Heat improves bone density

[Primum Sapienti]

https://www.sciencedaily.com/releases/2020/09/200911093027.htm

"Many biologists are familiar with Allen's Rule, from 19th-century naturalist
Joel Asaph Allen, according to which animals living in warm areas have a
larger
surface area in relation to their volume than animals living in colder
environment. Indeed, a larger skin surface allows better evacuation of body
heat. "In one experiment, we placed newborn mice at a temperature of 34 °C
in order to minimise the heat shock associated with their birth. We found
that
they had longer and stronger bones, confirming that bone growth is affected
by ambient temperature," explains Mirko Trajkovski, Professor at the
Department of Cell Physiology and Metabolism and at the Diabetes Centre of
the UNIGE Faculty of Medicine, who led the study. But what about adulthood?

"Consistent epidemiological data

"By placing several groups of adult mice in a warm environment, the
scientists
observed that while bone size remained unchanged, bone strength and density
were largely improved. "

[littor...@gmail.com]

> https://www.sciencedaily.com/releases/2020/09/200911093027.htm
> "..."By placing several groups of adult mice in a warm environment, the

> scientists
> observed that while bone size remained unchanged, bone strength and density
> were largely improved. "

Not uninteresting, thanks, but only some incredible idiots who believe their ancestors ran after antilopes over the Afr.savannas keep confusing "strong bones" with "pachy-osteo-sclerotic bones" (POS) as in all incipiently aquatic tetrapods, incl. H.erectus, early Cetacea, early pinnipeds & still today's Sirenia.
POS bones (lot of calcium = heavy) were not only much too heavy for running, probably also brittle: ideally for slow+shallow diving (esp. in *salt* water), but very bad for running.
Every sensible PA knows by now that early-Pleistocene Homo simply followed the E.African-S.Asian-S.European coasts, google "coastal dispersal Pleistocene Homo PPT".

[DD'eDeN aka note/nickname/alas_my_loves]

Subarctic people (eg. eskimos) have relatively shortest leg bones, but I don't know about their bone density.

[Primum Sapienti]

https://pubmed.ncbi.nlm.nih.gov/16311425/
Ethnic differences in bone mineral density between inuit and Caucasians in
north Greenland are caused by differences in body size

[littor...@gmail.com]

> https://pubmed.ncbi.nlm.nih.gov/16311425/
> Ethnic differences in bone mineral density between inuit and Caucasians in
> north Greenland are caused by differences in body size

Yes, negligible compared to the difference between He & Hs.
Pachyosteosclerosis as in H.erectus is seen in all tetrapods that begin diving,
it disappeared in Cetacea & pinnipeds as they began diving faster & deeper,
it's still seen in slow+shallow-diving Sirenia.
Only incredible imbeciles still believe erectus ran after antelopes:
there's 0 doubt erectus frequently dived for sessile foods, most likely incl.shellfish:

It was my friend Stephen Munro (we wrote a lot of scientific papers together) who discovered the engraving in the Dubois collection in Leiden (he came from my home):
"Homo erectus at Trinil on Java used shells for tool production and engraving"
José Joordens ... Stephen Munro ... 2014 Nature doi 10.1038/nature13962
The manufacture of geometric engravings is generally interpreted as indicative of modern cognition & behaviour,
but is this innovation restricted to H.sapiens? and does it have a uniquely African origin?
Here we report on a fossil fresh-water shell assemblage from the Hauptknochenschicht (HKS "main bone layer") of Trinil, type locality of H.erectus (discovered by Eugène Dubois 1891).
In the Dubois collection (Naturalis museum, Leiden NL) we found evidence for freshwater shellfish consumption by hominins, 1 unambiguous shell tool & a shell with a geometric engraving.
We dated sediment contained in the shells with 40/39Ar & luminescence: max.0.54 Ma ± 0.10, min.0.43 Ma ± 0.05:
the Trinil HKS is younger than previously estimated.
Our data indicate:
- the engraving was made by H.erectus,
- it is considerably older than the oldest geometric engravings described so far.
This discovery suggests:
engraving abstract patterns was in the realm of Asian H.erectus cognition & neuromotor control.

[DD'eDeN aka note/nickname/alas_my_loves]

MV thinks that a freshwater clam etching is relevant to the difference between Innuit and Caucasian bone mineral density. Sorry Mr. Mermaid, we are not clams.

https://medicalxpress.com/news/2022-04-protein-muscle-growth.html
TAK1 in muscle growth and bone maintenance

[DD'eDeN aka note/nickname/alas_my_loves]

Does immersion in cold water reduce muscle growth? Probably.
https://youtu.be/xVc2Zk2Kwyg

[Primum Sapienti]

DD'eDeN aka note/nickname/alas_my_loves wrote:

Some bits here

https://pubmed.ncbi.nlm.nih.gov/28561302/
Bone loss, traditional diet, and cold adaptation in Arctic populations

https://www.sciencedirect.com/science/article/abs/pii/S1094695006603363
Ethnic Differences in Bone Mineral Density Between Inuit and Caucasians in
North Greenland Are Caused by Differences in Body Size

[littor...@gmail.com]

> >> https://www.sciencedaily.com/releases/2020/09/200911093027.htm

The same idiots who believe their ancestors ran after antelopes over the African savanna also believe Inuit are H.erectus...

[Primum Sapienti]

littor...@gmail.com wrote:
>
>>>> https://www.sciencedaily.com/releases/2020/09/200911093027.htm
>
> The same idiots who believe their ancestors ran after antelopes over the African savanna also believe Inuit are H.erectus...
>