Human Babies

[TimbaLanD]

Why are human babies more vulnerable at birth compared with new born of other species? Human babes require constant care and attention all the time yet we are more intelligent than other species. This constant care is required for an extended time (YEARS)!!! Anyone has any hypothesis on this?

[CharonY]

Actually human babies are not more vulnerable than compared to a large number of other animals. Take puppies or honey bee larvae for example. Human development is a bit slower than that of many other animals though, as is its lifespan.

[Sisyphus]

No, we really are more vulnerable than other animals, and for a lot longer, too. (It's not a lifespan, thing, either. For one thing, humans don't live that long "in the wild." And second, look at giant tortoises and stuff. A relatively long lifespan is a requirement but not a cause.) This is true not in spite of our intelligence but rather because of it. Basically, we have extremely complicated brains that take a very long time to develop and become fully-functioning. That's probably why humans seem to be unique in their extremely high intelligence. There is a huge cost to our nifty brains, which, evolutionarily speaking, are simply not worth it for most animals. Something like a tiger or a fish can only make use of so much intelligence before the complexity of the brain becomes more burdensome than useful. We humans, however, have opposable thumbs, good vocal chords, omnivorous diets, and all sorts of useful goodies that mean we can take advantage of more smarts, and afford to pay the price of longer childhood periods.

[H2SO4]

it seems hard to believe us humans actualy made it to where we are today without being killed of earlier.

[ecoli]

it seems hard to believe us humans actualy made it to where we are today without being killed of earlier.

 

absolutely. I attribute this to our extraordinary ability to work together and develop tools that helped us vanquish anima; foes much stronger and bigger than ourselves.

[YT2095]

they`re not entirely defenceless either, ever heard a baby Scream and then watched your Pets run for cover!?

 

not to mention "Ripe" Diapers!

[Martin]

Why are human babies more vulnerable at birth compared with new born of other species? Human babes require constant care and attention all the time yet we are more intelligent than other species. This constant care is required for an extended time (YEARS)!!! Anyone has any hypothesis[/b'] on this?

 

sounds like you are opening it up to GUESSES as to what might be possible evolutionary explanations. I didn't read up on this but can offer HYPOTHESES----you have to check for yourself to see what you think is reasonable

 

 

1. human babies are actually born "premature" compared with some other mammals because of a large-head-birth-difficulty tradeoff

 

large head has an advantage, but leads to birth complications. one solution that evolution might favor is getting the baby out earlier----that has the cost of having to care for it more---but mothers dont die as much.

 

2. hardwire versus learned behavior tradeoff

one reason human babies cant be independent sooner is they are incompetent compared with some other mammal babies. there is not a lot of completely coded instinct.

the advantage of INCOMPLETE HARD WIRING is it leaves room for a lot of flexibility in learned behavior-----you gradually learn how to put all the bits of instinct together

 

because of more flexibility of learned behavior there can be an evolutionary advantage (in our case) of less comprehensive instinctual programming

 

3. upright posture feedback loop---related to point 1.

 

going upright means that from an engineering viewpoint the pelvis has to act as a kind of bowl to support the guts and also in the mother's case the unborn baby during pregnancy

 

this means that the pelvis bone does not work right if it has too large a birth opening

 

other mammals, quadrupeds like horses, that foal mostly one at a time (not like dogs that do mostly multiple litter) can have WELL DEVELOPED BIG BABIES because the skeletal opening can be plenty large

 

once you start going upright, then you have ARMS TO CARRY THE BABY with, so a feedback evolutionary loop develops that favors more premature birth, which you CAN cope with because of arms, and is SAFER for the mother who is a biped and so needs a decent pelvic skeletal support/

so it puts an advantage on having less developed less mature babies.

 

does any of that make sense?

 

just ideas:-)

 

you ask for guesses and speculations, you get guesses and speculations:D

[TimbaLanD]

Martin, I wanted to see what others had to say from their own point of view. I like your hard wired concept but I still find it difficult to get my head around the whole situation. Even a simple task of walking (I know its complex but u know what I mean) take a very long time to master for humans but some animals start walking as soon as they are born!!

 

I understand we have evolved over millions of years but is there still room for evolution?

[Skye]

It's pretty useful for grazing mammals to be able to move from birth because the herds are constantly moving. They don't have a den they return to every night that they can drop the kids off at. They are always looking for new pastures. It's mainly these animals (mostly ungulates) that are developed at birth. Most of the other things are pretty similar to us.

[Martin]

It's pretty useful for grazing mammals to be able to move from birth because the herds are constantly moving. They don't have a den they return to every night that they can drop the kids off at. They are always looking for new pastures. It's mainly these animals (mostly ungulates) that are developed at birth. Most of the other things are pretty similar to us.

 

just more speculation:

litter size also a factor that would evolve

maybe as a tradeoff with self sufficiency at birth.

 

these animals that have dens offering a safe refuge can have

larger litters of less mature---e.g. puppies born with eyes shut.

 

the grazing herd mammals more apt to have a single baby because they need it with its eyes open ready to walk on day one

 

offhand I can't think of a mammal that does things in a way analogous to humans in the sense that it has a DEN rather than living on the move, and at the same time normally does single births instead of litters.

 

must be an example, just can't think of one

 

I can picture evolution juggling all these factors and finding various strategies that work for survival