The cute face and innocent eyes of a koala hide a mischievous sprite, with one of the most interesting sex lives in the animal kingdom, worthy of a national Wild Koala Day in their honour! Here are five amazing facts, sure to raise some eyebrows!

Female Koalas have 3 vaginas

The animal world has many shocking secrets, and not all bodies are made the same. Under all that fluff and chubby cuteness, there’s a lot of woman!

How: She still has a single opening to the exterior, but just inside the vagina branches into three.

Why: Its part of her marsupial heritage. The plumbing runs through the middle of the baby factory, preventing the three branches from fusing into one.

Male koalas have a forked penis

Watching a male Koala become aroused is like a scene from an alien horror movie. Not only does his penis have two heads, it is pink, very large and prominently-veined. The greater shock is that most marsupials have forked penises. Possums, wombats, sugar gliders, bilbies. But most have slender, elegant appendages. Koalas are unusual is that they are well-endowed in both girth and length.

How: the two heads don’t stick out far and can be retracted.

Why: No-one really knows. Maybe it helps sperm enter two of the three branches of the vagina?

Koala sex is voice-activated

It's not a guy’s looks, wealth or power that turns on a lady koala, its his voice. The deepest bass and baritone notes are a Koala lady’s aphrodisiac. Barry White, Louis Armstrong and Leonard Cohen would have done well as Koalas. Male Koalas broadcast their availability in breeding season – October to March. Their voice travels far, and clucky females make their travel plans to the deepest voice in the land.

How: low sounds are usually produced by large bodies, so a deep voice is an indicator of a large, strong male that will father strong offspring.

Why: Low notes travel further, so these males have a wider audience.

Koalas ovulate only after they have sex

Koalas don’t waste anything, not even eggs! They are ‘induced ovulators’. Here’s another of those shocking animal secrets: animals don’t do things like we do. Induced ovulation – egg release after sex – is not uncommon. Cats, rabbits and camels do it too. Koala girls don’t have a period or monthly oestrus cycle. They do it all in a rush, once a year, when sex is had and pregnancy is likely. Imagine all that tension bottled up into one insane week per year.

How: Hormones released in response to sex cause the ovary to release an egg, which is fertilised by stored sperm.

Why: It is suggested that it is good for animals with large home ranges who might have trouble finding each other at the right time. The female may also be able to choose not to ovulate, if the male didn’t treat her right. See next point.

The girls are in charge

An analogy: All year a lady Koala will sit in her house as a happy single mother in her sweatpants, eating, watching TV and playing with her kid. But then October comes around, the weather improves, and the males start to sing to her. It awakens something. For another month she stays in her sweatpants watching TV, but she starts to think about doing her hair and going to the gym. By December she is fit and fine and ready for the town.

She packs her bags and goes on a little sex holiday. She can walk many kilometres. She goes straight to the house of the male she wants, sets herself up in the spare room and waits. She has no fear of being rejected – koalas are born gorgeous, and they know it. The male eventually figures out she is there (he has a lot of spare rooms) and goes to her. He stands propped against the door (tree). Now he’s got her, he’s not letting her go. Later that night he goes in the door (up the tree), singing. If she likes him, she won’t fight him - much. If she doesn’t like him she becomes vicious, slashing at his face with razor sharp claws.

I’ve watched several females fight off larger males. Lady koalas are not to be messed with. When she’s finished with him, she goes home to her TV and her sweatpants.