I might add.... sure there “is” a locality /endemic range within species , but there is that “in-between” and always will be . And if in this case tortoises ...are not too far off within DNA makeup and fertility capabilities that can produce offspring....sorta makes ya wonder. WERE TALKING SCIENCE NOT ETHICS
To date I don’t know of a penguin x zebra cross.....It CAN'T happen.
JD~

(09-30-2012 03:53 AM)N2TORTS Wrote:  I might add.... sure there “is” a locality /endemic range within species , but there is that “in-between” and always will be . And if in this case tortoises ...are not too far off within DNA makeup and fertility capabilities that can produce offspring....sorta makes ya wonder. WERE TALKING SCIENCE NOT ETHICS
To date I don’t know of a penguin x zebra cross.....It CAN'T happen.
JD~

If it did happen, it'd sell better if we called it a "designer parrot"...or a "designer pony"...

We'll have to consult the Marketing Department, I suppose.

StudentoftheReptile Wrote:Good post, GTT.

I'm sorry...I cannot resist. I was watching Big Bang Theory the other night and this line seems applicable.

"Dennis, would you like some Aloe Vera? Because you just got burned."

BAZINGA! . Couldn't resist either!

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Terry Allan Hall Wrote:If it did happen, it'd sell better if we called it a "designer parrot"...or a "designer pony"...

We'll have to consult the Marketing Department, I suppose.

A "Zenguin"!

I obviously have nothing to add to this thread but I found it very interesting to read. ;P

I don't think they should do that, huh!?

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(09-26-2012 08:30 AM)StudentoftheReptile Wrote:  Half man, half horse's arse? Heck, I know some people who are 100% horse's arses!

lol

(09-30-2012 06:35 AM)MichiLove Wrote:  I don't think they should do that, huh!?

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(09-26-2012 08:30 AM)StudentoftheReptile Wrote:  Half man, half horse's arse? Heck, I know some people who are 100% horse's arses!

lol

(09-30-2012 02:14 AM)N2TORTS Wrote:  Ok ... I've tried so hard for a week..... to "zip the lip"

Oh No Terry…..you have a Hybrid dog ? ….Your going to ruin the world , the dog breeds , fish and birds! …don’t you know Hybrids are a NO NO …<sly grin> . It seriously cracks me up to see how many get worked up and their so called ethics on Hybrids. I wonder what their opinion would be on Human crosses…Oh wait were ALL homo sapiens so that’s ok …..right?

Technically any crossing of DNA is "hybridization." But when we use the term "hybrid," we are referring to an interspecific hybrid, i.e. an artificial cross that would not happen if the animals were free to choose their own mates.

A mutt dog is not a hybrid, because all dogs are domestic wolves in the same species and subspecies.

A mixed human is not a hybrid, because all humans are in the same species and subspecies.

Can't say the same for artificially induced hybrids between tortoise species that would never mate unless deprived of their own kind.

Quote:Yet I have never seen one tortoise , dog or animal, cause more havoc within their own species other than MAN ( it‘s gotta be in the DNA huh ? )

Well, we are the most intelligent animal on the planet - free to use that intelligence constructively or destructively.

Quote:…..and honest it would take hundreds of years to see if it really was a problem …. Just like what we try and compare to “ what’s supposed to be known fact today” . Your really think there is 500 years left here on Earth? …. REALLY?………..

Of course I do.

Quote:Another thing with this boundary line BS…….If your talking about 100’s of years back ….there were no “ LINES” then. Your example of boundaries….what you mean a river? …Mountain range? …. HA! ….Tribes from around the world have used the tortoise as a food staple and in ceremonies….. for ions . So try and imagine your fake African boundary line-……… Tort A on one side and tort B on the other ……ya invite me over for dinner , I want to bring something to share ….10 torts on a rope ( yes they were used by European Shipmates and explorers as a major food source…Easy to thread on a rope and hang for storage, also one heck of a cool dish , among other things such as spear heads from its shell. Anyhow….I show up for the BB-Q after crossing the river in my boat ….gotta hit the head , set my 10 torts on a rope down . Too much coffee that am ..Wait coffee wasn’t invented then yet either … ( ha ha ha ) longer than expected …come back to find 10 on a rope is down to 8 …..two of them escaped. Gosh darn …..I just introduced a tortoise on the other side of the river……within an other “species ONLY boundary ” <~~~made up name by Man. Two years later it mates with “ the other side of the boundary tort “ Wa La ! ,,,,, You have a hybrid !

Remember, anatomically modern humans evolved some 200,000 years ago, and we went through a bottleneck some 80,000 years ago. We left Africa only some 40,000 years ago, and humans arrived in the Americas only some 14,000 years ago.

Meanwhile, tortoise species diverged from each other millions and millions of years ago, due to dispersal, isolation from natural barriers, etc.

Sure, humans have an impact on our environment; we're animals, too. But we are unique animals - very unique - in that we have morality. We can actually stand back and evaluate what we're doing, and assess whether it is good or bad.

Now, I ask you: why would you want to jeopardize creatures that were finely honed over millions of years of evolution into their current, amazing form?

No Geo ... I wouldn’t change a thing ..Nor do I endorse it. I guess what more of the focus is ..." just how true" that animal is because we say so ? And your right species vs species is different ... maybe more of the focus is on "locality" such is in the redfoot debates. The river factor was ment to be in that analogy of Hybrids could and probably did take place all through out time, and like you mention when man was introduced to those areas things changed .... species crossed lines. So now in this century we are going to label an exact range on which breed is exactly from what area? I honestly don’t think that’s possible , until further research as mentioned can " trace" that sort of linage. A great example of a Perfect Race Tortoise would be the two Island Torts the Galapagos and the Aldabra....two untouched islands for 1,000 s of years with no intervention by man.

PS:... Where you stashing all these resources were going to need in 500 years~

(09-30-2012 08:52 AM)N2TORTS Wrote:  No Geo ... I wouldn’t change a thing ..Nor do I endorse it. I guess what more of the focus is ..." just how true" that animal is because we say so ? And your right species vs species is different ... maybe more of the focus is on "locality" such is in the redfoot debates. The river factor was ment to be in that analogy of Hybrids could and probably did take place all through out time, and like you mention when man was introduced to those areas things changed .... species crossed lines. So now in this century we are going to label an exact range on which breed is exactly from what area? I honestly don’t think that’s possible , until further research as mentioned can " trace" that sort of linage. A great example of a Perfect Race Tortoise would be the two Island Torts the Galapagos and the Aldabra....two untouched islands for 1,000 s of years with no intervention by man.

PS:... Where you stashing all these resources were going to need in 500 years~

Well, you certainly raise a fair point about two areas of uncertainty: 1) the history of a group of animals, and 2) how long it has been since they have been isolated from others.

Here's a great example with our own species. Humans and chimps are obviously very different now, but that's because we've been separated for about 6 million years. However, early on in the split, it seems that the two lineages still hybridized every now and then:

http://www.msnbc.msn.com/id/12836649/ns/...GiO0U2jw40

That couldn't happen now, but it was possible back then, because our common ancestor had not fully diverged yet. The same may be said when comparing any two groups of animals. Go back for enough, and they come from the same group. It's just that today, with our humanly powers, we can go beyond the kind of natural hybridization that goes in on early divergence, and force hybridization in lineages that are fully separated. I think that should be avoided.

As for distribution in the past, that's one of my favorite topics. For example, there used to be horses, camels, elephants, and lions right here where I'm sitting in Colorado, and may have been wiped out in part due to human activities. Getting back to tortoises, the Mexican bolson tortoise also used to be found north of the Rio Grande. However, since this was during pre-Colombian times, the federal government refuses to reintroduce them into national parks, like Big Bend NP, for example. Fortunately, wealthy conservationists like Ted Turner are willing to reintroduce them onto their own private property, as in New Mexico, where they're doing fine.

Now, when you're talking about the leopard and sulcata tortoises, I don't know how closely their ranges today reflect their ranges in the past. Perhaps they used to be more widespread, perhaps they used to be less widespread, I just don't know. Nevertheless, because they diverged so long ago, I don't think that is relevant to the question of whether they should be hybridized. They are so different, that they should remain separate.

We could look at other examples, too. We've already talked about how closely related all box turtles are, and how closely related all redfoot tortoises are (including cherry-heads). We could also talk about how closely related all Mediterranean tortoises are. Nevertheless, I still think it is worth keeping them separate, because our mixing them would probably not improve their fitness, and could reduce it.

Very well said Geo and great writing skills to boot …. ( both you and Mark are superb writers) Also a classy debate …..and Like I’ve said before your “ one smart cookie” With a lot of folks learning I’m sure!
I still wonder though if such a different species , than why are they able to produce offspring? I guess what drew my interests to them years back . I have herd of a radi x RF but no “ hard” proof. RFx YF common ….and much of the Leo’s today are washed genes…. Aren’t those different species ( that would have different DNA but produced offsprings) or in the Leo case sub species….?
Darwin once wrote … “No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species. Generally the term includes the unknown element of a distinct act of creation.”

JD~

(09-30-2012 12:19 PM)N2TORTS Wrote:  Very well said Geo and great writing skills to boot …. ( both you and Mark are superb writers) Also a classy debate …..and Like I’ve said before your “ one smart cookie” With a lot of folks learning I’m sure!
I still wonder though if such a different species , than why are they able to produce offspring? I guess what drew my interests to them years back . I have herd of a radi x RF but no “ hard” proof. RFx YF common ….and much of the Leo’s today are washed genes…. Aren’t those different species ( that would have different DNA but produced offsprings) or in the Leo case sub species….?
Darwin once wrote … “No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species. Generally the term includes the unknown element of a distinct act of creation.”

JD~

Thank you. You're a smart cookie, too. I think we're now getting to the important aspects of this debate, which are, 1) if these animals can hybridize, then why not let them? And 2) If we let them, what harm can come from it? Allow me to repeat one line from your passage above:

"I still wonder though if such a different species , than why are they able to produce offspring?"

The answer I would offer is this. In nature, small differences in DNA can have big effects. Using humans as an example again, we are very closely related to chimps and bonobos, and only a little more distantly related to gorillas (all well above 90% relatedness). But it's those small genetic changes that made us what we are today, and them what they are today. We walk erect, they don't. They're hairy, we're not. They have big brains, but ours are even bigger. And so on.

Let's look at deer. Mule deer and whitetail deer are closely related, but they are usually found in different habitats. There are some areas, though, where they may meet, and when that happens, there's a small chance they may hybridize. Bucks that are mule deer x whitetail hybrids tend to have "funny-looking" antlers, which are not quite like one parent species, and not quite like the other. Also, when they flee from predators, their locomotion is a bit "funny," too. So, even though they are viable, and ever fertile (!), it's rare for them to pass on their genes. Partly because they are not as good at running away from danger. Even if they do, though, the does of either species do not prefer to mate with them. Thus, these hybrid bucks are doomed to a life of bachelorhood.

Let's look at canids, like wolves and coyotes. These two species are very closely related - close enough that the red wolf, which was once thought to be a separate species of canid, turns out to originate from a hybridization event between wolves and coyotes, with no unique genes having arisen since then. So, although matings between wolves and coyotes may result in reduced fertility, they don't always. This can give rise to a new group, like the red wolf. In general, though, when wolves meet coyotes, they don't mate with them. Usually, when wolves find coyotes they chase them down and expel them from their territories. And if they catch up with them, they usually kill them. Curious, isn't it? Why wouldn't they mate? They are capable of mating, but they don't. On the contrary, because they tend to compete, coyotes usually avoid wolves, and if they don't, they might end up getting killed. Turns out this has to do with a phenomenon known as competitive exclusion.

Within a given species, mating results in some degree of interbreeding. Not everybody mates with everyone else, obviously, but enough mixing goes on to keep the species together as a unit. That is, to prevent evolution into another species. However, sometimes populations split up for one reason or another (migration, famine, drought, new landscape features, whatever). If the separation is short, then the two populations may get back together and continue interbreeding. In that case, no speciation will occur. However, if the separation persists, and the two populations remain separate for a long time (thousands to millions of years), then they will eventually start evolving in different directions. New colors or morphologies may arise, new physiological traits may evolve, and new mating rituals may appear. Then, depending on how long the separation continues, if they ever meet again, individuals from one population will probably not choose to mate with those from another, even if they are still genetically compatible to one degree or another.

This lack of compatibility could have more significance than just mating. The two populations may have just drifted apart, in which case hybridization probably wouldn't have an impact on fitness. However, there could be more to it than that: the two populations may have become adapted to new conditions since their divergence. So, for example, if the first population stayed where it's wet and the other population moved somewhere drier, then the two groups would be adapted to two different levels of moisture or humidity.

Now, here's the kicker. Let's say some individual from the wet-adapted species successfully mates with another from the dry-adapted species. The babies hatch, and they are healthy, and even fertile. However, they're not as good at living in the wetter habitat as the one parent, and they're not as good at living in the drier habitat as the other parent. So, they are more likely to die in nature, because they are not well-adapted to either niche. In other words, they may be healthy and even fertile, but they are not as fit, so their chances of survival are lower.

Let's look at this from the standpoint of each parent. In the case of the male, it's probably not all that important if he mates with the "wrong" female. Short of getting a bad disease (which we know can definitely happen), he doesn't have much to lose. It's just a million sperm out of gazillions. If the baby dies, it doesn't really affect his father's fitness, from an evolutionary perspective. But now let's look at this from the female's point of view. She has to carry eggs or fetuses around until they're ready to be laid or born. That is a big investment of time and energy. It's a good risk to take if she mated with a fit male from her species. However, it's a bad risk to take if she mated with a male from another species, even a closely related one. For the reasons outlined above, the offspring of that union would be less likely to survive or breed. For that reason, the female should not mate with a male from even a closely related sister species.

Well, that's about it. Sorry for the long post, but I hope I've explained why even closely related species that could mate with each other usually do not.

(09-30-2012 01:53 PM)GeoTerraTestudo Wrote:  

(09-30-2012 12:19 PM)N2TORTS Wrote:  Very well said Geo and great writing skills to boot …. ( both you and Mark are superb writers) Also a classy debate …..and Like I’ve said before your “ one smart cookie” With a lot of folks learning I’m sure!
I still wonder though if such a different species , than why are they able to produce offspring? I guess what drew my interests to them years back . I have herd of a radi x RF but no “ hard” proof. RFx YF common ….and much of the Leo’s today are washed genes…. Aren’t those different species ( that would have different DNA but produced offsprings) or in the Leo case sub species….?
Darwin once wrote … “No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species. Generally the term includes the unknown element of a distinct act of creation.”

JD~

Thank you. You're a smart cookie, too. I think we're now getting to the important aspects of this debate, which are, 1) if these animals can hybridize, then why not let them? And 2) If we let them, what harm can come from it? Allow me to repeat one line from your passage above:

"I still wonder though if such a different species , than why are they able to produce offspring?"


Within a given species, mating results in some degree of interbreeding. Not everybody mates with everyone else, obviously, but enough mixing goes on to keep the species together as a unit. That is, to prevent evolution into another species. However, sometimes populations split up for one reason or another (migration, famine, drought, new landscape features, whatever). If the separation is short, then the two populations may get back together and continue interbreeding. In that case, no speciation will occur. However, if the separation persists, and the two populations remain separate for a long time (thousands to millions of years), then they will eventually start evolving in different directions. New colors or morphologies may arise, new physiological traits may evolve, and new mating rituals may appear. Then, depending on how long the separation continues, if they ever meet again, individuals from one population will probably not choose to mate with those from another, even if they are still genetically compatible to one degree or another.

This lack of compatibility could have more significance than just mating. The two populations may have just drifted apart, in which case hybridization probably wouldn't have an impact on fitness. However, there could be more to it than that: the two populations may have become adapted to new conditions since their divergence.

Now thats what I'm talking about!......Great info on the entire post ~

JD~

I've had two questions since I first heard of these guys.

The first, are the hybrids like ligers/tigons where it matters who mom/dad are in terms of how they will turn out? For example, could a mixture of male sulcata to female leopard create an aldabra-sized hybrid because the 'growth stopping gene' gets shut off but a male leopard and female sulcata create hybrids similar in size to their parents?

The second, it appears to be much more difficult to raise an unpyramided leopard vs a sulcata... where do the hybrids fit in?

(10-02-2012 08:56 AM)chairman Wrote:  I've had two questions since I first heard of these guys.

The first, are the hybrids like ligers/tigons where it matters who mom/dad are in terms of how they will turn out? For example, could a mixture of male sulcata to female leopard create an aldabra-sized hybrid because the 'growth stopping gene' gets shut off but a male leopard and female sulcata create hybrids similar in size to their parents?

Probably not, since tortoises have temperature-dependent sex determination, as opposed to chromosomal sex determination. In other words, male and female tortoises can have the same genes. Not so with mammals, where females have two X chromosomes, and males have an X and a Y.

Quote:The second, it appears to be much more difficult to raise an unpyramided leopard vs a sulcata... where do the hybrids fit in?

I don't know. JD, any observations about this yet?

(10-02-2012 09:21 AM)GeoTerraTestudo Wrote:  

(10-02-2012 08:56 AM)chairman Wrote:  I've had two questions since I first heard of these guys.

The first, are the hybrids like ligers/tigons where it matters who mom/dad are in terms of how they will turn out? For example, could a mixture of male sulcata to female leopard create an aldabra-sized hybrid because the 'growth stopping gene' gets shut off but a male leopard and female sulcata create hybrids similar in size to their parents?

Probably not, since tortoises have temperature-dependent sex determination, as opposed to chromosomal sex determination. In other words, male and female tortoises can have the same genes. Not so with mammals, where females have two X chromosomes, and males have an X and a Y.

Quote:The second, it appears to be much more difficult to raise an unpyramided leopard vs a sulcata... where do the hybrids fit in?

I don't know. JD, any observations about this yet?

Well you guys ...great question ! .. I also believe its more of a tendency for Leo's to pyramid than Sullies. Rather Wild or Captive... I have seen both . " In the wild " and here at home. Anyhow , one of the Lep's for sure has more attributes of a Leo's make-up ex : Shell Shape, head size and legs...also scales are different and yes this particular one is slightly more pyramided than the other ...( now grant it my torts are treated like a 5month old baby with about 4-5 hours a day involvement taking care of them, Feeding , cleaning, yard work ..and just plain "gazing" at how amazing these creatures are. Of course this accounts for all 20+ in the collection at present.) So I know they receive the utmost care in diet and “water times” and housing . Development has been very interesting since I know they are kept and treated the same way. They are by far one of the most attractive " desert type torts" I have seen. Both are growing machines and have surpassed the white Leo in size and about half the age. Of the two, the more sullie one is also the brute of the two. Bigger in size and personality ....both to date have shown extreme transformations and the likeness of both of the species involved, as well as a pure joy to interact with . I told myself I wouldn’t share anymore pics of them ...because of all the harshness and comments made. The funny thing though .....is the folks who can’t stand the idea are the first ones' to open the thread and look! So rather people (Generalized) find it a " wrong doing " Human nature still puts the brain into overload and intrigues us when out of the ordinary things happen and " proof " it can happen. Rather being man made or natural .
Again for the record I did not breed /hatch these but acquired them at 3 weeks old ….and glad I did so~


JD~

(10-02-2012 05:32 PM)N2TORTS Wrote:  I told myself I wouldn’t share anymore pics of them ...because of all the harshness and comments made. The funny thing though .....is the folks who can’t stand the idea are the first ones' to open the thread and look! So rather people (Generalized) find it a " wrong doing " Human nature still puts the brain into overload and intrigues us when out of the ordinary things happen and " proof " it can happen. Rather being man made or natural .
Again for the record I did not breed /hatch these but acquired them at 3 weeks old ….and glad I did so~


JD~

I feel bad about this, as I am one of the ones to have jumped down your throat. As you know, I think hybridization is a bad idea. But you have them, you didn't breed them, and you care for them. Personally, and setting aside my regard for them as cute (if odd) tortoises, at this point I regard them as an interesting experiment. Not one that should really be repeated, but one that is valuable nonetheless. I, for one, hope you continue to post pix of your little hybrids and document how they're doing.