Many species in the stiff-tail duck family have relatively long penises, said McCracken, but more along the lines of 8 inches (20 centimeters). The base of the Argentine lake duck's penis is covered with coarse spines, while the tip is soft and brush-like. The researchers think a drake may use the brush-like tip as a sort of cleansing instrument before ejaculation to remove sperm in the females oviduct that was deposited by another suitor, thus increasing the mating drake's chances of paternity.
Similar sperm-removal behavior has also been seen in some fish and insect species. The unusually long penis is probably part of a reproductive strategy designed to increase the male Argentine duck's success in a highly competitive environment. Stiff-tail ducks are promiscuous, said McCracken, and Argentine lake ducks are particularly so. Although information on their mating habits is limited, researchers know that the courtship displays to attract femalesand fend off other malesare elaborate, vigorous, and typically performed in the presence of other ducks. (!!!!!!!!!!!!!!!Voyeur Ducks! Quack for me, Baby!!!) There is very little pair-bonding between males and females, and the female ducks are often resistant to mating.
"Our best guess is that the birds use [the long penis] as a kind of lasso," McCracken said. "The males have to chase the females, and even during copulation the females are trying to escape." McCracken and his colleagues don't discount the idea that sexual selectionfemale preference for a longer penishas played a role in the development of the Argentine duck's very long penis. They think it is more likely, however, the result of limited access to females, intense sperm competition, and the need for male dominance over females.
Similar sperm-removal behavior has also been seen in some fish and insect species. The unusually long penis is probably part of a reproductive strategy designed to increase the male Argentine duck's success in a highly competitive environment. Stiff-tail ducks are promiscuous, said McCracken, and Argentine lake ducks are particularly so. Although information on their mating habits is limited, researchers know that the courtship displays to attract femalesand fend off other malesare elaborate, vigorous, and typically performed in the presence of other ducks. (!!!!!!!!!!!!!!!Voyeur Ducks! Quack for me, Baby!!!) There is very little pair-bonding between males and females, and the female ducks are often resistant to mating.
"Our best guess is that the birds use [the long penis] as a kind of lasso," McCracken said. "The males have to chase the females, and even during copulation the females are trying to escape." McCracken and his colleagues don't discount the idea that sexual selectionfemale preference for a longer penishas played a role in the development of the Argentine duck's very long penis. They think it is more likely, however, the result of limited access to females, intense sperm competition, and the need for male dominance over females.
