Sexual selection. Are ducks impressed by drakes' display?

Research paper by K G KG McCracken, R E RE Wilson, P J PJ McCracken, K P KP Johnson

Indexed on: 15 Sep '01Published on: 15 Sep '01Published in: Nature


Surprisingly few birds have penises, but among those that do, the Argentine lake duck (Oxyura vittata) tops the bill - the penis of this small stifftail duck from South America is shaped like a corkscrew and, at almost half a metre long, is the largest of any bird measured so far. Factors responsible for the evolution of this remarkable organ could include runaway selection, whereby drakes with longer penises gain dominance and copulate with more females, or preference by females for drakes with longer and more decorated penises.