The Pre-Menstrual Drop Bear: 5 Amazing Facts about Koala Sex

The Pre-Menstrual Drop Bear: 5 Amazing Facts about Koala Sex

The angelic 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, May 3, in their honour.

Fact #1. Female koalas have 3 vaginas

I’m sorry, what? The little devils….”

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.*1.

femaleKOALAReproductiveAnatomytext(OMG Imagine inventing a sex toy for koala girls.)

Fact #2. 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?

You want to see a close-up of that, don’t you?


Fact #3. Koala sex is voice-activated

Its 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.*2

Barry White, Louis Armstrong, Leonard Cohen and Nick Cave 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. The best way to see and hear this is on Echidna Walkabout’s Sunset Koalas & Kangaroos tour.


  • 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. In fact, koalas produce a deeper sound than their body should be able to, due to special organs in their throat. *2
  • Why: Low notes travel further, so these males have a wider audience.

Fact #4. Koalas ovulate only after they have sex

Koalas don’t waste anything, not even eggs!  They are ‘induced ovulators’: an egg is released after sex and fertilised by stored sperm. *3

Induced ovulation is not uncommon in the animal world. 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.

The first Drop Bear (*4) was just a pre-menstrual female koala in a bad mood.

  • 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.

Fact #5. The girls are in charge

The best way to explain this is through an analogy:

All year a lady koala will sit in her house as a happy single mother in her trackies, 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 trackies 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.

Watch this rare footage of koalas mating in the wild:

When she’s finished with him, she goes home to her TV and her trackies, and soon to be baby.

Koalas are just so damn interesting! Can you ever look at them the same way again?

This is why Wild Koala Day is so important. The how and why of all this behaviour is best seen in wild koala populations, which are declining at shocking rates all over Australia. To keep them, we are going to have to act on protecting forest. Now.

Find out more about Wild Koala Day.

So on May 3, Wild Koala Day:

PLANT a tree

PROTECT a forest

PHONE a politician

Or support an industry that is fighting for their survival – come on a tour that features wild koalas




*1. Johnson, S & Holt, W.  “The Koala (Phascolarctos cinereus): A Case Study in the Development of Reproductive Technology in a Marsupial” in Reproductive Sciences in Animal Conservation, (2014) Chapter 9 p. 175

*2. Charlton B (2011) quoted in

*3. Ellis, W & Bercovitch, F. 2011 “Body size and sexual selection in the koala” in Behavioural Ecology & Sociobiology Vol 65 (2011) p. 1230

*4. Drop Bear: a fictitious predatory koala that drops onto unsuspecting tourists from above. see Wikipedia


5 Amazing Facts about Koala Joeys

1. Baby koalas are called Joeys. All marsupial babies are called joeys – kangaroos, wallabies, wombats, tasmanian devils, possums & bilbys. The meaning/origin is unknown – it’s possibly just a diminutive used at that time for any small animal. Joey as a baby marsupial was first recorded in use in 1839.

The use of the word joey may have started with the word being applied for a British fourpenny coin. Politician Joseph Hume promoted the use of the fourpenny, thus the coin developed the slang name joey after him.


2. The first time you see a koala joey it is already 6 months old. Koala joeys are born as tiny naked creatures that don’t look anything like a koala. They move straight into the pouch, and remain unseen until they emerge at around 6 months old.

Actual emergence takes time. The joey first pokes his head out of the pouch at 5.5 months, and fully emerges at 6 to 7 months. By 8 to 9 months the joey becomes too large to get into the pouch, and spends all his time on his mother’s belly or back.

3. Koalas invented pro-biotics. Koala joeys eat ‘pap’ – a special substance produced by their mother that looks like poo and acts like a probiotic. It contains gut flora that the joey needs to process eucalyptus leaves. The mother koala produces it from her caecum (a special chamber in her large intestine) and delivers it from her cloaca, so though it looks a bit like poo, its not.

Pap is absolutely essential to a koala’s health. Wildlife Carers with orphaned koala joeys will frequently ask the wildlife care community for a postal delivery of pap from a koala mother – any koala mother will do, the closer the better but any is better than none. Imagine receiving that package of squishy green slurry in the mail!


4. Koala joeys are born out of their mother’s central vagina. Female koalas have three vaginas.

Why? Its complicated, and deserves a complete blog on the subject. Suffice to say that the two lateral (side) vaginae are for the passage of sperm to the uteri, and the median (central) vagina is for birth.

5. Koala joeys are born high in a tree. There is no danger of them falling to the ground – they are so tiny they get trapped in their mother’s fur. At birth a koala joey weighs only 1 gram – as much as a single sultana/raisin – and is only 2cm long.


It’s Koala Joey Season in the state of Victoria right now. All over the state wild koalas can be seen with joeys – hotspots are The You Yangs near Melbourne, the Great Ocean Road and Raymond Island, East Gippsland.

Echidna Walkabout runs the following tours to see koalas in the wild – with a high chance of seeing koala joeys each year from September to November:

Wildlife Journey 4 days

Great Ocean Road 3 days

Koalas & Kangaroos IN THE WILD 1 day

For more information contact:

Janine Duffy

T: +61 (0)3 9646 8249

Echidna Walkabout Nature Tours & Koala Clancy Foundation

A Miracle (Koala) Baby! The story of wild koala Misty

25th August 2015: While on Koalas & Kangaroos IN THE WILD tour Wildlife Guide Scott’s Whats App message came through to Echidna Walkabout Nature Tours base:
“K1 (Koala sighting 1) is Misty. K4 is her joey. Both high in a Yellow Gum. Joey is laying across her front”



It was followed by a torrent of whoops, woohoos and thumbs up as our whole Koala Research and Wildlife Guiding team celebrated.

Every year we see koala joeys, so why was this one so special? To explain we have to go back to January 2014, to a week of terrible heat. Four consecutive days over 41C (105.8F). By January 18th, the fourth day, koalas were suffering.

This photo was taken 18th January 2014 and shows the first time we met Misty. She was not a happy koala.

This poor young girl was sitting miserably in a waterhole. And she wasn’t the only one – six other koalas were on the ground over those four days, and another six were sitting in the lower third of their trees. This is an unusually high incidence of ground and low roosting.

Misty was found at 9.45am that day, sitting with her feet in the waterhole. She was checked five times over the next five hours and she barely moved. I came past at 2pm with a lovely group of people on a Koala Conservation Day for Locals. I was shocked by her look of hopelessness.

On this occasion I did something I would not normally do: I asked my volunteers to wait in the car, and I approached Misty with a water spray while they watched. I was hoping that my approach would make her spark up and climb a tree. It didn’t, and that’s when I really knew she was in deep trouble.

A wild koala does not welcome a close approach by a human unless they are severely injured or so heat-stressed they are in danger of dying. Basically, their knowledge of impending death is so great that their fear of humans is cancelled out.  Misty was at Stage 5 of the Koala Heat Stress Scale – read about that here: When does a hot koala need help?

So when you see that beautiful photo of Sam the koala being given water by the firefighter – don’t see an appreciative wild animal being helped by a person. See a dying animal that has no choice.

I sprayed the full bottle of water on her, standing back as far as I could and all she did was put her head up. I called Donna from Lara Wildlife Shelter and asked if she could take her into care.

My beautiful volunteers were absolutely quiet and didn’t leave the car all this time. I bet the iPhones and cameras were working overtime!

Misty stayed in care with Donna for 10 days. In that time she was weighed, thoroughly vet checked, and assessed to have nothing wrong with her. I was surprised – could a healthy young koala really be brought so low by a heatwave? Other, older koalas were still alive through this heatwave, without our help. But, interestingly, one joey was looking a bit flat too – maybe it is hard on the young?

She was released to the place she was found, healthy and well, late on 28th January 2014.


Throughout 2014 and 2015 we have seen Misty on and off. At first, she stayed near the little waterhole. Later she was seen moving close to Nova and Elizabeth’s home area. We were thrilled that she was staying around and looking so well!

Then suddenly, in August this year, we got that beautiful message from Wildlife Guide Scott:

“K1 is Misty. K4 is her joey. Both high in a Yellow Gum. Joey is laying across her front”


Not only has Misty survived her ordeal, she has thrived. She has done the greatest thing of all for koala conservation – she has produced the next generation. And we’ve been part of that.

We are very proud ‘grandparents’.


Update 2017: Misty’s first joey Lluvia, a male, thrived, and became independent at around one year old.  In July 2016 Misty’s second joey, Cuddles, a female, emerged from her pouch.  At January 2017 Cuddles is still with Misty but becoming increasingly independent.

Emma – Wild Koala of the month for August 2015!

August Koala of the month is Emma!

This dear little lady has been a friend since 29th March 2006 – can you believe that? 9.5 years!  Emma has been delighting international travellers for nearly 10 years.  Aren’t we lucky to know her?


We are not sure exactly how old she is, but in 2006 we thought she looked around 3-4 years old.  That would make her at least 12 or 13 years old now.


Emma has always been a small female, and has never been seen with a joey.  Though that sounds surprising, its not.  A high proportion of our wild females never raise a joey.  Of eleven females currently living in our main research area, only three have ever been seen with joeys.  A few of those females are new, so may produce young, but this has been the pattern over all of our 17 years of koala research, both in the You Yangs and Brisbane Ranges.


We are not sure of the reason, but we can’t just assume its chlamydia.  Though the You Yangs & Brisbane Ranges populations are Chlamydia-positive, the disease rarely manifests in any way we can see.  Chlamydia could be the cause, but it could be something else.  Or it could be normal for koalas to have a low birth rate in these habitats.


It doesn’t matter to us whether she is a mother or not – she is a valuable member of the koala community and we love her!

How everyone can help wild koalas…

How to help wild koalas – tip 1. Fight Climate Change in every way you can. Climate Change is the biggest danger to koalas, and all our wildlife. A recent study has shown that koalas die if forced to live at regular temperatures over 37 degrees Celsius. This finding is supported by our own research. In most of the places koalas live wild, these temperatures are becoming more common.

Even if you live in Europe or North America, your efforts to combat climate change do make a difference down here. So thankyou for everything you do!


Pat with baby Banjo on a hot summer day

How to help wild koalas – tip 2. Trees! We need trees! Native forest is precious and should be protected – we have already lost so much, we can’t afford to lose any more. Plant new trees too – if koalas have plenty of good habitat they will have a chance against climate change.

If you’re planting native forest for koalas, don’t just plant Manna Gum (E. viminalis). Plant what is suitable/indigenous for your area. Koalas need mixed forest, with plenty of choices. In the You Yangs their preferred tree is River Red Gum, but they must have Yellow Gum, Ironbark and Blue Gum as well – they use different species at different times of year. Cherry Ballarts, wattles, Grey & Red Box are used as well.

Even if your area isn’t naturally home to koalas, planting native vegetation will help koalas indirectly – everything is connected and by helping other species the ecosystem is stronger. Same applies outside of Australia. Look after your natural environment and you will help koalas.


Koalas don’t just use trees for food – they are roosting sites, lookout points, nest/bed, a way to get out of the heat or cold… This is Cloud relaxing in a Gum-tree fork.

How to help wild koalas – tip 3: Water! Yeah, we know – koalas don’t drink! Well, actually they do sometimes…. If it’s very hot, or they are old or ill, or if there’s been a drought they need water.

We’ve also noticed that large water bodies seem to attract koalas, especially in summer. Even if those koalas don’t drink from the waterhole, they seem to like the trees near it. Have you ever noticed how much cooler it is downwind of a lake on a hot day? Also maybe the trees around water are in better condition.

Here’s a picture of wild female Zelda drinking from a man-made dam after 12 years of drought. She was an old lady (15+years) but she lived another 1.5 years after this. Maybe it kept her going!

Many Aussies who live in the bush put out dishes of water for the birds. It’s fantastic! You might find a koala enjoying your water one day. Make sure the water is well away from the house, people and dogs – wild animals will only come near people when they are desperate. If you have a dam on your property and can keep it topped up in summer you might find koalas congregating around it!

Rainfall is the best sort of water though – and the only way we can make sure of that is by addressing climate change. So keep up all your good work in other parts of the world – you will help koalas too!


Zelda drinking from a man-made dam (waterhole) on a very hot day.

How to help wild koalas – tip 4: Slow down on the road! Koalas climb down out of their tree every day and walk along the ground to another tree. They do this at all times of day and night. Sometimes this means crossing a road – eek!

If you’re driving through forest, take it slowly and scan the roadsides for wildlife about to cross. We think that 80km/hour should be the maximum speed limit for highways through national parks, state forests and conservation areas, and less on minor roads.

If you see a koala (or kangaroo) beside the road, slow right down and toot on your horn before you get to it. The sound might make them act. If not, put your hazard lights on and drive slowly around them (only if safe), giving them as much space as possible.

If you see a koala in the middle of a road, park your car safely with hazards on, and making sure you are safe, get out and shoo them off the road. Your approach should make them move. If it doesn’t, try making more noise. Don’t try to grab them unless you know how to do it safely – koalas can defend themselves vigorously! Throwing a blanket over them is the only really safe way. If you can do this easily, there is a good chance that the koala is sick or injured. Call a wildlife carer, or the local vet.

Update from the Bush – a baby girl!

Here’s an update from our Koalas & Kangaroos IN THE WILD tour!

This is baby Moijerre. For years we have waited for a female joey we can monitor from birth through adulthood. And she might be the one!


baby Moijerre, safely sleeping in her mother’s arms

In 2006 we met koala Pat as a 1 year old joey, on her mother’s back.  Pat became independent, but stayed in her mother’s home range.  So for the next 6 years we were able to watch the interactions between mother and daughter, and then, (wow!) the family life of mother, daughter and 3 grandsons!

Until now, Pat has been the only female joey that we’ve been able to monitor in this way.  Others have been born, but on the edges of our research area, and we haven’t seen them enough to get the information we need.

We met Carninje, Moijerre’s mum, in 2010.  At first she was nervous of us and when she produced a baby, they both hid from us.  We’re not even sure whether that baby was male or female.  We called that baby Keyeet.  He/she was born around January 2011 and became independent in late January 2012 – but disappeared.  Maybe Keyeet found another home range nearby, but outside of our research area.


Carninje when we first met her, still nervous and trying to hide

By 2012 though, a change had come over Carninje.  She had accepted us.  She realised that our Koala Etiquette Rules meant that we always stay 10metres away from her, and that she can relax when she hears our tour groups approaching.  And the attitude of the mother affects the attitude of the child – so when Moijerre first appeared she was calm, relaxed and curious.


one of our first views of baby Moijerre

We have had the joy of watching Moijerre grow up!  She is now 1 year old and independent. The great news is, so far, she is staying near her mum.  Fingers crossed – we are hoping for a repeat of the beautiful  mother-daughter relationship we had with Pat & Smoky.

proud and beautiful!  Moijerre as a 1 year old independent young female

The primary purpose of our Koala Research Project in the You Yangs is to investigate long-term social behaviour in wild koalas.  Interactions between koalas of known relationship (mother/daughter, mother/son) are particularly fascinating because they might show a close link between related animals.  This kind of research takes many, many years but is critical to understanding and managing wild koalas.  We need this information desperately.  Koalas are becoming scarce in many areas, and their conservation is a high priority.

All this research is fully funded by our Koalas & Kangaroos IN THE WILD tour.  To learn more please come on this small group day tour – just by being there, you are helping us to help koalas!

Just in time for Mothers Day!

All the best from the Echidna Walkabout team – Janine, Roger, Caz, Jo, Martin, Bill, Paul, Mary, Donna, Mel, Brian, Scott and Kirby

In the Gum Trees, the Banjo sings again…

The banjo stirs the hearts of Australians in two special ways: AB “The Banjo” Paterson, writer of Waltzing Matilda and The Man From Snowy River,  sang the words that made us dream of the Bush, the Outback, the wild places of our great land.  That land needs sweet rain to make it live, and it is the song of the Banjo Frog that means rain.

Now the Banjo is singing again in the Bush near Melbourne.  A tiny new life, born to the joyous calls of Banjo Frogs.  He is Banjo the wild koala and he is the spirit of The Bush that Banjo Paterson wrote about.


His mother is Pat, a 10 year old wild female koala, living naturally in the You Yangs west of Melbourne.  His grandmother is Smoky, the reigning Queen of the Gum Trees.  His two older brothers – Pitta and Clancy – are 7 and 5 years old.  Pitta disappeared into the forest years ago, but Clancy moved 3km east and became a Social Media star!

How do we know all this?  Because all these wild koalas are part of Echidna Walkabout’s wild Koala Research Project.  Every one of them is monitored by researchers on eco-tours that run daily – the Koalas & Kangaroos IN THE WILD and Great Ocean Road 3 day tours.

Come soon, and you might be able to see some of Banjo’s family…  Or follow the happenings on Koala Clancy’s own blog, Facebook page or YouTube channel!