Sheeeeeit... @Jontro still wishes he was a duck Patricia Brennan strolls through an outdoor aviary with a net in hand. She scoops up a duck, turns it onto its back, and applies pressure to its belly. "If you know exactly where to press, you can pop the penis out," she explains. "They're quite cooperative. The males get used to being handled." The biologist didn't plan to spend more than a decade coaxing ducks to reveal their genitals to her... Owing to an odd quirk in their physiology, ducks develop their penises anew each year. When the changing amount of daylight signals the start of breeding season, their genitals begin to grow. At the end of the breeding season, they shrink. .... https://www.nationalgeographic.com/animals/article/duck-penis-size-social-group-study