This Bird's Body Is Half Male, Half Female. So Is Its Brain.

Photo Credit: Shirley Caldwell, photo taken in Erie, Pennsylvania

This type of a split sexuality is termed gynandromorph. According to the article, this  anomaly has been observed in birds, crustaceans and butterflies. Female birds have both sex chromosomes (W and Z in birds) and males only carry one (Z). If a female egg has two nuclei, one could contain the W chromosome and the other the Z chromosome. If fertilized, the egg could develop with ZZ and ZW chromosomes resulting the development of a half-male and half-female bird.


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