| In 2005, a psychologist and an economist taught a group of monkeys the concept on money - Soon, the monkeys began to engage in prostitution. |
| Penguins have been known to engage in "prostitution." They will have sex with males in exchange for food and pebbles. |
| Male ducks literally shed and regrow their penises. |
| Earthworms are hermaphrodites. They have both male and female parts. But they cannot impregnate itself. |
| The female Orb-web spider eats the male during sex, but the male's penis is detachable and still finishes the job. |
| Female porcupines have been witnessed using wooden sticks as "dildos." |
| The male spiny anteater has a 4-headed penis. |
| Only female humans and horses have hymens. |
| Honey bees testicles explode during sex and then they die! |
| Hippos attract mates by urinating and defecating. |