More penis spines than you can shake a stick at.
ThinkStock / LisaStrachan / BuzzFeed
1. Male ducks have corkscrew-shaped penises.
2. Female ducks can keep the muscles in their vaginas taut so males' penises can't get in.
3. Female kangaroos have three vaginas.
4. Male rhesus macaque monkeys will "pay" to see female rhesus macaques' bottoms.
5. Nearly all bonobos are bisexual, and 75% of bonobo sex is not for reproduction.
6. Cat penises have spines or barbs made of keratin to scrape out competing sperm.
7. Some mammals, including some cats and dogs, have an actual bone in their penis.
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8. A male damselfly's tiny penis contains an even tinier spoon to scoop out leftover sperm from other males in the female's vagina.
9. In one species of elephant shrew, the end of the penis is spoon-shaped and contains a row of spines.
10. Elephant shrews are the only mammals, apart from primates and bats, that menstruate.
11. There's a tiny Australian mammal that has so much sex in a period of a few weeks that it basically disintegrates.
12. Female pandas only get excited ~sexually~ for a 24- to 72-hour window. It happens once a year at some point between February and May.
13. This is probably why artificial insemination is essential to the species' survival.
