena mysticetus, revealed an unu sual assembly of reproductive structures. Although the external phenot ype was female, the gonads were underdeveloped testes. In the more tho roughly studied of the two whales, all derivatives of the mesonephric (wolffian) and paramesonephric (mullerian) ducts were absent, and ther e was an apparently normal male karyotype (40 autosomes + XY). These f indings suggest a failure of androgen expression consistent with the s yndrome of complete testicular feminization reported in other species. Structural comparisons with two normal male bowheads confirm abnormal development in the two affected whales.