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!
