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What are the known WDB hybrids, besides the common EDB X Wdb? What else can the becrossed with in captivity. Also are there any "natural" hybrids occuring in the wild?

As far as naturally occuring hybrids with C atrox the most common would probably be with C scutulatus. I'm sure it's not a common occurance but it happens from time to time here in AZ.
Hybrids with C mollosus have occured in captivity and I would guess that someone has also bred them to C. ruber as well. Those would be the one's that come to mind. I'm not sure about atrox X viridis. It might be possible where they overlap in New Mexico but it's a push.

Do you or any one have links or pictures of atrox X scutulatus? do you also have any leads to scale count information of the crosses or of either speices? Thanks for all your guys help... Hmm another thought is size ratio of the snake compaired to rattle count.. I know that one cannot tell age from rattle beads but since the scutulatus are smaller species than atrox it seems likly that they will have more rattles for thier size than atrox's?

I saw a thread a while back about WDB x Mojaves. Just a note. I never saw a pic.
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Peter: It's OK, I'll handle it. I read a book about something like this.
Brian: Are you sure it was a book? Are you sure it wasn't NOTHING?

....of hybrid wdb X scute.

atrox X molossus from west Texas.

Nice photo. This seems to be a fairly frequent cross in many areas too. I have seen them in Texas, Arizona and Mexico.

It also seems to me, that where you see crosses in the wild, you see them fairly regularly. I wonder if that is a factor of herping frequency or actual occurrence, ie, it is not uncommon for these species to interbreed where they are sympatric.

I agree, interbreeding does seem to common to particular areas. One thing that many of these areas seem to have in common in my opinion is a history of overgrazing.I think our interference with nature often breaks down barriers that would usually keep certain species apart. Overgrazed areas not only seem to produce frequent hybrids, but these crosses then breed back to each other producing many different levels at which the hybridization is obvious. I think the area near Big Bend you pointed out would demonstrate this at it's most extreme. I never realized there was so much hybridization in this area, but I do know I have seen what I thought to be an unusual amount of strange scutulatus "morphs" there over the years. I never had a clue about the atrox.

Crosses seem to occur less frequently in areas that are not subjected to cattle grazing. It also seems to me that scutulatus seem to be particularily prone to cross-breeding with other species, both in the wild and in captivity.

Yes the Big Bend area has certainly been ravaged by overgrazing over the last several decades, and let's not forget the goats that have finished off what was left after the cattle.

The atrox X scutes down there I literally stumbled on by preserving roadkills. In the early 80's, I sent some twenty D.O.R. atrox looking beasts off to University of Texas El Paso, and one of them caught my eye as being unusual pattern wise. Upon closer inspection I found the intermediate scale counts. When I sent them off I labeled them Crotalus sp? The collections manager, who was a friend, laughed at me and asked if I couldn't ID an atrox after all of these years? I called him and said to run them all through a key before he got too jolly about it all. They accessioned them all as crosses.

Very interesting thoughts about overgrazing.... I'll have to chew on that one for a while...LOL. There was a report in the journal of herpetology of a willardi X lepidus wild caught from the peloncillos several years ago. Interestingly, that area is heavily grazed too????

I'm definately going to have to look much more closely at them critters next time I'm down there!

I'd heard about that willardi X lepidus from the Peloncillos. Didn't someone try to describe it as "Crotalus apache"?

I have not heard of the attempt to name it Crotalus apache??

David Barker et al from UT Arlington put out out the paper, I believe in J. of Herp., I am guessing at least ten years ago?? I have it somewhere if you want the exact reference.

I just remember hearing through the grapvine that a new crote had been recently found in the Peloncillos and was probably going to be described as C. apache. Later I heard that examinations of the snake by other parties determined it to be a willardi X lepidus cross. I'm sure the story was re-invented a little with each telling before it ever got to me, lol.

although it was very obvious that it was a hybrid when viewing it in person it unfortunately didn't show as well in the pics.

I think this animal may be a hybrid as well. It was picked up on a call and later released but I took a few pics of it.

What do you mean when you say "picked up on a call"??

The Arizona Herpetological Association (AHA) here in Phoenix has a reptile rescue hotline which picks up unwanted animals from peoples yards and homes. This snake was on someone's front porch and would have ended up being killed had it not been picked up and released else where.

Thanks for the explanation. The fire departments do that around Tucson. Some follow very stringent capture and release guidelines that are very snake friendly.... others not so much.

Tucson Herp society was involved in assisting the fire departments who do it well.

Drexel Heights will be able to form it's own herp society!

Yes, we are a secret herpetological uprising in the making!!

I'm sure you remember the old days when the only one who would respond to snake calls was PCSO, they always used to have a few rounds of birdshot on them just for that purpose.

Yes the service has come a long way indeed. We offer to any other interested fire departments our operating guideline on evaluating, and if necessary, relocating snakes. We will also go explain how we do it, why we do it and train them on proper handling as well. The desert museum very kindly takes part in many of these fire department training sessions along with Drexel Heights Fire personnel and we feel it has been well received for the most part. It is still in its infancy, however, and time will hopefully continue to tweek it towards an even better system down the road.

This is interesting! When I'm out west I usually simply follow the Buzz Ross Rule on the coloration of the basal rattle segment (here in south Texas we don't have the hybrid problem!). Did you happen to notice the coloration of the basal segment on this snake? I agree that, from the photo, I would have called this snake an "atrox" without a second thought. What led you to recognize it as a hybrid?

Did you notice on BPO's photo below that the basal segment is both black and white!

Tom Lott

Actually I am the one who pointed out that scutes often have a bi-colored basal segment to Buzz,lol. I don't recall the color of the basal segment on the snake in the photo. The scute influence was determined completely by head shape which was VERY non-atrox. My cousin and I have found a number of scute X atrox crosses in this area. They always have the general appearance and color of an atrox. It's in the head shape where it is first recognizable. Some display the scute scalation of two large scales between the supraoculars and some don't. A few years ago I started pointing out certain snakes and saying their heads weren't right. I was told I was nuts. It wasn't until I found one with a very scute shaped head and the two enlarged scales between the eyes and placed it next to a normal looking atrox from just down the road that I was believed. The snake in the photo was odd because it was definately GREEN in the headlights. From a distance my cousin and I both said "molossus" unanimously. As we got a little closer we said "atrox?" unanimously. Then the snake turned just right giving us a good view of the top of the head and we both said "hybrid!" in unison.

Rich,

That's really interesting. I thought that someone had addressed this issue (in W Texas) a number of years ago (Journal of Herp?), concluding that the "persistent rumors" of scute X atrox hybrids was unfounded; that they only really, really resembled each other in that area!! LOL!!

I admit that I have found a few snakes in W. Texas that I couldn't call one way or the other. Based on what you say, however, I'm fairly certain that they were hybrids. The idea that the hybridization is connected to overgrazing definitely (IMO) holds merit and should be investigated further. Thanks for the detailed response.

Tom Lott

Hey Tom.....I never even bothered to look at the coloration of the basal segment. What is the "buzz" rule of thumb in re: to basal seg. coloration?

I still don't know what to call that snake.

Brendan

Brendan,

The basic idea is that in atrox the basal segment is completely black. In scutes, it is lighter, usually uncolored or mixed. This is usually the first thing I look at in W. Texas, NM, and AZ snakes. Your snake seems to scream hybrid, based on this character. Nice shot also.

Tom Lott

That Rich fella never told me that one. He did say something about the supraorbital ridge on scutes having a white outline though. I looked back at a few pure scute pics and he was right. He knows a lot more about snakes then he does about computers. LOL

that seems to hold true but only time and a larger sample size can demonstrate this for sure. A couple months ago Brendan and I were using photos on the AHA forum to try and show some youngsters the characteristics that separate atrox and scutulatus.I happened to notice that scutes seem to have a white or at least light colored outline on the outer edge of the supraoculars that atrox seem to lack. We immediatly went through every pic we could find and it seems to hold true. I spent a week in Aug visiting Buzz and we spent some time helping Jim Harrison obtain scutes for the breeding/venom production program at Kentucky Reptile Zoo. It held true for every scute and atrox we found in Presidio, Culbertson and Davis counties.

Here's a close up to illustrate your point.

....of that snakes BS

Here's that black b.s. of the atrox just like you said.

Your right...The mojave's BS has much less black.

I'm just figured out that you can no longer post multiple photos in the same thread. I guess I wasn't just you Rich. Is that something new for KS or did the format change?

atrox X viridis hybrids have been found in Presidio Co. Texas, and a couple atrox X molossus have been wild-caught in Culbertson Co. Tx.

There are quite a few reported and published cases of hybridization in rattlesnakes. C. atrox have been known to hybridize with C. scutulatus in several areas range wide. One of the best areas for this is the big bend region. A great majority of the "atrox" looking specimens throughout the Terlingua - Lajitas area are hybrids. Although they look like atrox, scale counts reveal intermediate counts, even having two pairs of the paired prefrontals diagnostic for scutulatus. There are other areas too where these species cross.

I know of several pictures of hybrid rattlesnakes (including atrox X scutulatus). Good ones are in Manny Rubio's book "Rattlesnake".

hybridize with C. scutulatus in several areas range wide.
"big bend region."
"Terlingua - Lajitas area"

Thanks alot for the info... I'm not familar with the localities that you mentioned though... What state/area are they in? Also could you be more detailed about scale counts? I was just wondering.... I would like to learn as much as possable excpecally regarding identication... well thanks agin

Terlingua and Lajitas are two small towns in the "Big Bend" region of west Texas. On a map, follow the Rio Grande SE from El Paso and you will see them.

There are several defining scale counts in these two species. Instead of regurgitating them here I suggest you look at Klauber's Rattlesnakes. He discusses in great detail the characters that define scutes and atrox. Hope this helps. Ask more if not... Cheers