Showing posts with label rattlesnakes. Show all posts
Showing posts with label rattlesnakes. Show all posts

Friday, July 1, 2011

Suzio Report - Hands-Off Snakes at Dens

Howdy Herpers,

As some of you will remember, the last Suizo Report mentioned an alligator lizard with red banding on its back. At the time of discovery, one member or our party suggested that the red signified that this was a female that was gravid. This suggestion brought forth a flood of replies, not a one which whole-heartedly agreed with the diagnosis. I could, of course, cut and paste everything that other people said, but that would generate even more dialogue on a subject that is in severe need of scientific analyses. I'm of the opinion that none of us know for sure what is up with coloration in Elgaria kingii.

I will paraphrase what was said by everybody, and be finished with the subject. If anybody has seen anything in lit land, please let me know. Otherwise, we all, myself included, are just speculating based on our own experience.

Some are in the camp that states that yes, they change color in May and June. But it appears to be more with males than females. These are folk who are only talking about wild populations. I am in this camp, but freely admit that I don't know enough to be sure.

Also popular with other field folk is that their color is only a relic of their substrates. These people would agree with what comes next. 

Others, mainly keepers of the California species, state that they flat out never change color. Several have had females lay eggs, without any color change. In other words, whatever color they were when collected is the color they stay. Males or females, no change.

I think it was a great discussion, and thanks to all who participated. What I have walked away with from this discussion is that many of us think this is a very cool species of lizard that deserves more attention. I know I that will certainly be more focused on them in the years ahead, and know several of you will be doing the same. Cool! And thanks everybody...........

Also, for the benefit of those of us who thought the first cerberus found on 3 May 2011 was both a female and pregnant, the info that I received from the cerberus pros would indicate that she was indeed a she. As for being pregnant, some thought it possible, but could not say for sure from the image provided. We can probably safely say that she was either pregnant, or about to defecate.

Enough history. And on to more history!

I am slowly but surely scanning some of the 35mm slides in my collection. The very best moments of my life occurred back in the day when that was the best way to take photographs. In particular, 1990 through 2000 was the time period when I scored numbers that easily triple the snake numbers that I see today. While some of this phenomena can be attributed to being younger, lighter, stronger, faster and more motivated, there is more involved than that. The early-to-mid 1990s brought us consistent precipitation in both the winter and the summer. Whereas the average rainfall in this century has been ~9 inches, it was ~12 inches in the 1990s.

Also, as mentioned in an earlier missive, I was inclined in the early part of Y2K to get grabby at atrox dens. I remain convinced that this worked wonders in declining visuals at the dens themselves. Another reason for lower snake counts might have something to do with radio-tracking individuals. The time it takes to do datasheets alone could be impacting the counts. But the bottom line is that the 1990s were my glory years, and I'm pleased to share with some images part of what I learned.

All captions are placed above the images.

Pic 1: Ron's Den, 19 March 1995. This photo was taken the day we found the den. The big snake that is plied on top of the others even earned a name. Said name was Tyson, for he ruled this den in a most aggressive fashion. I learned much from watching this den in a hands off fashion. I will only go in depth on two of the phenomena I learned at this den for now. They were (and still are--this den is still thriving, I'm just afraid to go there now): 1.  Desert Tortoises are overwintering with the snakes here, and 2. So are pack rats. Let's go to the next picture, where the importance of the pack rat to the hibernaculum will be discussed.
 

Pic 2: Atrox with food bolus, just outside of a den we call "Dan's Den," which is located at Saguaro National Park East. This photo was taken in February of 1999. Dan's den was first discovered by Dan Bell, and I was there for the first time in January of 1993. Every winter from 1993 until this photo was taken (1999), the place was packed with both snakes and pack rat debris. Take a look at the food bolus in this snake. Does it look like it could be a pack rat? The den was empty the next fall, and had zero pack rat debris packed inside it. I have not seen an atrox in or at this den since the spring of 1999. I do believe this boy ate himself out of house and home! (No--the pack rats are not safe with their playmates during the colder winter months).
 

Pic 3: Image taken 19 March, 1999. This is from AD1 on our study plot. The den was discovered just one month prior to this image. It was after dark when I approached the pair, and saw their tails intertwined. They were in a peaceful posture, but as soon as the flash went off the snake "woofed" at me, and is viewed rising into a defensive posture. Go on to Pic 4.

Pic 4: There are two things evident in this image. The first is that the female is escaping into the crevice ahead of the male. The male is holding his ground, and did so until the female was all the way. He then followed her. This form of "mate defense" was evident at many of the hands off dens I had. The boys are protecting the girls! The second thing that is evident is that the the girl is the very first female atrox we ever put a transmitter in. Good old CA1, "Ruth." We knew her two years before we knew her!

Pic 5: Suizo Mountains AD1, 6 March 2001: This image was taken ten days before we captured CA1 to formally begin our study. Let's just bop on to Pic 6: 


Pic 6: AD1, 9 March 2001. 7 days before we snagged CA1. I do believe that our second subject, CA2 "Dianna" is the snake with the rattle showing on the left. Be we did not actually catch her until 22 March. 

Ever since we started this study, the snakes have stopped basking on the apron en masse like this. To be sure, most returned, most showed fidelity to the site. But when they basked, they moved away from the den apron. I'm not damning telemetry or our study with these words. I'm just saying that before you mess with any animal at a den site, know what you will lose as a result! 

On a positive note, we are keeping our hands off this den now. It is starting to come back to what it used to be.

Pic 7: Pikachu Den, Hill 97, 20 November 1999. Once again, we did science at this den. Grab fest, PIT tag, release, and it was never the same. But once again, we are keeping our hands off, and it is coming back. If you look carefully behind the snakes, you will see there is a tortoise in the hole with them. 

OK. I'm pleased to report that last spring, we found a few new atrox dens that will be monitored with hands off fashion for as long as we are able to do it. I still have yet to find anything as good as Ron's Den, or Pikachu, but I'll keep trying.

Best to all, roger

Saturday, March 19, 2011

Signs of Spring


Spring is approaching the Northern Hemisphere and the media is carrying stories of reptiles emerging from hibernation CBS 8 News is covering Opp, Alabama where city officials are promoting the Rattlesnake Rodeo that is held April 1 and 2, and report the stadium will be lined with vendors and that day passes are $15. KOAV TV in Tucson is reporting that the Northwest Fire District is warning residents to be on alert for dangerous rattlesnakes and offer tips to avoid an unpleasant encounter, like: watch your step, use a flashlight at night, keep to walkways and areas clear of brush, and wear closed-toed shoes. And the Amarillo Globe-News has a blog carrying a story about Jay Weddle and his experiences with rattlesnakes, including inventing a tube that holds open the nostrils on a horse if it has been bitten by a Crotalus.

Last week Roger Repp gave me a day tour of several southern Arizona reptile hibernacula and there is no doubt spring is approaching. Despite a week of mostly 80° F+ temperatures many reptiles are still staying close to their crevices, but they are near the openings, see below.