There’s an Argentine lake duck that has a corkscrew-shaped penis as long as its body, almost half a meter:Argentine Duck
Surely he doesn’t insert the entire length into his mate, so nobody knows exactly why he possesses such an oversized appendage.
Contemplating this duck’s love life brings to mind Larry Niven’s classic essay about Superman’s hypothetical sexual difficulties:Man of Steel, Woman of Kleenex
I found out about the Argentine duck in THE DAWN OF THE DEED: THE PREHISTORIC ORIGINS OF SEX, by paleontologist John A. Long. Although this author focuses mainly on the prehistoric origins of internal fertilization with extended discussion of extinct fish and modern sharks, the book also devotes space to some other strange sexual practices in the animal kingdom. Life right here on Earth offers plenty of ideas for weird alien biology.
Margaret L. CarterCarter's Crypt