War Between the Sexes: The Co-evolution of Genitalia in Waterfowl.

0 Comments | M2 Presswire, May, 2007

M2 PRESSWIRE-1 May 2007-YALE UNIVERSITY: War Between the Sexes: The Co-evolution of Genitalia in Waterfowl(C)1994-2007 M2 COMMUNICATIONS LTD RDATE:30042007 New Haven, Conn. -- A team of biologists at Yale University and the University of Sheffield discovered anatomical details about the female reproductive tract in waterfowl that indicate that male and female anatomy have co-evolved in a "sexual arms race." In most birds, copulation consists of a simple, and rather chaste, "cloacal kiss." But, avian diversity includes a few ancient lineages that retained the grooved phallus found in their reptilian ancestors.

Among living birds, the waterfowl are one of the lineages that still have the phallus. Waterfowl are also distinct in having great diversity among...