Reptile & Amphibian Forums

discussion), was apparently missed. And the "point" is not just about blacktails, but concerns most types of reptiles, INCLUDING and especially greybands.

I never said all those blacktails were hybrids, I repeated that many times. But I did say that we saw a true captive and it was as normal or as normal then some of the wild odd individuals we have seen. Then we saw one individual that appeared to look very much like a hybrid(Hughs pic).

Then many posted all manner of great pics of many variations of blacktails, which was great.

The ACTUAL point is, we really do not know what makes up or causes that variation. Do we? We simply call them normal because we found them in a normal way. We were told blacktails are blacktails. That is the real problem. And please concentrate on this, we go by what we were told. We really do not know if each and every blacktail is truely a blacktail or not.

What I pointed out is, hybrids are not that abnormal to the naked eye. They merely share some characteristics, some may be seen, others may not be seen to the naked eye.

We never test these odd animals to see if they are pure or not. You all, or us.

In recent years, several species of reptiles have turned out to be the product of hybridization between two other similar species. This has occurred with more then reptiles as well.

We simply go by the book, but the book does not know about every individual or every population. That is the problem.

While some here tried to play the devils advocate, you needed to consider, thats what I was doing. You all have not DNA tested or even keyed out these odd individuals, Have you? So in all reality, I have as strong a case that some could be hybrids then you have that they are not. In fact stronger, but only by the slightest degree, and that degree is, we have seen oddball individuals. That appeared questionable. Then some of you posted similar pics. Sirs, those pics support my views, more then yours.

For instance, one mentioned that low elevation blacktails are different. Yes, thats true, BUT WHY? is the question, low elevation blacktails commonly co-exsist with another similar species, while most high elevation blacktails do not. Of course not far from my house, Blacktails and cerbs co-exsist at high elevation.

The reality is, we do not know what caused blacktails to be different looking at low elevations. I could argue that not all low elevation blacktails are different, as we have them right by my house and they are fairly normal.(half a mile from my house)

We assume the low elevation blacktails are ligher or a different color because of a different type of habitat. The different type of habitat "may" indeed have allowed the lighter individuals to survive, but hybridization may have been the actual cause of the liter animals. Again, we do not know do we?

The next point is, we are suppose to question this, not accept all things because we read it. Or because its common. Science is suppose to question, not accept.

Most missed my view because they simply want to be confrontational. Most pick a side, and push other stuff to the other side. The truth is, there is no sides, the animals are the animals, it does not matter what we call them. What we call them, is only of interest and entertaining to US.

What I actually said about blacktails was, a captive produced blacktail hybrid and that pic HKM took, led me to question other individuals that I(we) had previously thought of as normal. I repeated many times, I do not know if these are hybrids or not, but with the information I just mentioned, they deserve to be questioned.

The funny part is, this is a discussion group and we are suppose to discuss, it does not mean you are suppose to draw conclusions. I know, I do not hold 99% of stuff on these forums are meaningful. But I do hold all things I actually see in nature as meaningful. Of course, that does not mean I understand all things I see, in fact, far from it. I personally think all of us understand very little of what these animals actually are.

I do think a few of the mohave/atrox we saw, were hybrids, but without pics, theres no support. If we find more, we will take pics and post them if folks are interested.

Truth is, I am far more interested in why greybands can be so variable. Any ideas to discuss? Happy New Year

I am gonna go with the eastern populations of graybands seem to live in less xeric habitat. I have not spent as much time out west as some, but I don't spend all my daytime out there sleeping, and look at habitat a lot. Also east to west we gain altitude, so again drier conditions prevail. Just my thought, Prey base seems to be the same,except there are more kangaroo rats? out west. I see the smaller mice running the cuts everywhere, but the bigger mice/rats seem to be from further west than Val Verde. I kinda liken it to the coachwhips out there. Why are they brown east of Val Verde, banded around Val Verde, red headed in deep south Texas, and pink further west?
I know that it doesn't account for the fact that you can find good blair's phase types out west, and good alterna phases in the east, but hey, I can only hope that the new areas opening up to us will allow more questions than answers, lol!
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Todd Hughes

Sounds to me like you've changed your mind. You were certainly leading me in the direction of thinking that what you've seen are hybrids, and then now you're saying that you were never saying that they were hybrids. It's almost like you want to make the statement but then don't want to take credit for it, whether that credit is positive or negative.

I still agree with Damon that many folks jump to the conclusion that the snake in front of them is a hybrid when that's really just conjecture and it probably isn't (given the small amount of DOCUMENTED hybrids)...

that without extensive genetic testing and comparison to the DNA of known (captive bred) hybrids, we just don't know one way or the other. It's all conjecture.

Damon's thinking seems to lean in one direction, Frank's in another-but both admit they don't know for sure, which to me is sensible.
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Brad Chambers

The Avalanche has already started-it is too late for the pebbles to vote....

"Damon's thinking seems to lean in one direction, Frank's in another-but both admit they don't know for sure, which to me is sensible."

I understand...

That's me-master of the bleedin' obvious

Tomorrow I'll explain that, as you go west, you find more alterna phase!
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Brad Chambers

The Avalanche has already started-it is too late for the pebbles to vote....

While we are all rapt in conjecture - could you explain to me how DNA testing would clear any of this up? Is there a verified species DNA data base from which we could use to draw conclusions from? Don't you think that these species would have many common alleles? DNA seems a useful tool in determining relationships between species maybe? But would there be some way to accurately determine interspecific cross with current knowledge?

Just asking.

In the past, chromosome morphology via karyotyping has yielded reliable and, so far, valid results in determining hybrid origin in diploid and triploid lizard species, as well as others. Could this be a route of discovery?

I guess I hope someone works on it. Although very interesting, it just doesn't concern me too much from a personal research perspective.

For me, I believe interspecific breeding happens all of the time. I also believe it very rarely results in diddly. But, I can't imagine it doesn't result in something every now and then.

As for the oddball variation we have all seen and discussed here lately - many populations exhibit a high degree of phenotypic variation, many are static. Within the variation observed, in my case, the great majority seems like just that - a weird diamondback here, and goofy grayband there, etc etc. Then there are the variants (note word choice) that, make me say "Wow, this sure looks like a hybrid." Who knows what they are. My curiosity says, why do I say this one looks like a hybrid?

As you have all said - none of us know.

HKM wrote:

"While we are all rapt in conjecture - could you explain to me how DNA testing would clear any of this up? Is there a verified species DNA data base from which we could use to draw conclusions from? Don't you think that these species would have many common alleles? DNA seems a useful tool in determining relationships between species maybe? But would there be some way to accurately determine interspecific cross with current knowledge?"

Of course they'd have common alleles, they're closely related, right? But none of this matters much to me b/c I've never really advocated the overly generalized "do the DNA" solution. Like you implied, it's not like there's already some database with which to compare...

Maybe the "chromosome morphology via karyotyping" is the answer...

I just think that there are less hybrids than some people think.

>>I just think that there are less hybrids than some people think.

That's how Damon and I got into the debate in the first place, plus it seemed he was discrediting my observations and my ability to identify an intermediate specimen.

So how many hybrids do people think are out there?
It's just as difficult to quantify that as it is to prove an animal is or isn't a hybrid.
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http://www.hcu-tx.org

"...plus it seemed he was discrediting my observations and my ability to identify an intermediate specimen."

I wasn't discrediting your observations... just questioning the conclusions you drew from them.

It may be that I'm the one drawing incorrect conclusions from my observations, but I have not yet seen evidence to sway my impressions. Finding an "odd" or "intermediate" specimen every now and again doesn't cut it for me. God knows I occasionally find an odd example of most every species that occurs in my herping haunts and I'm no less likely to consider them hybrids than the odd scuts/atrox/molossus in question here. In fact, I see enough oddballs of species with no opportunity for hybridization that it makes me less likely to believe in anything but a narrow hybrid theory when I find oddballs with sympatric congenerics or conspecifics.

I'm certainly intrigued by the topic and I'll certainly be going out of my way to take photos of animals I'd normally be content to inspect and let alone. Just what I need... more stuff to photograph!

well you didn't quantify anything there. The question is "how many are out there?". By a rough estimate the questionable animals I saw this year represent 1/6th of one percent. Is that the conclusion I reached that you are questioning?
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http://www.hcu-tx.org

You wanna know how silly this is? Think about this. What if ONE single solitary hybrid scutulatus x atrox male appeared and then bred another snake, atrox or scut? Now you take the math from there, and you tell me how hybrids are in the population after 20 generation. Can you breed it back out? I asked you how much genetic material is contained in one individual? How many generations?
Oh I know it sounds preposterous!

I'll finish it off something really profound. I think there are a lot of closed minded individuals on this forum. Hybridophobia for sure!
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http://www.hcu-tx.org

My question regarding your conclusion stems from the idea that an assessment as to the status of any given animal can be made by simply looking at it. I don't feel comfortable standing over an animal that appears somewhat novel and nonchalantly declaring it a hybrid. I give inherent variation and the myriad of localized pressures much more clout than that. You may think that close-minded, but until such a time where actual evidence can prove otherwise, I feel that the burden of proof is on those who feel hybridization to be anything more common than a rarity.

"You wanna know how silly this is? Think about this. What if ONE single solitary hybrid scutulatus x atrox male appeared and then bred another snake, atrox or scut? Now you take the math from there, and you tell me how hybrids are in the population after 20 generation."

You of course realize that there are a myriad of scenarios that would have to take place in order for your hypothetical to come to fruition. In a simplistic sense it would of course extrapolate out into ever-expanding areas of hybridization and large-scale introgression, but for me it assumes too much… a large number of concurrent breakdowns in naturally evolved barriers (adjusted reproductive seasons, pheromone incompatibilities, non-diminishing hybrid vigor etc.). Nature in my estimation tends most toward diversity. Each line continually looks for opportunities to split, adapt, split, adapt. While opportunities for consolidation present themselves it doesn’t seem to be the efficient and effective means to an end that adaptation, mutation, and diversification can be. While the idea of hybridization provides an immediate solution to the questions posed by the observation of an “intermediate” animal, it seems to ignore the more broad impression of an incomprehensively diverse genetic base and protracted temporal scenario that would have been required for the generation of the species in question in the first place. I obviously don’t feel natural hybridization to be an impossibility, just that it’s over diagnosed.

You think me close-minded for not acquiescing to your points but I can assure you… I have no “hybridophobia”. The empirical part of me just needs more than “I’m sure it’s happening” before I can jump on board.

PS. Post photos of your intermediates and let’s discuss what you’re seeing that I’m apparently not.

>>>>I don't feel comfortable standing over an animal that appears somewhat novel and nonchalantly declaring it a hybrid.

Who did that? Did you do that? I certainly did not do that. I think you nonchanlantly dismissed my observation. Given a point of reference for known hybrids (Aird et al) the animals I observed were more than likely hybrid. I maintain they were, you say they weren't. Pretty much end of discussion.

>>>>> I feel that the burden of proof is on those who feel hybridization to be anything more common than a rarity.

Well here you go again. No one has yet to quantify it, other than to suggest it might be more common than you believe, but you're still stuck on it might be less common than we think based on what you have not seen. hahahaha
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http://www.hcu-tx.org

"you're still stuck on it might be less common than we think based on what you have not seen. hahahaha"

I am basing my opinion on what I have not seen. You on the other hand have seen "it". I know you travel with a camera at the ready and certainly wouldn't overlook an opportunity to photograph something as uncommon as the fraction of a percent oddball. Just post pictures of what you have seen and we can discuss what we're both seeing.

>>"you're still stuck on it might be less common than we think based on what you have not seen. hahahaha"
>>
>>I am basing my opinion on what I have not seen. You on the other hand have seen "it". I know you travel with a camera at the ready and certainly wouldn't overlook an opportunity to photograph something as uncommon as the fraction of a percent oddball. Just post pictures of what you have seen and we can discuss what we're both seeing.

I only have a photo of one specimen that even could be considered iffy, not the best photo or specimen. Had I known we'd be having this discussion (hindsight is 20/20).

You might be able to get me to cop to "uncommon", but according to one expert on rattlesnakes, a hybridization is "normal and rarely has any major consequences for the species overall". Notice he didn't quantify it either. He's reading but I'll leave him un-named.

If you want me to agree to rarity, give me an example of other critters you consider a rarity.
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http://www.hcu-tx.org

I think it is rare compared to the number of same species breedings, example atrox to atrox and mojave to mojave is way more common than atrox to mojave, where they overlap. That said I think it is a very interesting theory(hybrids) and like Frank says; paraphrasing: If they can do it, at some point they will. I think hybridization could actually contribute to diversivication because the two species need not die out in all part of their ranges, for a third to emerge in a selected part.

>>I think it is rare compared to the number of same species breedings, example atrox to atrox and mojave to mojave is way more common than atrox to mojave, where they overlap. That said I think it is a very interesting theory(hybrids) and like Frank says; paraphrasing: If they can do it, at some point they will. I think hybridization could actually contribute to diversivication because the two species need not die out in all part of their ranges, for a third to emerge in a selected part.

Aaron,
I agree it is (rare, unusual, or uncommon) compared to same species breedings, and attempting to quantify it based on any other rarity isn't going to cut the mustard (bad idea for me).
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http://www.hcu-tx.org

That's ok. It was an interesting question and I guess it was relevant in the sense that it spoke to what our perceptions of rarity are. So it was statisticly irrelevant but perceptually very relevant, I think?

I know you've seen these Joe, but I thought everyone else might like to see them. These are the images from the Aird paper:

citation:
Venoms and Morphology of Western Diamondback/Mojave Rattlesnake Hybrids
Steven D. Aird; Luke J. Thirkhill; Corrine S. Seebart; Ivan I. Kaiser
Journal of Herpetology, Vol. 23, No. 2. (Jun., 1989), pp. 131-141.

captive F1 Maricopa Co., AZ atrox/scutulatus hybrid:

captive F2 Maricopa Co., AZ atrox/scut X scut hybrid:

Hey Damon,

I admire your skepticism. It is a very important character for science. I hope you truly combine it with a wide-open sense of wonder and possibility (I am not saying you don't already), for if you do - the sky is the limit. You defend your position eloquently. Whether I agree with you or not is of little consequence.

I wish I wasn't the senile ol' goat that I am and could remember meristic detail from the specimens I sent to UTEP so many years ago. Next time I am at that collection I will see if I can look at them and take a few photos of their head scales.

While I am on the subject of head scales, I would like to add another log to the fire just for the fun of it all.

I believe scutes and atrox are good species. I believe I can tell one from the other (at least the vast majority of the time ). But what if I couldn't? What if I found a good ol' normal one of either species but was unfamiliar with what it was???? Can anyone point me to any published source / key that definitively defines and separates C. atrox from C. scutulatus?

Hugh,
Thanks for the comments. I appreciate your measured, articulate, and pragmatic approach to the discussion. I enjoy the opportunity to exchange personal observations and ponder the implications. I would very much like to see the specimens you deposited at UTEP and if you happen to make it over there and manage to take some shots I'd very much like to get copies. This discussion and driven me to learn more on the subject and I'd be delighted to be privy to any of your photographs or observations.

As for your question regarding a published source or key that provides definitive delineation between atrox and scutulatus... I don't believe there's a sufficient one. The two species are similar in many regards and regional variation is large enough that some of the traits listed on commonly referenced keys (postocular stripe angle/termination point, tail band count/width) don't end up being helpful in local diagnosis. That's part of the reason I'm hesitant to believe all of the reports I hear of hybrid Crotalids (scutulatus and atrox particularly). There’s an opportunity for misidentification to enter into the equation and skew legitimate numbers.

"As for your question regarding a published source or key that provides definitive delineation between atrox and scutulatus... I don't believe there's a sufficient one."

You are right. There is not a sufficient one - nor is there for quite a few widely accepted rattlesnake species.

"There’s an opportunity for misidentification to enter into the equation and skew legitimate numbers."

I know I have excised your latter quote out of context, forgive me, and I understand what it was you said. But, for those of us that DO know these species, and have observed umpteen-hundreds of them range wide, we ID them correctly (as much as that is possible) without key or reference in hand. We do it out of a gestalt sense of understanding ALL (most? a lot ) of what makes a Mojave a Mojave versus other snake species. We don't key every specimen out to ID them. We also know that even with specimens that we are sure of their ID, that the keys will often fail to prove (I am intimidated by that word) one from another.

So for me, as I have stated previously, I am curious about the specimens that make me "gestalt" the idea of hybridization??? What makes me think hybrid when I see these guys? Where does that come from versus the way more common "that is an unusual looking scute, or atrox, or molossus, or insert whatever species you wish variant?" It is the same system of ID going on every time, one that I feel very confident in with these species. So when my brain occasionally says "hybrid", I listen, entertain the idea, consider the possibilities, and usually end up thinking that there is truly something different about this one. Then I get back to whatever field project I was supposed to be working on when the oddball beast in question momentarily steered me of course.

Damon - Maybe where we differ is where the line is drawn?

Cheers, Hugh

I think we may indeed be drawing our lines in different places... I may be willing to attribute a wider range of phenotypes to inherent variation, but I think we're actually not that far apart in our positions. My original comments surrounding the posts on Shannon's 118 atrox were rooted in my experiences with mostly Lampropeltis driven herpers who incidentally encountered Crotalids. They then, based I guess on passing conversations with other herpers who made mention of hybridization, seemed more likely to assign hybrid labels to animals they didn't know (and didn't really care) how to identify (they were also just as likely to completely misidentify one as the other). This over diagnosis left the impression that the scale of hybridization was more expansive than seemed plausible (in my opinion).

since we are on the subject, here are a few suspect animals from around here.

first is a viridis?? some think they have some lutosus in them as well but known lutosus are about 100 miles north of this locale?? I really don't know but there is also stephensi found side by side with these weird viridis.

another from same spot.

then there are the stephensi in eureka valley area that some people think are mostly hybrids with lutosus? this pair were collected both as babies 13 years ago side by side and the female is pretty common for the area but the male(grey looking one) is pretty weird.

Shannon

here is the one that didn't show up.

L8r Shannon

.

Shannon:

Where is that last one from? It's pretty typical oreganus.

Bob

just over the Inyo line on 9-mile. I also think its pretty typical but a few have told me otherwise. I really don't see any lutosus in them at all even the weird ones you and Brad and a few others have found there.

Shannon

p.s. the only ones I have seen (no It was before I had a camera) that looked like stephensi x lut's were out hyw 6 in Quen Valley at the base of Montgomery Pass.
I have seen a few out there that look like they are right between.

Shannon