Yale researchers have found that some female duck genitalia is evolving, forming clockwise spirals, to avoid impregnation from undesirable yet aggressive males. The study builds upon a finding by Yale in 2007 that first noted how

duck’s sexual organs had been morphing. While most birds are phallus-free, ducks a… Read the full story on TreeHugger

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Female Ducks Evolving to Avoid Endowed Males