# Hairless or Double Rex?



## Phantom (Apr 4, 2012)

So this came up as an interesting side topic in this thread: http://www.ratforum.com/showthread.php?57418-Shedding-Like-A-Cat

When I bought Molly I was told she was a double rex and both her parents were rex. I've never actually seen Molly's parents, but I pretty much believed what I was told at that time. 

However, seeing as her daughter, Mimi, is not exactly a rex rat I might be wrong. I might not be wrong though because Molly is not completely hairless and shows the obvious curly whiskers and some curly hair that grows and falls out whenever it pleases. She has hair on both her legs and her face.

I was just curious as to if she really is a double rex? Someone brought up the question on what a true hairless is then in the previous thread. Could anyone shed some light on her genetics?


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## LightningWolf (Jun 8, 2012)

She is hairless. Hairless rats are like hairless cats. they still have hair to an extent (just very fine). most hairless rats have whiskers, and small amounts of hair on their faces and limbs. Hairless is a recessive gene (hr/hr).

Double rex rats can vary from almost hairless (they have hair All over their body though) to looking like normal rex rats. they tend to shed and change their appearance all the time. It is 2 rex genes (Re/Re) reason it's called Double Rex (Rex is a co-dominant gene. so Re/Re = DR, Re/re = Rex, re/re = standard and re/hr = standard hr/hr = hairless)


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## Eden10 (Aug 11, 2012)

I always like this topic! I had been confused about it since the subject was brought up. Sorry to butt in your thread, but I just had a question...if you don't know your ratties parents, what are the easiest ways to tell a Hairless & DR apart? Again..hope you don't mind me asking a question in your thread, Phantom!


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## LightningWolf (Jun 8, 2012)

Basically, this is the difference

DR - hair on body (this is normally peach fuzz but it is All over the body). Hair sheds and regrows in different places (hence why they are called Patchwork rexes sometimes).

Hairless - Little hair on body (Hair should Only be on face, limbs, I believe even the lower part of the rump, and whiskers but this should be peace fuzz). hair does shed but does Not grow back in different places.

Hard to explain without pictures, and I dare Not open up another link. my internet really hates me so every time I open up 2 tabs it freezes, and it takes me having to restart my computer And reconnecting to the the internet like 5 times to get it to work again  Some days I swear technology takes us 2 steps back instead of forward. (we know what the issue is fortuantly, doesn't make it any better though).

Here, those of your with True DRs post pictures of them, those with True Hairless rats post pictures of them so there is a comparison (or if your confused we can help you with it I guess).


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## Phantom (Apr 4, 2012)

Eden10 said:


> I always like this topic! I had been confused about it since the subject was brought up. Sorry to butt in your thread, but I just had a question...if you don't know your ratties parents, what are the easiest ways to tell a Hairless & DR apart? Again..hope you don't mind me asking a question in your thread, Phantom!


Nope, it's all good. I made this topic so questions could be asked and answered about hairless rats. I figured it would help out with my confusion and the confusion of others in the future should they visit this forum. =P

LightningWolf- I was always told hairless had no hair at all, sometimes not even whiskers. Someone needs to write a standard guidebook to all the ratty genetics. Lol. It would help out owners, people who want to learn, and those who are interested in the medical field.


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## LightningWolf (Jun 8, 2012)

Phantom said:


> LightningWolf- I was always told hairless had no hair at all, sometimes not even whiskers. Someone needs to write a standard guidebook to all the ratty genetics. Lol. It would help out owners, people who want to learn, and those who are interested in the medical field.


People have actually done this, simply search for rat genetics and you can find a lot of websites. I would type up all the genetic codes, but to be honest, some stuff just has so many genetic codes (as in take Varigated rats. there have been reported to be around 5 or so Different genes that can cause it. Though all of them are Dominant though). Plus there are some genes Not found here in the US but only in places like the UK (take roans for example, while found in the US they are rare, but very common in the UK) or places like Australia. they have silk rats. I think it's basically a long haired/velveteen satin? not 100% sure. If I am right they also recently found a long hair gene over in Australia as well.

Anyone who wants to learn the genetic codes and what they mean are always welcome to PM me. I love talking about genetics, reason I like these types of discussions. Let me see if I can find some examples of Hairless vs DR.

Oh also, there is a difference between a Standard for a rat show, and what the gene actually causes. Double Rex isn't a recognized variety, and the hairless standards are very vague in my opinion. Then again, in most countries Hairless rats can not be shown at rat shows.


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## Eden10 (Aug 11, 2012)

Yeh I had been told also that Hairless rats shouldn't have ANY hair not even whiskers...yet once I did more research apparently light fuzz is acceptable & short/some whiskers are allowed.
I think like I believe I have mentioned before, the less hair the more valuable the rattie when it comes to Hairless rats.

Fester is my 100% certain Double Rex...

Him as a baby....








Going thru a 'molt'...








Blurry, but this is most recent his hair has grown back again...









& I now know that my other boy Herman is 100% Hairless despite sprouting a few whiskers...guess just some people have higher standards with their Hairless ratties & want them to have nothing, not even whiskers.


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