MACROPOD (KANGAROO AND WALLABY) REPRODUCTION IS TRULY FASCINATING

May 16, 2016 8:03 PM

Did you know that kangaroos have a trifold vagina? And that as a result of this complex reproductive architecture, a kangaroo neonate emerges after only 28 days gestation, raw-looking, jellybean-sized, body essentially just a head, trunk, and forelimbs, from its mother's cloaca to climb up to her pouch? And that at this stage, the neonate can't suck, so when it finds one of her four nipples the nipple swells up inside its mouth so that it is stuck, remora-like, and can't disengage until its jaw develops further? (Post inspired by a fascinating conversation with mefite athanassiel)
posted by ocherdraco (24 comments total)

Did you know that kangaroos have a trifold vagina?

No, I did not know that, but now I have a new way to start conversations.
posted by Joe in Australia at 8:18 PM on May 16, 2016 [10 favorites]

I saw a kangaroo birth video in the second grade or so. It was fully as disturbing as the human birth we had to watch in our Miracle of Life class in fifth grade.
posted by Countess Elena at 8:27 PM on May 16, 2016

...now I have a new way to start conversations.
posted by Joe in Australia

Given your location it is likely your audience will already be aware.
posted by Pink Fuzzy Bunny at 8:31 PM on May 16, 2016

Wait does this mean that woman in Dead Ringers was a kangaroo?
posted by Dr Dracator at 9:19 PM on May 16, 2016 [2 favorites]

Given your location it is likely your audience will already be aware.

It's news to me and I'm an Aussie born and bred (I did know about the foetus doing the crawly thing though -- OMG)
posted by prettypretty at 9:21 PM on May 16, 2016 [3 favorites]

God, mammalian reproduction is horrifying.

or should I say, "Evolution, mammalian reproduction is horrifying"? Doesn't have quite the same alarmed ring tho.
posted by Eyebrows McGee at 9:23 PM on May 16, 2016 [3 favorites]

I know I saw a little red kangaroo bean emerging and crawling into the pouch on some PBS show as a kid. Maybe 3-2-1 Contact or something
posted by anazgnos at 9:24 PM on May 16, 2016

Well, what do you know, 3-2-1 Contact is exactly where I saw it.
posted by anazgnos at 9:26 PM on May 16, 2016 [6 favorites]

It seems less horrifying than in placental mammals, where a giant 9-month-old organism has to make its way out of some narrow opening... you probably wouldn't even notice giving birth to a jelly bean.
posted by dilaudid at 9:28 PM on May 16, 2016 [4 favorites]

Ugh, newborn marsupials are terrifying, like undercooked fetuses. The only thing worse is monotremes hatching. It's like a mammalian fetus coming out of an egg, where no mammal should be, so you get two kinds of cognitive dissonance at once.

_{I said that platypuses are hatched naked and fat last week and I was so wrong, you guys. So. wrong.}
posted by sciatrix at 9:30 PM on May 16, 2016 [6 favorites]

This is the best.
posted by aniola at 9:31 PM on May 16, 2016

That kangaroo totally noticed giving birth to its jelly bean; that was one of my favorite parts. Offscreen, it even pre-groomed its fur to ease the climb!
posted by aniola at 9:32 PM on May 16, 2016 [2 favorites]

I have a tri-fold wallet. Does this mean my wallet is a good visual example of a Kangaroo's vagina? If so, this opens a wealth of conversation-starting opportunities for me.
posted by InsertNiftyNameHere at 9:35 PM on May 16, 2016 [3 favorites]

The creepy other thing about platypodes is they have no nipples, so they just sweat milk out of their belly skin and let the babies lap it up.

But yeah, as a veteran of mammalian reproduction myself, I am definitely of the opinion that mammalian reproduction is for the birds. Even budding would be less creepy.
posted by Eyebrows McGee at 9:56 PM on May 16, 2016 [2 favorites]

Good heavens! It's like a fever dream from Geek Love (WHICH I AM COINCIDENTALLY READING RIGHT NOW). I can't decide whether I am horrified or delighted.
posted by janey47 at 10:09 PM on May 16, 2016 [1 favorite]

You know, macropods have it pretty good. Sharks have to deal with intrauterine cannibalism. Then there are the Kiwis (bird not New Zealander), who's egg is so big it's the biological equivalent of "a human giving birth to a fully formed four-year-old". Or all the species that just die soon after giving birth.

Mammal reproduction is horrifying, yes; that said? As soon as reproduction goes beyond "Okay, I'm going to release some gametes, let's hope they wander into your gametes somehow, and not worry too much about it beyond that" things go from wierd, to wierd and kind of painful, to the inspiration for "Alien".
posted by Grimgrin at 10:28 PM on May 16, 2016 [1 favorite]

So, basically, the kangaroo bean is already more competent than newborn humans, who can't move anywhere or do anything?

Asking for a friend.
posted by allthinky at 5:28 AM on May 17, 2016

Many years ago I took a course on reproductive physiology of zoo, laboratory, and companion animals. That was a semester well-spent, let me tell you!
posted by wintermind at 5:45 AM on May 17, 2016 [2 favorites]

MetaFilter: I can't decide whether I am horrified or delighted.
posted by Monochrome at 7:55 AM on May 17, 2016

Yes, I did.
posted by flabdablet at 8:34 AM on May 17, 2016 [2 favorites]

What's really cool, and not touched on in any of TFA, is the way that kangaroos can put an in-utero embryo's development on hold until they have the wherewithal to feed it; plus, the pouch can serve milk in two different flavours simultaneously (one for a developed joey, one for a newborn sharing the pouch).
posted by flabdablet at 8:45 AM on May 17, 2016

It is touched on! At least that first part. Baby #2 goes into stasis at 100 cells, just in case #1 bites the dust.
posted by aniola at 9:46 AM on May 17, 2016

Whoops. So it is.
posted by flabdablet at 12:29 PM on May 17, 2016

Not stated explicitly AFAICT: in harsh conditions where feed is scarce, that stasis can be maintained for months on end if necessary.
posted by flabdablet at 12:32 PM on May 17, 2016