| Male koalas bears have a penis with two heads. |
| "Child abuse" has been witnessed in birds. Abused chicks will more likely grow up to abuse other younger birds. |
| To avoid being eaten by the female, the male spider will often tie her up before mating. |
| Vaginas stay lubricated with a substance called "squalene," this same substance is also found in the livers of sharks. |
| When a male honey bee climaxes during sex, his testicles explode and he dies. |
| All male mammals have a sudden increase in stamina and sexual performance when a new female is introduced during or right after sex. |
| The mallard duck is the only animal who reproduces exclusively by gang rape, and have been known to partake in homosexual necrophilia. |
| Flatworms engage in "penis fencing" as a mating ritual, each worm trying to stab the other. |
| Some male spiders voluntarily `castrate` themselves during sex in order to increase their chances of fathering offspring. |
| Self-castrate then run away. The eye-watering way a male spider avoids being eaten by its mate after sex! |