Sexual organ strategy of ducks

2007/06/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia

Ducks have developed a long and spiral penis due to female fertilization competition. The females have the spiral vagina, but it is branched and rolled in the opposite direction to the penis of the males. For some ornithologists at Yale University, this vagina is a resource for the female to choose sperm. Many males can copulate with a female, but the female chooses which of them will allow her to reach the egg; the female uses the characteristics of the vagina to allow the female to enter only the chosen one. Bird species with stable partner throughout life have not developed a long or complex penis.