Extreme Variation in Captive Population

[Lena]

Hello everyone!

So I've always wondered, and I'm sure it's been discussed before, about the extreme variation you see in the captive bearded dragon population. And I don't just mean color, I mean things that weren't purposely bred for.

Facial shape is probably the most apparent example. Take a look around the internet at some pictures, it won't take you long to see what I mean! Some have extremely short, pug-like snouts, others have very long, slender faces, and everything in between. Pattern (Particularly on the back and side of the face), eye size and shape, eye color, and build are all other physical traits I've noticed have great variation. Of course, variation is natural for any single species, but in my opinion some of the variation is too extreme!

Take a look at the facial shapes of these beardeds that I found on google images...

I imagine that it's due to the fact that none of the beardeds in the pet trade are purely P. Vitticeps. In fact, I don't think it'd be unreasonable to assume that they're a mix of 2 or 3 different species, perhaps more! Also - Do you think nutrition has any impact?

Let me know what you guys think!

 

[Pravius]

My personal opinion about this is that because of the tight exporting laws of Australia we as breeders of these animals have a very very limited gene pool to work with then breeding. I think some of the variations could be multiple species intertwining but I also think it has alot to do with selective breeding and generation and generation of not really knowing lineage of these animals, which inevitably has caused various mutations and morphs genetically which can do things like change head shape and overall "build" of the animals.

 

[vickson420]

I agree with Pravius on this however some of the head shape can be attributed to the mixing of the vitticep with the GG morph as they had a very different head structure then your run of the mill vitticeps.Alot of it is going to be attributed to line breeding for genetics thus creating significant changes in head shape and size.For example I have noticed that a large majority of hypo/pastels tend to have a much sleeker longer head shape while alot of the orange/peach and red morphs have that stubby feature.Again I am not saying this is automatic its just what I have onserved and that is based on limited gene pool and selective breeding.

 

[Lena]

I agree with Pravius on this however some of the head shape can be attributed to the mixing of the vitticep with the GG morph as they had a very different head structure then your run of the mill vitticeps.Alot of it is going to be attributed to line breeding for genetics thus creating significant changes in head shape and size.For example I have noticed that a large majority of hypo/pastels tend to have a much sleeker longer head shape while alot of the orange/peach and red morphs have that stubby feature.Again I am not saying this is automatic its just what I have onserved and that is based on limited gene pool and selective breeding.

I can see how selective breeding can lend a great deal to this facial variation.

So perhaps the original breeding stock used to generate the orange happened to be predisposed or carried the predisposition for the short snout, and the same for the longer-snouted hypo/pastels?

Interesting.

So what I'm gathering is that you attribute it more to selective breeding and limited gene pools, not so much to hybridization? :|

 

[vickson420]

Both selective breeding and limited gene pool did play a big part IMO but you are correct I do not believe it was hybridization.The beardie's here in the US are very limited to the vitticeps as we dont have a large supply of their counterparts and definately not enough to cause hybridization in this manner.To the best of my knowledge the only types that have been crossed here in the US are the vitticeps and the Rankins however that was largely to expand the Rankins population not the other way around thus the reason why most US Rankins are at least part vitticeps somewhere down the line brining forth the US line which many call Drankins...lol.

 

[Pravius]

Well looking back when Dragons first started trading there really was not much to choose from in the way of genetics. It really depends on what you are looking at though. Like for instance the Colors of dragons can be found in the Wild type dragons it just depends on which region you are finding them in as it seems that evolution has played it's hand in helping these guys blend with the colors of their environments, I read somewhere that in some areas they are close to the color of the sand.

Australia has had some really tight exporting laws for some time now (I think the 70's) so the majority of stock found in the world is either working from the same or very similar gene pools or has been smuggled. Smuggling does happen with these animals. That's why it is important (this is my personal belief) to always question breeders on their lines. I work with breeders who tend to go back to the wild type dragons and do not continue to inbreed.... the way I see it selective breeding and inbreeding are two different things although many say it is the same. When you are doing it to improve the vigor and overall health of the species by taking the top picks from each clutch I think there is some justification in that. Some people do it just to see how much money can be made by creating or trying to come up with the next morph and that's where I personally cross the line and think it's bad.

Anyway that's a whole different subject. To get back on point though I think there are alot of variables one being the selective breeding with the limited gene pool we have in the US and the other breeding different types of dragons within the same species from different regions, backgrounds, ect.

 

[Lena]

Alright, alright. All very interesting points.

Here's my next question..

What leads you to believe that the original stock brought over from Australia was exclusively P. Vitticeps? Do you think people were really that exclusive back then? I kind of imagine it being more of a grabbing whatever specimens you can get, thus the hybridization occuring.

In fact... Now that I look at the localities of different species in australia, it seems strange that P. Vitticeps is the species that ended up coming to the U.S... Though they are seemingly the most prolific, why wouldn't a species closer to the coast (Closer to shipping locations) be more common?

Take a look:
http://users.erols.com/ziring/dragon-species.html

 

[vickson420]

Well the Vitticeps was generally considered the "prettier" of the species which is why the majority of the stock exported out was the vitticeps.They are generally the higher color variation,tamability and also the most docile of the species.The barbata was exported for its size as well but most of that was in an attempt to cross breed to create a bigger colorful dragon now known as the German Giant which here in the US was quickly diluted back into the vitticeps so truthfully no true GG are available here.You can find decendants of the GG however its way back in the line.The chances of actually getting a hold of a "pure" GG are slim.Most that have them would NEVER give them up and those that do charge a pretty penny.Bottom line is I am certain that somewhere someone has a few beardies outside the vitticeps but as I said no where near enough to dilute the breed and cause these variations besides most that do have them would be more interested in acquiring another of the line to breed pure because financially speaking that would be where the $$$$ would be.

 

[Pravius]

Well the Vitticeps was generally considered the "prettier" of the species which is why the majority of the stock exported out was the vitticeps.They are generally the higher color variation,tamability and also the most docile of the species.The barbata was exported for its size as well but most of that was in an attempt to cross breed to create a bigger colorful dragon now known as the German Giant which here in the US was quickly diluted back into the vitticeps so truthfully no true GG are available here.You can find decendants of the GG however its way back in the line.The chances of actually getting a hold of a "pure" GG are slim.Most that have them would NEVER give them up and those that do charge a pretty penny.Bottom line is I am certain that somewhere someone has a few beardies outside the vitticeps but as I said no where near enough to dilute the breed and cause these variations besides most that do have them would be more interested in acquiring another of the line to breed pure because financially speaking that would be where the $$$$ would be.

Concur also I am not sure if any studies have been conducted with hybridization. I am not sure if one variation would even breed with another... that I am not too familiar with. I know Vitticeps have a very interesting social behavior and not sure if any of the other species really display that type of behavior (Arm Waving, Head Bobbing, ect.)

 

[vickson420]

Concur also I am not sure if any studies have been conducted with hybridization. I am not sure if one variation would even breed with another... that I am not too familiar with. I know Vitticeps have a very interesting social behavior and not sure if any of the other species really display that type of behavior (Arm Waving, Head Bobbing, ect.)

Honestly I dont know of any studies either but I do no that any of the pogona species can technically interbreed however IF they had been interbred you can be very certain it would be labeled during sale because again that would = $$$$.
Also just to to clarify to those reading when I refer to types of beardies I am not referring to morphs.I am referring to the actual Pogona line which consists of:
P.Vitticeps-Central
P. barbata
P. henrylawsoni/Rankin's
P. minima - Western
P. minor - Dwarf
P. mitchelli - Northwest Bearded
P. nullarbor - Nullarbor
P. microlepitoda - inland

 

[Lena]

Well, I am suggesting that the hybridization occurred early on before it would be profitable to advertise such inbreeding.

They are all extremely close genetically speaking and it is known that P. vitticeps and P. henrylawsoni can produce fertile offspring when bred together.

 

[Pravius]

This may be a good idea of why you only see the more popular species in the captive population

http://www.environment.gov.au/coasts/publications/somer/images/som-fi74.gif

Looks like most of the shipping ports are in the eastern, North Eastern, and Southeastern Part of Australia.. not too many in the west from what that map shows.

 

[Lena]

Interesting! But this leads me to wonder why P. minor isn't more common?

 

[vickson420]

Well, I am suggesting that the hybridization occurred early on before it would be profitable to advertise such inbreeding.

They are all extremely close genetically speaking and it is known that P. vitticeps and P. henrylawsoni can produce fertile offspring when bred together.

Hmmm I do see your point however I am not sure why it would be done if not for financial gain.Its not as easy as one thinks even within a species to interbreed.It would have had to been a concerted effort.While I am sure it can and does happen naturally in the wild I still dont think it would be enough to make the changes we are referring to today.I think more likely its along the lines of a locational genetic influence just as it is with color.A beardie from one region may have developed a slight change to cope with its immediatelt location.I think that is why I have connected alot of the color morphs to facial variation,etc.Truthfully I guess anything is really possible and I dont know we will ever really know as I dont know how that data could ever be succesfully collected.

 

[Pravius]

Not sure that is pretty interesting to think about... one thing I did read on that site that you linked was it specifies that, "This species is not available in the pet trade", maybe there is a law in the US or some sort of international law prohibiting the sale of these. I may be stretching it, but who knows really.