Survival of the Fattest:
fat babies were the key to evolution of the large human brain
SC Cunnane & MA Crawford 2003
Comparative Biochemistry & Physiology Part A 136
doi 10.1016/S1095-6433(03)00048-5

In the past 2 Ma, the hominid lineage leading to Hs evolved significantly larger & more sophisticated brains than other primates.
We propose:
the Hs brain was a product of having first evolved fat babies:
the fattest infants became, mentally, the fittest adults.

Hs babies have brains & body fat, each contributing to 11–14 % of body Wt,
this situation is unique amongst terrestrial animals.
Body fat in human babies provides 3 forms of insurance for brain development, not available to other land-based spp:
- a large fuel store in the form of fatty acids FAs in triglycerides,
- the FA precursors to ketone bodies: key substrates for brain lipid synthesis,
- a store of long chain poly-unsaturated fatty acids LC-PUFAs, particularly docosahexaenoic acid DHA, needed for normal brain development.
The triple combination of high fuel demands, inability to import cholesterol or saturated FAs & dependence on DHA puts the mammalian brain in a uniquely difficult situation vs other organs,
this makes its expansion in early humans all the more remarkable.

Fresh- & salt-water shore-lines provided
- a uniquely rich, abundant & accessible food supply,
- the only viable environment for evolving both body fat & larger brains in human infants.

On Tuesday, February 1, 2022 at 11:15:21 AM UTC-5, littor...@gmail.com wrote:
> Survival of the Fattest:
> fat babies were the key to evolution of the large human brain
> SC Cunnane & MA Crawford 2003
> Comparative Biochemistry & Physiology Part A 136
> doi 10.1016/S1095-6433(03)00048-5
>
> In the past 2 Ma, the hominid lineage leading to Hs evolved significantly larger & more sophisticated brains than other primates.
> We propose:
> the Hs brain was a product of having first evolved fat babies:
> the fattest infants became, mentally, the fittest adults.
>
> Hs babies have brains & body fat, each contributing to 11–14 % of body Wt,
> this situation is unique amongst terrestrial animals.
> Body fat in human babies provides 3 forms of insurance for brain development, not available to other land-based spp:
> - a large fuel store in the form of fatty acids FAs in triglycerides,
> - the FA precursors to ketone bodies: key substrates for brain lipid synthesis,
> - a store of long chain poly-unsaturated fatty acids LC-PUFAs, particularly docosahexaenoic acid DHA, needed for normal brain development.
> The triple combination of high fuel demands, inability to import cholesterol or saturated FAs & dependence on DHA puts the mammalian brain in a uniquely difficult situation vs other organs,
> this makes its expansion in early humans all the more remarkable.
>
> Fresh- & salt-water shore-lines provided
> - a uniquely rich, abundant & accessible food supply,
> - the only viable environment for evolving both body fat & larger brains in human infants.

Arboreal apes need lightweight bodies, hylobatids have SC fat, terrestrial hominins living in forests (with fat forest pigs) sleeping in shelters and armed with weaponry did not burn off their SC fat layer which was advantageous for sleeping on damp forest floor.

On Tuesday 1 February 2022 at 17:26:33 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:

> Arboreal apes need lightweight bodies, hylobatids
> have SC fat,

Gibbons need, and can afford, some
extra body weight -- for effective
brachiation. They also need the
insulation at night, not being social.

> terrestrial hominins living in forests (with fat forest
> pigs) sleeping in shelters and armed with weaponry
> did not burn off their SC fat layer which was
> advantageous for sleeping on damp forest floor.

That must be when hominins acquired
such good night sight, such sensitive
hearing, and such a powerful sense of
smell. And where their infants and
other young learned to be so silent,
both by day and by night.

It all begins to fit.

On Tuesday, February 1, 2022 at 2:48:06 PM UTC-5, Paul Crowley wrote:
> On Tuesday 1 February 2022 at 17:26:33 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
>
> > Arboreal apes need lightweight bodies, hylobatids
> > have SC fat,
> Gibbons need, and can afford, some
> extra body weight -- for effective
> brachiation.

Gibbons and spider monkeys are extremely lightweight for their total body size. If extra weight was beneficial, that weight would be located at the posterior, certainly not all over the body. Human gymnasts/acrobats have very little SC fat.

They also need the
> insulation at night, not being social.

They do not sleep in bowl nests like great apes, so they have very dense fur and SC fat. Great apes sleep alone at night and have very little SC fat.

> > terrestrial hominins living in forests (with fat forest
> > pigs) sleeping in shelters and armed with weaponry
> > did not burn off their SC fat layer which was
> > advantageous for sleeping on damp forest floor.

A sad attempt at sarcasm by a cubicle hound:

> That must be when hominins acquired
> such good night sight, such sensitive
> hearing, and such a powerful sense of
> smell. And where their infants and
> other young learned to be so silent,
> both by day and by night.
>
> It all begins to fit.

If you have had ever left your cubicle, you would be aware of the illusions that have trapped you in ignorance. Your neighbors with noisy babes have no predators, no reason for silence. They are merely competing with the tv for parental attention. Our senses are derived from a formerly arboreal diurnal lifestyle, nocturnal vision is costly and with little advantage to Homo sleeping in enclosed shelters. Humans lack pheromones so lost some obsolete olfaction. Human hearing is typical for primates, but is selected for human vocalization reception.

DD'eDeN aka note/nickname/alas_my_loves wrote:
> On Tuesday, February 1, 2022 at 11:15:21 AM UTC-5, littor...@gmail.com wrote:
>> Survival of the Fattest:
>> fat babies were the key to evolution of the large human brain
>> SC Cunnane & MA Crawford 2003
>> Comparative Biochemistry & Physiology Part A 136
>> doi 10.1016/S1095-6433(03)00048-5
>>
>> In the past 2 Ma, the hominid lineage leading to Hs evolved significantly larger & more sophisticated brains than other primates.
>> We propose:
>> the Hs brain was a product of having first evolved fat babies:
>> the fattest infants became, mentally, the fittest adults.
>>
>> Hs babies have brains & body fat, each contributing to 11–14 % of body Wt,
>> this situation is unique amongst terrestrial animals.
>> Body fat in human babies provides 3 forms of insurance for brain development, not available to other land-based spp:
>> - a large fuel store in the form of fatty acids FAs in triglycerides,
>> - the FA precursors to ketone bodies: key substrates for brain lipid synthesis,
>> - a store of long chain poly-unsaturated fatty acids LC-PUFAs, particularly docosahexaenoic acid DHA, needed for normal brain development.
>> The triple combination of high fuel demands, inability to import cholesterol or saturated FAs & dependence on DHA puts the mammalian brain in a uniquely difficult situation vs other organs,
>> this makes its expansion in early humans all the more remarkable.
>>
>> Fresh- & salt-water shore-lines provided
>> - a uniquely rich, abundant & accessible food supply,
>> - the only viable environment for evolving both body fat & larger brains in human infants.
>
> Arboreal apes need lightweight bodies, hylobatids have SC fat, terrestrial hominins living in forests (with fat forest pigs) sleeping in shelters and armed with weaponry did not burn off their SC fat layer which was advantageous for sleeping on damp forest floor.
>

Yes, so much for the "boreal" part of "aquaboreal"...