Duck penises grow bigger when there are more males around
Dan Baldassarre on Twitter: "Just a quick reminder that the Lake Duck exists. This unassuming fella has a twisted secret... No, literally. It has a 42.5 cm penis twisted up inside its
6 Animals With the Biggest Penises - YouTube
Lake duck - Wikipedia
Lake duck - Wikiwand
Duck Penises Grow Bigger Among Rivals
Male ducks worry about penis size too according to study | Boing Boing
Duck Penis Length Depends on Other Guys | WIRED
Why do male Mallard ducks have glossy green heads? - Quora