Science Trivia Thread

[Admiral Yi]

Name a species of land animal besides homo sapien that sheds salt tears.

[Viking]

Name a species of land animal besides homo sapien that sheds salt tears.

Pigs?

[Admiral Yi]

No.

Full disclosure: I read this factoid about 600 years ago, back when grumbler was middle aged; there is one species the author mentioned which I distinctly remember, there's a remote possibility the author mentioned another which I have forgotten.

[frunk]

Do you mean elephants, as in emotional tears?  I thought most mammals could produce tears, which contain salt.

[Viking]

Reptiles and birds produce salty tears, usually only marine mammals produce salty tears. All animals with eyes produce tears.

Dogs?

[Admiral Yi]

Do you mean elephants, as in emotional tears?  I thought most mammals could produce tears, which contain salt.

Elephants was what I was looking for.

According to my book (The Descent of Woman) humans and elephants (and one more?) are the only land animals whose tears contain salt.  The author's theory was that humans (and elephants (and one more??)) adapted to the billion year drought in Africa by going part way toward becoming amphibians, then changing back when the drought ended.  Salt tears are very common in amphibians and sea birds, to regulate the body's salt level.

Regardless, the baton is in your hands.

edit: Right, might have been mammals Viking.  Still, no harm done.

[frunk]

What significant fact about horses moving did Eadweard Muybridge prove?

[Admiral Yi]

One hoof is always touching the ground?

[frunk]

Nope.

[Viking]

Do you mean elephants, as in emotional tears?  I thought most mammals could produce tears, which contain salt.

Elephants was what I was looking for.

According to my book (The Descent of Woman) humans and elephants (and one more?) are the only land animals whose tears contain salt.  The author's theory was that humans (and elephants (and one more??)) adapted to the billion year drought in Africa by going part way toward becoming amphibians, then changing back when the drought ended.  Salt tears are very common in amphibians and sea birds, to regulate the body's salt level.

Regardless, the baton is in your hands.

edit: Right, might have been mammals Viking.  Still, no harm done.

The Author of Decent of Woman is Elaine Morgan. She has no credentials and she has been advancing what is called the Aquatic Ape Hypothesis for 30 years now. It is wrong. The main problem is that our salt glands do not work the same way as marine mammals, they work like the salt glands of birds.

Here is a site which goes into this in some detail.

Salt glands
In the section on tears you'll find that AAT/H proponents claim tears in humans are a method of actively excreting salt in response to a saltwater environment, but in fact, tears are never hypertonic and cannot do what AAT/H proponents claim for them. Tears are, however, strongly hypertonic in regard to potassium and that does indicate what environment we developed in. That environment is terrestrial, not aquatic. The salt glands of terrestrial birds and reptiles are specialized for excreting potassium, unlike those of their marine relatives.

Some AAT/H proponents, most notably Elaine Morgan, have insisted that salt glands do not exist in terrestrial birds and reptiles. I must admit I find it discouraging that someone who is making up a theory with which they wish to supplant the past several decades of paleoanthropology does so little research before making such claims. This info is readily available.

Of course, it may be that it isn't simply poor research, since Morgan continued to make the "salt glands only in marine birds and reptiles" claim long after the facts (with refs and accurate quotes) had been presented to her (in several newsgroup posts which she replied to and so presumably read). She did finally say that she was dropping these bogus claims, but these are related to her claims that human tears and sweat are aquatic adaptations, and she and other AAT/H proponents still make those claims. As always, the "false facts" generated by AAT/H proponents are persistent, and so I feel the facts must be stated once again.

Are you sure you aren't talking about emotional tears rather than just salty fluid seeping from the eye socket?

[Viking]

One hoof is always touching the ground?

Horses do lift all feet off the ground while galloping:contract:

He proved that the stride length was twice as long as the horse from nose to tail?

[frunk]

Horses do lift all feet off the ground while galloping:contract:

He proved that the stride length was twice as long as the horse from nose to tail?

Your offhand comment is right, through the use of still photography he showed that horses do have all four hooves off the ground when galloping.  This was despite his contrary expectation.

[Viking]

Just bumping up this thread.

Apparently the question was mine, and I let the thread die... so the next question is


"One Horsepower in a car is definitively not the average power of one horse, so how was the horsepower defined?"

[Admiral Yi]

The amount of energy required to pull one kilo up a 45% slope.  Or something like that.

[Viking]

The amount of energy required to pull one kilo up a 45% slope.  Or something like that.

hint, the question is "how was" not "how is". Horsepower is not a nice little SI unit. This Unit predates SI or any other unit system.