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Hey guys,

I was wondering if anyone could help me out with a question I've been pondering during down (winter)time. It goes like this. Most mountain sides in Creosote bush desert will have their Chuckwallas. How did they get there? To go further into it, when habitat becomes unfavorable do they make a mass exodus over miles to a new more suitable habitat, or do they simply dwindle away? Also, even if there are no human interferences, wouldn't a population become heavily inbred? What about that? I am suggesting that Coconuts, er I mean Chuckwallas migrate, but don't know if there is any truth in this opinion. Has anyone heard of Chuck migration? If so what sparks it? Thanks for playing along with a curious mind.

regards,
-Phil

The same questions applies to island specific chuckwallas. As far as how they they got there I'm not sure what you mean by that question, but I would say God put them there. As far as the interbreeding. It is a known fact that lizards do interbreed from time to time, but if you've ever put two males in a cage during breeding season or even when it's not they will try and tear each other up. So the dominant male is usually mating with at least one or several females in his territory as well as the loser mating with females in his territory. This territorial instinct maintains some integrety of the race, as well as certian interbreeding can causes weak animal lineiage that may or may not survive. As far as migration, I think it's the other way, in horrible circumstances such as drought they dwindle down, but ususally a few make it through. These are all good questions to ponder not only in Chuckwallas but also in other species as well.........
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Phrynosoma.com

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signature file edited. [phw 11/14/04]

i have been wondering both of those same questions also, because i couldnt imagine chuckwallas crossing flats and valleys to find more suitable habitat.oh and thanks for watching out for me im well aware of the laws about state park wildlife i only plan on taking pictures in the valley. and maybe doing some herping near los vegas away from the state park.

to wonder about, as repto man said with ALL species.
Guess it all comes down to SURVIVAL, they go where they have to , when they have to , to get what they need to LIVE.

When they are forced to move, it may also help , as far as the Inbreeding issue. Expanding their habitat, would only allow them to come in contact with new blood wouldn't it ????

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PHEve / Eve

As far as your first question you are talking about millions of years of evolution. Climate just does not change of course overnight. I believe that many of the deserts where pine forest at one time so a mass exodus does not happen. If you are talking about a long drought period which causes food shortages no they do not migrate as a whole. They usually become very inactive and you might not see them for long periods and of course some die. These creatures are very adapted to this type of life and can survive long drought periods by remaining dormant.
Chucks are thought to migrate accross flats in small numbers to other prefered locales when they kicked out by dominant animals or the area is overpopulated(with chucks). They also start valid populations in some areas in sandy flats that are not typical chuck habitat in which case they burrow in cliff sides and in sides of dried riverbanks. There was an article out a few years ago by Jerry and Marty Feldner in one of the herp society journals from out west on chucks that inhabit areas that would not really be considered typical habitat for them. I have also seen this in several NV populations-not a rock bigger that a baseball in sight and there where populations of chucks inhabiting the area. It really was a shock to me as i have thought that they would only live in rock strewn areas. I think what triggers the migration would be over population of a said area.
The inbreeding thing is a touchy topic. Some think that it does not play a major role in reptiles as it does in mammals. A lot of populations of lizards must have a lot of inbreeding because of the way they live as you mentioned with the chucks. A good point are Cunningham Skinks in Australia. These guys inhabit small rock outcroppings maybe no bigger than 25 feet around with maybe the next closest one being 4-5 miles away. These little microhabitats in this vast expanse of sand harbor strong populations. The asdm was working on some of this. They have a good population of Ctenosaura hemilopha macrolopha on the grounds that was started from just a few animals back in the sixties. These ctenos along with their population of Sauromalus varius would be good groups to study about inbreeding on. I know they started to do the DNA work on the varius to see how closely the animals they have are related and if they are getting genetically more alike to see if there might be genetic depression that would effect the health of the animals. I gather that from conversations I have had with some of the people that work there is that in the past animals where bred at random without much effort into keeping seperate bloodlines. I believe the cteno study is only a thought at this time because of the work and money involved in the proccess.
A lot of good graduate work out there for academics. Unfortunately these type of studies are very poorly funded so it is not that attractive to professionals. Oh well. Tom

Very well said Tom ( Hows it going ??!!! )--- I am not very well educated on these matters so I will not chime in much-------------------- but Tom--- I have to know something!!!!! How long did it take you to type all that!!!!! My two fingers are sore just thinking about it!!

David in wet East Texas

"...in which case they burrow in cliff sides and in sides of dried riverbanks."

Dried riverbanks are only dry when there is no river present. What with all the rain we've had lately, and all the "rivers" created by flash flooding in desert areas, as well as the tendency for chuckwallas to float around like footballs, couldn't catastrophic weather be responsible for displacing populations? This may explain alot of things including genetic diversification.

For the most part I believe that when they burrow they have an instinct as to where and how deep. Although there is an occasional flash flood, if you look at the torrents of water, even a foot deep, there is a good likely hood they would not survive such an ordeal, but in the prbability this could happen, certianly if they survived there is a possibility for new blood lines, but there is also the likely hood the chuck or couple chucks or whatever ampount will never cross paths and may even end up in a dormant area as Tom pointed out where there are no other chucks...........
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Phrynosoma.com

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signature file edited. [phw 11/14/04]

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Hey everyone!

thanks for your opinions and input. Here's some background on the possession of my mind. lol. I was talking with my brother about Chucks one day and when we get together and talk herps, a question of interest is raised quite often. Thats where my question stemmed from. We postulated that Chuck populations can be seriously affected by collection of even a handful of adult females, but decided that there must be a way for life to continue for these hefty herps. So why are there three or four groups of mountains in about a 40 mile radius that all contain a similar looking strain of Chuckwalla? Its obviously been a long time since the mountains were one big chain together, so I assume that some movement is inevitable, and as Tom pointed out I guess they CAN live in an area not completely covered with large boulders. Thats awesome! I've never heard of anything like that. I also didn't even weigh the idea of natural disaster in....That would make sense also. My only question is about the remaining Chucks that don't move. Does nature "select" them? Oh well, another thing to ponder. Seriously, thanks for answering some of my questions. I feel knowledge enriched right now, heh. Thanks guys, and by all means keep the responses coming if you have 'em!

regards,
-Phil