Reptile & Amphibian Forums

I totally forgot I had this website bookmarked.. some of you may have already been there. I found this information very interesting, especially the data on scale counts and foot variations between them. Also, it is quite informative in regard to their wild habitat.

http://bornova.ege.edu.tr/~bgocmen/leopardgeckos.html
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Marcia McGuiness
Golden Gate Geckos
www.goldengategeckos.com

i tried looking at it, but then a window popped up saying "error-can't find website"..lol

bornova.ege.edu.tr/~bgocmen/home14.html
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Marcia McGuiness
Golden Gate Geckos
www.goldengategeckos.com

they have been interbreed for over 30 years in captivity so you would never be able to tell if it was an actual subspecies. You can really see the difference in color and pattern with those pictures.
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0.1 Albino Leopard gecko
Coming Soon
1.0 ball python

Very cool Marcia...... The discription of E.macularius.afghanicus is way different than the description in the first link you posted..... Pretty interesting..... What do you think of this?????

There is some habitat info saying that one lives on some sany soil where the other avoids sand..... Seems like there may be somthing to some leos getting impacted and others not...... Any comments are welcome..... Might just make some more inteligent conversation......LOL.....

I am not a biologist or zoologist, so my understanding of this is somewhat limited. I think it is interesting the way the different "sub-species" appear to have adapted based on their geographical location and endogenus environment in this guy's field reports. I agree with previous posts and threads on this subject that it would be very difficult to make a distinct differential between them in regions where their populations overlap.

He has the E. angramainyu and E. turkmenicus listed as a separate taxonomic group, where montanus, fasciolatus, and afghanicus are Eublepharis macularius. I wonder if this classification is generally accepted.

As a breeder, the part that I find especially interesting is where it was stated that, "Tremper selected color variants for the pet trade that exceeded variations observed in the field", and that "the parental stock was from Pakistan", Tremper 1997: 16-17. I am curious how that would affect the general idea that these color morphs were 'developed' and do not occur naturally in the wild.
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Marcia McGuiness
Golden Gate Geckos
www.goldengategeckos.com

I think any mutations (i.e. albinism, patternless, or blizzard) are things that could very well happen in the wild, and most likely do...though not often, and most of those animals likely get killed pretty quickly. I also think any color morph like tangerine or variances on original mutations like lightening the color of albinos(or any difference from a wild animal caused by selective breeding) is just the exaggeration or minimization of normal wild traits.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

I think it might be alittle deeper than that...... But who knows...... Cant really tell until some REAL studies have been done...... Speculation realy isnt valid but the ideas and speculation is what starts the real studies......

I think the only way to get mutations (I mean an actual mutation that would cause a recessive allele for a gene...) that won't occur in the wild is with radiation or some sort of strange condition that most captive leos I don't believe are exposed to...The only other way to get a mutation that has no chance of occuring in the wild is to use genetic modification...and I dont' believe any of the current morphs are that either. Other than those couple of conditions, any mutation that happens to occur in captivity has just as much of a chance to occur in the wild...its just not likely that it would last long in the wild. Anything that's not caused by single gene variances (the recessive and dominant alleles) is caused by selective breeding...which basically slowly exaggerates or lessens the the traits of the original wild animals. If leos become as domesticated as dogs, you'll see just as much variation (assuming the genome of leopard geckos are somewhere near as elastic as that of wolves...lol) as is in dogs. There'll end up being huge ones, tiny ones, etc... If you look closely at dogs there's really only 3 or four basic coat colors...black, white, and brown. The actual color is determined by the influence of multiple genes...if you look at wolves, all of the same colors are present...just in different shades. They have the same number of bones, same basic structure (although it varies greatly...everything is basically in the same place), and very similar nutritional requirements. The key is that any traits that would have been lost in the wild have been selectively bred into dogs to make them look as they do today. Now don't go telling me I can't compare dogs to leos...lol...I'm just trying to make the point that you can't make any changes in a species that the wild animals do not have the capacity for it to begin with unless they are genetically modified or exposed to wierd radiation or smt...lol While domestic/long time captively bred animals (I wouldn't consider leos to be domesticated yet...they don't differ enough from the wild specimens...) may look very different from their wild "cousins" they still share the same basic genetic code, and don't differ all that much in the bare bones basics other than for a usual loss of hardiness. I'm not sure if any of that makes any sense...I have a hard time putting my thoughts into words sometimes...lol Let me know what you think of this strange rant...
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

mutations in DNA do happen naturally and randomly without exposure to artificial tetragenic substances...current evolutionary theory says that the biggest leaps in evolution happen not from pure selective breeding, but through mutation (beneficial mutations give that organism an edge). These "new" mutations should happen with the same frequency in natural and captive-vbred populations, but with captive-bred mutations that might be fatal in the wild can survive or prosper.

So yes it is true that you won't see mutations that COULDN'T possibly happen in wild, but that doesn't mean there will never be a new mutation that haven't occured in the wild.
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

I agree wholeheartedly with everything you just said...I never said anything otherwise...I was just simply stating that basically all mutations that occur (or at least have occured) are completely natural...the difference between evolution in the wild and domestication evolution (if that makes sense...lol) is that most of the changes in domestication are caused by selective breeding, and not mutations, while most of the changes that occur in evolution in the wild are due to mutations, as there is no selective breeding and the "fittest" usually tend to have the similar traits to each other.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

Mutations and the great leaps in evolution the allow (in nature) usually are most sucessful when the environment changes suddenly (in evolutionary terms)in some way- the mutation favors survival in the new environment. I recall seeing a PBS show where they illustrated this with a moth. The moths were all white, and the bark of the trees they were found on were white, but smoke from a coal plant turned the trunks black, and soon the white moths were getting eaten faster than they could reproduce. But a mutation occured and a moth was dark, it survived. Within mere decades the species as a whole became dark, with white moths being very rare. Of course this is lightning speed in evolutionary terms. Very interesting!

And evolution really is selective breeding. , though by natural selection rather than by a breeder LOL
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

I saw that show...and I've heard about those moths many times...lol I believe they're in England or smt like that right? Do you remember? There is a difference between selective breeding and natural selection. Selective breeding often takes traits that would never survive under any conditions in the wild and exaggerates them...natural selection on the other hand favors animals that survive best under current living conditions. Like the example of the moths for example...is natural selection and mutational evolution at its best! lol...dogs are an example of selective breeding...a chihuahua, pug, miniature poodle, etc etc...could never be something that would happen in the wild...or survive anywhere in the wild now (except maybe around people that have a lot of trash...lol). There is a distinct difference between natural evolution and "domestication evolution." One favors the animals best fitted to survive...the other is choosing animals for specific looks or functions regardless of how they could survive in the wild.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

Nature has different standards of selection than breeders...of course...it's still selective breeding though, if you define it literally...though the "selectors" are different

The moths were in England as I recall. It was an interesting show, wasn't it?

I love nature/science shows and PBS. I hate it when all that's on PBS is some weird music I have no interest in. They're doing all these music shows lately, folk music revivals and all-cello-all-the time...I guess someone is interested in that stuff. I like NOVA.
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

It is selection yes...I wouldn't call it selective breeding though...as no one is going and picking who is mating with who... I just don't like to connect the two modes of selection as the outcomes and mechanisms are entirely different.

Anyway...that moth show was interesting...I dont' generally watch PBS...I think it was something I saw in some class or something like that. I prefer to watch the discovery channel and animal planet. lol...that is when there's something good on and I'm not already watching the Simpson's or smt like that...hehe
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

btw...the only reason I'm awake at 1 am (tonight anyway...lol I'm up past 1 regularly...lol) is that I refuse to stop playing solitaire until I can win a damn game!!!!!!! lol I'm getting really frustrated...if any of the posts I'm making don't make sense I apologize...lol
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

well I just won...lol...I guess I'm gonna get going to bed now...I'll post again in the morning!...night!
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

It's only 11:21 here, I'm off to bed soon myself. Maybe I'll play some mah jong soliaire on my laptop, LOL
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

hehe...thanks...hope you did well at mah jong! lol
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

Gregg,
I know you are stuck on this impaction thing, but I don't think any wild leo avoids a perticular terrain because of impaction. I tend to think that impaction in wild leos is probably very very rare. I know you claim to have "cut open" preserved museum specimens and saw certain things, but I think you may have made assumptions as to what it was you really saw. Just because it had grains of sand in it's gut(caught in villi no less) it was impacted? Don't you think wild leos likely have some amount of soil in there guts at any given time?
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Bill DiFabio
Garden State Herpetoculture...website to follow...
Email Me
"The poetry that comes from the squaring off between,
And the circling is worth it.
Finding beauty in the dissonance." - Maynard James Keenan

Absolutly Bill..... How can someone argue that..... The intestinal track I look at were not cut open by me........ They were already done....... Cant actually mess with the wets in that way...... I was just looking at the description of their environment and it says they avoid sand...... I was just guessing that maybe there might be something to that...... Maybe some subspecies are more prone to impaction being that they are not "used to" getting some of that sand in their systems and some subspecies can tolerate it more because their system are set up to accomidate some sand...... Ofcourse this is just mt assumption....... Why are you so quick to think it is not valid or atleast not something that should be looked into?????? If the feet are set up alittle different in some subspecies from eachother (which makes me think that some subspecies developed this to move around better on certain terrains)then why would it be so hard to believe that the GI system may be set up differently?????
Gregg

It was also mentioned that the scalation was different also..... This is leading me to believe that they have and very well may still be adapting in other ways...... Ways that you cant see by reading your leopard gecko from the outside.....
Gregg

"If the feet are set up alittle different in some subspecies
from eachother (which makes me think that some subspecies developed this to move around better
on certain terrains)then why would it be so hard to believe that the GI system may be set up
differently????? "

Well, I'm just trying to think of it logically. When your talking about feet being a little different, your talking about morphology. Morphology is effected and a result of the external evironment. Maybe some subspecies avoid sandy areas because they can't walk (or run from predetors) on it as well as another subspecies. This would be a logical way or thinking about why some subspecies have been observed in sandy areas and some not. The GI tract(not track) is designed and has evolved to optomize nutrient procurement. So I can not logically see how one subspecies would be more prone to impaction than another. They both need nutrients, the both need the same nutrients in the same amounts, why would there digestive systems be different. They both need villi, and I'm sure they must be the same size...hence the same chances of impaction for both.
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Bill DiFabio
Garden State Herpetoculture...website to follow...
Email Me
"The poetry that comes from the squaring off between,
And the circling is worth it.
Finding beauty in the dissonance." - Maynard James Keenan

Lets not start the argument again!...lol If you are going to debate it...make sure to be nice about it...I'm gonna stay out of it...lol
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

Hey,
I think I'm being nice...at least no one has been called stupid yet...lol.
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Bill DiFabio
Garden State Herpetoculture...website to follow...
Email Me
"The poetry that comes from the squaring off between,
And the circling is worth it.
Finding beauty in the dissonance." - Maynard James Keenan

n/p
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

I just cant see how this could be ruled out by guessing...... If patterns and feet and scalation change why is it hard to believe insides change....... Animals adapt in lots of ways and it is not just externally...... There does not have to be a genetic deformaty of a gene to change something...... Why assume these types of changes have to be brought on by radiation or other out side influences....... It could just be regular evolution or even as simple as a "line bred" trate........ GI tracks can change within species....... It is a proven fact....... Different environments= different prey items and other things a species would have to adapt to when they have been separated and isolated....... Am I right??? I could be very wrong........ But there is really no way for someone to say it is impossible especially when there have not been any noted studies on this........ And I dont really feel I am grasping at straws here....... It is very logical...... Your thinking is logical also........ Maybe I think too much about things........And maybe you dont think enough (and no, that was not a crack at you....LOL)......... Not that that is a bad thing........ I guess I just want to know why things work not just how.......
Gregg

I didn't say things change just by radiation and whatnot...lol I was just saying that everything starts from the wild animals, and gradually changes to what domestic (I don't feel like saying whatever the heck it was I said before so I'm just gonna say domestic even though leos really aren't...lol) animals look like. This may include GI tracts...however, usually changes of that sort occur when there is a genetic mutation that allows an animal to survive better (extremely rare...but that's how animals evolve...beneficial mutations...or at least not harmful ones). The GI tract is a fairly consistent thing...slightly different but similar prey won't change how it will absorb things or the structure of it. Dogs have the same GI tracts as wolves and can survive on exactly the same food and in exactly the same environment (given they were raised that way of course....and of course a chihuahua wouldn't be able to live among wolves...but it could still eat the same things...in much smaller quantities...lol). Even temperament type things are fairly simple...Usually in nature the way things happen is the simplest way...in other words if it seems one way, it usually is. That's not to say that a lot of things are more complicated than they seem...but most of the time things are as simple as they look. It's much easier to think that the structure of an animals feet would make it avoid a certain terrain than to think that it knows its GI tract can't handle consumption of it when it eats or smt...I have no doubt that "domestic" leos are less hardy than wild leos, but that's just a matter of even some of the weakest surviving and breeding...as well as inbreeding bringing out harmful genes and traits. Also they are not introduced to many of the diseases and whatnot that wild animals are, and therefore resistance to certain things has surely waned. I see no reason to believe that the GI tract would have changed...it hasn't really even in species that have domesticated for hundreds of years (thousands?...I dont' remember...for some reason I can't think today...lol). I oculd go a lot more into domestication and what it effects and what it doesn't...but yeah......I dont' feel like typing that much...lol

...didn't I say I wasn't going to get into this one?....lol...oh well
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

If an animal lived in an evironment with no sand, and it for what ever reason branched off into areas with sand the the animals over years would adapt to living in sandy areas...... This includes feet and scales changing and also injesting things it did not have to deal with on the non sandy surface and vice versa........ Water monitor (V. salvator) on certain islands in indonesia are able to eat cane toads where as some of their cousins (V. salvator ssp) on other islands can not....... Explain that to me and tell me that is not the GI tract changing in some way........ There are a ton of other examples I just dont want to get into them at this time...... Maybe in another post.......LOL
Gregg

hmm...that's true...I was thinking in the other direction....if they started out on sand then moved to a place where there was no sand there would be no reason for the GI tract to change...however if they started not on sand then when some moved to sand there could be the possibility that only ones with very strong or healthy guts would survive, and through the generations it could tolerate sand better...I suppose that is a possibility...I was thinking the other way around for some reason...lol It is just a theory though...I'd be interested in knowing for sure what's changed....but I doubt that much research has been done.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

"Water monitor (V. salvator) on certain islands in indonesia are able to eat cane
toads where as some of their cousins (V. salvator ssp) on other islands can not....... Explain that to
me and tell me that is not the GI tract changing in some way.."

Ok, It is not the GI tract changing in some way. Do you honestly think that the subspecies that can eat the toads has a physically different digestive system than the ones that cannot(although I have never heard of this and would be interested in seeing a reference)? If this is the case, it is an adaptation in the form of a resistance to the cane toad toxin(assuming that is why one can eat them and the other not). This would be chemical in nature not physical. Do you think the digestive system of a corn snake is different than a kingsnakes? Kingsnakes can eat venomous snakes because they have evolved a resistance to the toxins...again chemical, not physical. Getting back to the whole reason this thread started, in what way do you think the GI tracts would be different in the two subspecies of leos. Can you state a hypothesis as to what differences there could be to reduce the risk of impaction in one sub and increase the risk in the other sub?
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Bill DiFabio
Garden State Herpetoculture...website to follow...
Email Me
"The poetry that comes from the squaring off between,
And the circling is worth it.
Finding beauty in the dissonance." - Maynard James Keenan

I agree with you Bill...resistance to a toxin really isn't related to the GI tract...other than the fact that that happens to be the way it enters the body. I actually didn't really read Gregg's example...lol I just read the rest of the post. I do think that there could be a slight change in the GI tract...but I dont' know how much of one...which is why I'd be interested in seeing something that would indicate changes of that sort.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

natural selection can favor or disfavor all kinds of individual differences and mutations in all kinds of body organs and even in behaviors. It makes perfect sense to me that characteristics that favor survival to reproductive age would gradually increase in a population that has migrated to a new environment, that's just adaptation through evolution.

There are infinitite examples of evolutionary changes in all kinds of body organs, from blood to brains. For a specific, obvious and dramatic example of evolutionary digestive system changes in reptiles, just look at the marine iguana of the galapagos...it developed salt glands that remove excess salt from its food...natural selection of a tendency to better tolerate ingestion of sand seems minor in comparison...
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

Although water maonitors are not "my thing" you can go to cybersalvator dot c0m and speck with either J. Adragna, Mark Bayless or Daniel Bennet....... You should know atleast two of those names....... They have all the material you would ever want to see....LOL........ No one has as much data on the species as these three...... Well anyway...... I have a few theories as to why or how it could be that some subspecies could deal with it better....... First the GI tract can shed more frequently in animals living on sand (which would be the more likely)...... Could be a larger GI tract in animals from sandy areas....... It could also be as simple as better intestinal contractions to help the sand or other substrates be passed faster...... No my comparison with V. salvator may not have been the best but look at it like there could be different enzyms to break down the toxin before it hits the blood stream........ And your kingsnake/cornsnake theory was not the best either......LOL Kings built up an immunity to the toxins so if they are bitten while killing a rattlesnake it wont die....... That is why they can eat venomous snakes and corn snakes wont....... Besides that a corn could eat a venomous snake if the where snake eaters and if it was dead already because snake venom is not a poison........ In other words you cant die or be envenomated if it is injested..... It needs to be injected dirrectly into the blood stream........ This is actually a very good post and everyone is being cool to eachother...... I wish all post were this nice......LOL....
Gregg

"First the GI tract can shed more
frequently in animals living on sand (which would be the more likely)"
I would imagine this would compromise nutrient absorption...would natural selection favor this?

" Could be a larger GI tract in animals from sandy areas"

This would leave less room for other vital organs...would natural selection favor this?

"It could also be as simple as better intestinal contractions to help the sand or other substrates be passed faster..."

Again, nutrient absorption compromised.

Gregg I guess we could go on for some time about this...What it comes down to is why does one subspecies SEEM TO avoid true sandy areas. We have to consider a few thigs here, Just because one subspecies was not observed on sandy ares, does not mean they are not there. This is the nature of field work, your not always going to see what you are looking for. Even so, the one subspecies that seems to avoid sandy areas, certainly has and ingests sandy soil in it's range. There is particulate matter all throughout the leos range, and it is likely regularly consumed and passed. Sarahs Marine Iguana example was a good one, but it really has nothing to do with a physically different digestive system. Green Iguanas(as do uromastyx species) also have the salt glands, they are just more specialized in Marine Iguanas. I'd be willing to bet that there digestive systems are physically the same as other herbivours(reptile).
I think this thread has spiralled out of the realm of Logical thinking. Greeg originally suggested that the GI tract of the 2 subspecies might be somehow physically or mechanically different and that is why one avoids sandy areas and the other doesn't. I just can't see how Natural selection would favor that type of difference especially among subspecies. I just don't think impactions are a real issue with wild loes enough for them to evolve any specialization.
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Bill DiFabio
Garden State Herpetoculture...website to follow...
Email Me
"The poetry that comes from the squaring off between,
And the circling is worth it.
Finding beauty in the dissonance." - Maynard James Keenan

I'm gonna have to agree with Bill on the nutrient absorption thing/organ space things. Why would something change to compromise the species because of a risk of something happening? This is a very interesting discussion...Bill you're getting a little mean there though...watch it...lol Anyway...I like the different points being brought up....although...I really dont' want to get into the venom poison thing....but venoms are poisons...not all poisons are venoms...but all venoms are types of poison. A poison is just any substance that produces harmful effects on a body (be it animal or human). Venoms are justspecific poisons that gets injected directly into the bloodstream. Poison is a term describing substances for thier effects...venom has harmful effects on the body...therefore it's poison, regardless of the way in which it enters the body. Anyway...don't want to argue about that...so that'll be the last I say of it. So back to GI tracts and evolution...lol I also agree with the idea that since the leos are still so closely related its not likely that anything internal would have changed substantially...including the GI tract. I'd use an example of domestic dogs or horses here...but they haven't been introduced to more harsh conditions than thier wild counterparts, so that wouldn't really be a good comparison...lol I'm not sure how quickly harsh conditions would change species internally...the closest example I can think of is mustangs and normal domestic horses. Wild mustangs have much more harsh conditions than domestic horses, and have become much more hardy than "farm horses"...but their internal organs have not changed in any way. This really isn't a great example though...since they haven't been there all that long in the whole scheme of things. I don't know how long the subspecies of leos have been separated....does anyone have any info regarding that? The longer the length of time the more likely it is that something may have changed substantially...however I still don't see how shedding the intestinal lining more frequently, a larger GI tract, or stronger/faster peristalsis would help leos more than it would be detrimental...so I find it very unlikely that any of those things would have happened. That doesn't mean that there couldn't have been other changes though. Anyway...I just got up a little bit ago and I haven't taken Foster out...he's laying on the bed staring at me...lol So I have to go do that...
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)

I don't think logic is the problem at all, it's the assumptions you each are starting out with which lead to different conclusions. If you're going to take the position that impaction is not a significant problem in wild even on sand, then adaptations wouldn't be selected for over other traits that enhance surviveability. If you take the position that it is a big problem, it would be. If you both are taking opposite positions on the mortality rates of leos on sand in the wild you'll never agree, because you would both be right IF your original assumption (that you disagree on) is wrong. Natural selection will favor anything that increased chances of survival. If a 5% or 10% wider intestinal tract causes a slightly bigger belly but increases the leo's chances of surviving in that new niche (sandy), and makes utilization of a new environment without competition from other leos possible, it makes perfect sense that those (or similar) traits would be selected for and that a subspecies could develop that is better suited to that environment and can take advantage of its resources. If there is an increased food supply in an area due to lack of competition, even a slight decrease in utilization of food could be selected for if it is outweighed by greater food supply. In fact any trait that makes the leo more suited to the new niche would make it more successful there, whether it's feet or color or the intestinal tract or whatever. Even small changes can make a big difference.
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

If you both are taking opposite positions on the mortality rates of leos on sand in the wild you'll never agree, because either of you would be right IF your original assumption (that you disagree on) is right.
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Sarah Stettler aka Starling
Sarah@stargecko.com
StarGecko.Com COMING SOON! Star Quality Leopard Geckos
Specializing in Hypotangerine Tremper Albinos

Very good points! I'm not really sure what to think as far as all this goes...I'd want more information before I made any more real assumptions on this stuff....lol Way to many variables to make assumptions based on one original assumption about sand.
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Christina

0.3.1 leos (soon to be 1.3.1!)
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-0.0.1 albino (supposed Tremper)(Spitfire)
-soon to be 1.0 tangerine rainwater albino
1.0 australian shepherd/cattle dog (Foster...although he was being fostered before I got him...that has nothing to do with his name...It's after the beer!...lol since he's australian and I'm a college student!)