https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807808/

"The ostrich Struthio camelus reaches the highest speeds of any extant biped,
and has been an extraordinary subject for studies of soft-tissue anatomy and
dynamics of locomotion."

"High safety factors suggest that bone densities and anatomy of the ostrich
tarsometatarsus confer strength for selectively critical activities, such
as fleeing
and kicking predators. "

https://www.calacademy.org/blogs/project-lab/ostrich-leg-bones

"Most birds have bones that have been adapted to their lifestyle in the air.
Their structure is hollow with an internal pattern of supportive struts
making
their skeleton much lighter than animals of similar size. If you cut a
slice out
of a bird’s bone it would looks a bit like a sponge. Since Ostriches do
not fly,
many of their bones are like our own-solid bone encasing a tube of marrow.
With such heavy legs it would be extremely difficult for an Ostrich to ever
take flight, but instead they have bones that can withstand pressure from
walking and standing. We see solid bones in other flightless birds like the
Emu and even some penguins."

> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807808/
> "The ostrich Struthio camelus reaches the highest speeds of any extant biped,
> and has been an extraordinary subject for studies of soft-tissue anatomy and
> dynamics of locomotion."
> "High safety factors suggest that bone densities and anatomy of the ostrich
> tarsometatarsus confer strength for selectively critical activities, such
> as fleeing and kicking predators. "
> https://www.calacademy.org/blogs/project-lab/ostrich-leg-bones
> "Most birds have bones that have been adapted to their lifestyle in the air.
> Their structure is hollow with an internal pattern of supportive struts
> making
> their skeleton much lighter than animals of similar size. If you cut a
> slice out
> of a bird’s bone it would looks a bit like a sponge. Since Ostriches do not fly,
> many of their bones are like our own-solid bone encasing a tube of marrow..
> With such heavy legs it would be extremely difficult for an Ostrich to ever
> take flight, but instead they have bones that can withstand pressure from
> walking and standing. We see solid bones in other flightless birds like the
> Emu and even some penguins."

Very interesting, but irrelevant as to why H.erectus & partially neandertals still were pachy-osteo-sclerotic, as some idiots who confuse POS with normal bones of most mammals want us to believe.
POS or pachyosteosclerosis (extremely thick & heavy skeletons, possibly more brittle due to an excess of calcium) in tetrapods is exclusively seen in slow & shallow divers, incl. all aquatic mammals initially:
all early Cetacea & pinnipeds had POS, and Sirenia still have POS.
Google "coastal dispersal Pleistocene Homo PPT" (+ refs).

On Saturday, April 23, 2022 at 1:24:00 AM UTC-4, Primum Sapienti wrote:
> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807808/
>
> "The ostrich Struthio camelus reaches the highest speeds of any extant biped,
> and has been an extraordinary subject for studies of soft-tissue anatomy and
> dynamics of locomotion."
>
> "High safety factors suggest that bone densities and anatomy of the ostrich
> tarsometatarsus confer strength for selectively critical activities, such
> as fleeing
> and kicking predators. "
>
>
> https://www.calacademy.org/blogs/project-lab/ostrich-leg-bones
>
> "Most birds have bones that have been adapted to their lifestyle in the air.
> Their structure is hollow with an internal pattern of supportive struts
> making
> their skeleton much lighter than animals of similar size. If you cut a
> slice out
> of a bird’s bone it would looks a bit like a sponge. Since Ostriches do
> not fly,
> many of their bones are like our own-solid bone encasing a tube of marrow..
> With such heavy legs it would be extremely difficult for an Ostrich to ever
> take flight, but instead they have bones that can withstand pressure from
> walking and standing. We see solid bones in other flightless birds like the
> Emu and even some penguins."

Should be obvious, yet some claim not so. Compare ostrich to hummingbird leg bone density. Which one sleeps in water? Neither.

littor...@gmail.com wrote:
>> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4807808/
>> "The ostrich Struthio camelus reaches the highest speeds of any extant biped,
>> and has been an extraordinary subject for studies of soft-tissue anatomy and
>> dynamics of locomotion."
>> "High safety factors suggest that bone densities and anatomy of the ostrich
>> tarsometatarsus confer strength for selectively critical activities, such
>> as fleeing and kicking predators. "
>> https://www.calacademy.org/blogs/project-lab/ostrich-leg-bones
>> "Most birds have bones that have been adapted to their lifestyle in the air.
>> Their structure is hollow with an internal pattern of supportive struts
>> making
>> their skeleton much lighter than animals of similar size. If you cut a
>> slice out
>> of a bird’s bone it would looks a bit like a sponge. Since Ostriches do not fly,
>> many of their bones are like our own-solid bone encasing a tube of marrow.
>> With such heavy legs it would be extremely difficult for an Ostrich to ever
>> take flight, but instead they have bones that can withstand pressure from
>> walking and standing. We see solid bones in other flightless birds like the
>> Emu and even some penguins."
>
> Very interesting, but irrelevant as to why H.erectus & partially neandertals still were pachy-osteo-sclerotic, as some idiots who confuse POS with normal bones of most mammals want us to believe.
> POS or pachyosteosclerosis (extremely thick & heavy skeletons, possibly more brittle due to an excess of calcium) in tetrapods is exclusively seen in slow & shallow divers, incl. all aquatic mammals initially:
> all early Cetacea & pinnipeds had POS, and Sirenia still have POS.
> Google "coastal dispersal Pleistocene Homo PPT" (+ refs).
>

Ostriches are bipedal runners.

Somebody:

> Ostriches are bipedal runners.

Yes, my boy, ostriches are bipedal runners...
:-DDD
Ostriches don't have POS.
POS or pachyosteosclerosis (extremely thick & heavy skeletons, possibly more brittle due to an excess of calcium) in tetrapods is exclusively seen in slow & shallow divers, incl. all aquatic mammals initially:
all early Cetacea & pinnipeds had POS, and Sirenia still have POS.
Google "coastal dispersal Pleistocene Homo PPT" (+ refs).

On Friday, May 13, 2022 at 12:23:26 PM UTC-4, littor...@gmail.com wrote:
> Somebody:
>
> > Ostriches are bipedal runners.
>
> Yes, my boy, ostriches are bipedal runners...
> :-DDD
> Ostriches don't have POS.
> POS or pachyosteosclerosis (extremely thick & heavy skeletons, possibly more brittle due to an excess of calcium) in tetrapods is exclusively seen in slow & shallow divers, incl. all aquatic mammals initially:
> all early Cetacea & pinnipeds had POS, and Sirenia still have POS.
> Google "coastal dispersal Pleistocene Homo PPT" (+ refs).
Hummingbirds do?