Scientists hope to measure the force experienced by female ducks when a drake’s penis penetrates them (can I call it ‘penile force’?). Meanwhile, the battle of the sexes rages on…

Update April 2, 2013: The original video I had on here, which explained the purpose of the research, is no longer available. But here’s a cool video from Patricia Brennan’s lab showing a duck penis as it goes through various female genital-shaped barriers. You can read about Dr. Brennan’s research here.