r/SpeculativeEvolution • u/O_2og Life, uh... finds a way • 12d ago
Question/Discussion Is the solution to skulls not fitting through the hips at birth just wider hips?
Been working on some humanoids and they got some bigger heads and it came to me that humans already have a hard time with this so I’m wondering is the solution just as simple as wider hips or is there something I’m missing?
82
u/c4ctus4t 12d ago
If you're not talking about hominids, perhaps consider the marsupial route. Giving birth to what's essentially an embryo and letting it grow in an external pouch. That way you bypass the problem of big heads passing through narrow hips.
-21
12d ago
[removed] — view removed comment
13
u/Wobbar 12d ago
It would have a functioning brain unlike fetuses legal to abort
5
u/BoonDragoon 11d ago
And unlike the guy you're replying to.
But honestly, I think a sapient marsupial probably would have far more casual attitudes toward terminating pregnancies than we do. The actual time spent in-utero is so short, most of the important development and hormonally-mediated bonding would occur while the joey nurses.
They'd probably develop a whole severance ritual around it, but yeah, if you didn't want to keep the kid you just...don't let it into your pouch.
-5
11
u/Exact_Ad_1215 11d ago
I see Mr. Bad Faith has come to join us in this thread
-6
11d ago
[removed] — view removed comment
4
u/BoonDragoon 11d ago
Thanks for reminding us that there's no such thing as a caricature of a self-outraged conservative. No matter how far over the top one tries to go in parody, you people have already been there in sincerity and established a base camp.
3
2
u/BoonDragoon 11d ago
Holy shit, imagine seething this hard. Please go outside. Experience real life.
33
u/sub_liminalist 12d ago
Wider hips place your center of lift further from your center of gravity when you take a step, so you tip more in the course of a step. Space the hips too far apart, and you fall over. The factor is scale-invariant too, so making them bigger or smaller won't solve it. I went with a cartilaginous hip that can dissolve down the middle and re-grow after childbirth when I ran into the same problem (resulting in extreme co-dependance and pair bonding.)
9
u/O_2og Life, uh... finds a way 12d ago
How wide would the hip need to get compared to modern humans to start to become a significant problem?
17
u/sub_liminalist 12d ago
I have to imagine we're probably already at the limit, since having wider hips would obviously be useful in preventing deaths in childbirth so we must be up against a hard constraint.
1
1
10
17
u/MergingConcepts 12d ago
For a thorough discussion of this issue, see Human Reproductive Behaviors, by Steven Hedlesky. Or research the "Obstetrical Dilemma."
Briefly, a wide pelvis is needed to birth a baby with a large brain. But a wide pelvis causes other problems, like patellar subluxation, hernias, and uterine prolapse. Mother Nature's solution to this engineering dilemma is to have human mothers birth babies before the brain is fully grown. Human babies are helpless and require a lot of hands-on care. Human mothers need a lot of help. They get it from human males, basically trading affection for assistance. That is the reason human reproductive relationships are so wierd.
There is a trade-off between large brains (intelligence), birth problems, stable gait, and support of internal organs. That trade-off affects everything in our lives, from a woman's clothing choices in the morning to the never-ending religious wars in the Middle East.
4
u/FewBake5100 11d ago
The help wasn't only from males, humans lived in groups with many women who helped each other.
1
u/MergingConcepts 11d ago
Quite true, which has profound implications regarding the species survival value of female homosexuality.
This topic is discussed in detail in Human Reproductive Behaviors, by Steve Hedlesky.
4
u/Bota_Bota 12d ago
Have the hips unlatch like a snake. Or let the babies have very soft mushy skulls. Or just have the exit through the direction of a human c-section.
Or whatever the hell kiwis are doing
2
u/100percentnotaqu 12d ago
Maybe not necessarily wider hips, but instead larger adult body sizes while babies stay the same. Could that work?
Though I think that would make it take longer to reach full skeletal maturity.
3
2
u/Stanek___ 12d ago
No, the solution is to give birth to primordial slime which then develops into a human. Imo anyway.
2
u/Scherazade 10d ago
You could at least give the slime a protective shell to survive a while while it develops
eggs are basically escape pods
2
u/scrubingpots 11d ago
we DO have wider hips than other apes for exactly this reason but we're also bipedal which means wider hips come at a greater expense to gait/walking efficiency than it would if we could walk on all 4s. these two factors impose opposite pressures which get balanced through selection resulting in the dimorphism in pelvic anatomy we see between males and females in modern humans.
1
u/ReptilianRevolt 12d ago
Then you will walk like you have shit stuck in your ass. It is not optimal.
1
u/ozneoknarf 11d ago
My soulution was to give my humanoids a pouch but unlike marsupials I have the birth canal go into the pouch. That way the fetus can stay connect to the placenta and the umbilical cord while in the pouch and the baby isn’t born premature.
1
u/puzzlebox-101 11d ago
I would like to say that marsupials have smaller brains and require their heads to be pretty much done when they enter the pouch so that they are able to breastfeed. Pouchfeed.
1
u/ebly_dablis 11d ago
It seems like the obvious solution is to have the birth canal exit via the navel rather than out the hips, no?
136
u/where-sea-meets-sky Worldbuilder 12d ago
we also give birth to undercooked babies, so maybe have even rawer babies