Reptile & Amphibian Forums

I understand that there is different scaling on the heads of these two species that one can use to make a positive identification. I've searched the internet for pictures, but am unable to see a side by side comparisson. Could someone please post the two head pics to show me the difference.
One night I was down on Vuture Mine Rd. a couple years ago durring one of my trips to AZ. and stopped behind a car that was stopped on the side of the road. It was a rattlesnake he was taking off the road and he said he thought it was a Mojave. When I asked how he could tell and rather than admit his ignorance,he just never answered. It was clear he couldn't tell the difference either or couldn't be bothered wasting his breath on an amature like me. If someone could PLEASE show me how to identify a Mojave it would be greatly appreciated. Thanks. Colin

I dont think you want to get close enough to read head scales, unless its DOR its not worth the risk. Atrox and Scutes look similiar but they are different enough to go by color, location, and tail ring width. They are both common snakes along the CA/AZ border.
Heres some shots of both.
Cheers
Brett

Thank you for the pictures Brett. Lets say the greenish color is lacking in the Mojave as I've heard is sometimes the case in some locales, will the wider tail bands in the Mojave be a pretty fail safe way in differenciating them?

No worries, well "typically" as you can see from the picture the scutes tail rings are different, now you could come across one (atrox/scute)that does not conform to the rules and the last resort would be to start looking at head scalation. I personally am not that precise, they are both common snakes in my part of the world and not of intense interest to me.
I would use color, tail band width, and location to help with the ID, there will always be oddballs so take lots of pics. Ive also noticed that Mojaves seem to have a smaller head.
Cheers
Brett

that would be one of the scute/ atrox hybrids you pictured w/ your second reply. Wierd to think something like that could be a result of two breeding, it looks nothing like either of them, Lol roots

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FREEDOM PEACE UNITY ONE LOVE

I figured I should post a series of them LOL

B

Atrox and Scutes look similiar but they are different enough to go by color, location, and tail ring width.

Further east, scutes aren't quite as green and the difference in tail band width isn't as pronounced. In general, the outlining on the blotches is bolder in a scut and the black tail banding is narrower. You just have to "learn" to recognize them.

Here is a snake from that was born in captivity to a snake from the Hueco Mts. I found the gravid mother and couldn't be sure what she was. She looked like an atrox/viridis hybrid (all three occur in the area). She gave birth about a week later and all the babies looked like scuts?

Here is one of the babies that grew up from this litter. It is a scut....I guess?

Here's an atrox head closeup.

The lack of larger scales (other than the supraoculars) are what you see in atrox. Scuts have larger scales.
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Chris Harrison
Central Texas

I'm usually pretty good at making the ID, however, on that road in Brewster county I was hunting a month or two ago I was seeing both, that were clearly easy to ID, after a good while I started seeing intermediates that no way I could ID from looking at them on the road.

I'm not great at putting the "why's" into words, but I'm sure you'll agree that sometimes you'll see those animals that defy easy ID as to atrox/scut, and they may well be hybrids with varying amounts of parantage from either species.

Forky

if you are saying that identifying scutes from atrox in some places and that particular area of west Texas.........I to have had that problem of positively identification. I mean on areas of RR and even on 118. It is not until sometime later that I can ( with even help sometimes ) know that I have seen a true scute. I find it more problematic on young ones or juveniles than adults though.
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I may be old , cantankerous, crabby, and cynical, but......

I was further north at a higher elevation, but yes, the damn things are breeding together, I'm sure of it! haha (at least that's my story and I'm sticking to it).

Forky

They interbreed in many localities. One of the things you wiil usually notice in these areas is overgrazing. If I remember the story right (please help me out here if ya read this Hugh) HKM was doing research in the Christmas/Study Butte/RR area and thought many of the rattlesnakes were showing signs of being intermediate. A number were sent to whatever university is in El Paso and they found that the snakes that appeared to be scute were indded pure scute but there were NO pure atrox. They all had scute influence.
Everywhere I have found hyrids I see the same thing. The snakes basically have an atrox color and pattern, it's just in the head shape and scalation and ventral counts that one sees scute. THe head shape and scalation comes in many degrees. Some have a complete scute head on an atrox body, others look to have been bred back into atrox again diluting the scute characteristics. BPO and I saw some real oddballs near Ft. Davis this year. I am really kicking myself for not getting some pics, don't know where my brain was. We were running late for meeting the ole Buzzard at Boy Scout to look for coppers so we just tossed them off road and skeedaddled.

Rich

interesting obs on the overgrazing part, it would be interesting to see if they are mixing out here, if they do in fact overlap. I personally have not found them in the same areas in the Mojave Desert, though they must come in contact? I find atrox out here but have to go farther N, NW, or NE to see scutes. These areas are normally 2-3 thousand feet higher than where I am which is about sea level +-200'. The atrox I find here are normally at 1500' or higher and only 30 miles to the east, placing them well within CA. No real eye openers here just some of my own notes.
Cheers
B

You're obviously not a sailor or an airman, as plus or minus 200 feet is a big deal in those fields
In regard to atrox and scutulatus, this is the best picture I can offer:

C.atrox exist in that salty environment, along with Nerodia!
After having a good view of the Colorado river, in the area where you live, it's no surprise that the atrox can do it, and the scutulatus are screwed. The historical ranges are historical! I imagine that in the past, it was simply a notable river, but now, it's a human lifeline.
Shane
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Shane's Herp Lifelist
http://www.geocities.com/shane77@sbcglobal.net/my_page.html

20,000 miles of bluewater under my keel, and more than one solo voyage around Cuba, heck I can even take paying passengers out for a sail but its hard to do when you live in the desert LOL. So you have found the marshland atrox? I heard of the beasts but never see one around the river.

Ciao
B

...dunno what that has to do w/ squat...but I always liked the expression...zzzz

pretty amazing atrox spanning habs from gulf coast marshes to the calif desert...& mixn w/ viridis & scoots along the way...

good thing weve got getulus n' indigos in between us or those nastys would probably take over the friggn world...

spkn of nasty....whos man enuff to do this.....not me I took the pic!

Those things are gross, about the only thing that will make me cry like a baby. Now this is what you ought to be holding on to!

...yes indeedy...fine studded monsters they are

Whooaa...whats this...

Regal ringneck snake (Diadophis regalis); Locality Voucher

Location: Spur Cross Ranch Conservation Area, Maricopa County Az.

Coords/elev: 33,53',30" x 111,57', 0" @ 2320' (707 m).

Date: 11.2.2005 @ 1600 hrs & ~ 84* F (28.88C).

Observer: John Gunn

Comments: 2nd specimen observed-reported on Spur Cross in 4 years. These appear to be low elevational records. Apparently this spps can persist in Upland Sonoran Desert. Others have been seen higher on the forest to the North.

Recently fed female, seems to be in good condition; fairly stout ~ 18-20" (~ 48 cm) ~ 20 grm w/ full neck ring. Lying imobile, elongated in the center of a dirt road in the shade. Fortunately, we centered it w/ the vehicle @ the Cottonwood-wash / Spur-X Trail intersection.

Immediate area; dry mesquite bosque arroyo system, with Cave Creek ~ 500 m to the west. Saguaro-bursage ironwood community on s exposures, & shrubby buckwheat-ratney-jojoba community on the n slopes. Fairly rocky undulating area with foothills nearby.
Serpent was oriented towards the east.
It really held on to its perceived stationary crypsis until actually touched. Tail coiling was deployed when touched. Significant musk discharge when picked up, no attempt to bite nor drooling was noted.
First defecation had small smooth squamate scales clearly visible.
Jpgs of the serpent, site, & a map jpg should be bundled w/ this file.

whatcha got there eh? A ringer from the creek, amazing, and i thought my tiger was interesting. Glad to hear that "official" did not squash the serpent, Im sure you would have had to draw down on him if he did LMAO. So, I tried to call you today, I'll try again manana.
Ciaoski
B

I wouldn't do that, I've been nailed by one of those before.... it wasn't pretty.

However, I have seen a man bare hand them before, Bill is his name. The trick is not to restrain it, just let it crawl right onto your hand. Then they don't bite. Yea right, I'll take his word for it. haha

Forky

So those things really do bite? What is it like? I am terrified whenever I uncover one of those. I would rather handle a rattlesnake.

caught a few of those buggers in the florida keys a year ago....quite frightening lil things. never saw a centipede that size except for at a herp show, so finding them in the wild was quite a thrill. catching them was a bit rough! youd never see me freehand one of those things though.
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-Mike Martin
North Carolina

from near the Huecos that I am sure is a scute X viridis. It's just a pretty scute as far as he is concerned. The snake's head looks viridis, it is completely lacking enlarged infra-supraoculars and the lateral blotching alternates with the primaries rather than matching up like all the other scutes from the region. When I get a little more time I'll post an atrox/molossus hybrid he has from teh same area.

Rich

That looks more like an atrox to me. Although I am basing it off of the head. The body pattern and coloration resembles scut more. I can certainly see why you are having issues with identifying it. My vote is atrox (at least from the pics).

np
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Shane's Herp Lifelist
http://www.geocities.com/shane77@sbcglobal.net/my_page.html

what i look for-atrox has slightly bigger head;mojaves have a smaller head with proportionately larger eyes(again,slightly).....black tail rings are as wide as the white spaces between them on atrox;on 'scutes' they are narrower than the white spaces....yeah,some mojaves are 'greenish',but tons i've seen are not extremely so....according to conant/collins,atrox have the line behind the eye ending at the jawline/rear of the mouth;on the mojave,the rear eye stripe extends/continues beyond the jaw line....and the thing about mojaves having slightly larger head scales?embarrased to say it,but i never noticed that(that would explain the taxonomic species name,'scutulatus').

n/p