Dillos After Dark: A look into the strange reproductive ecology of nine-banded armadillos. First off — one of peoples’ favorite fact about armadillos is the relative size of their penises. And this is true — armadillos have the longest penises of any mammal relative to their body length. The giant armadillo’s penis is about 60% of their body length (~15”) and the nine-banded is about 30% of their body length (~8-10”). Armadillos are typically solitary, so if you see more than one, they are eithe