Breeding siblings together?

But considering the original question was one generation think were all good lol.


Oh yeah, definitely. :+1:

I missed out on the original question and jumped in when people started saying inbreeding was a good thing


I don’t think anyone in this conversation is saying inbreeding in the constant generations as some have posted about is a good thing.

The subject started on asking if sibling to sibling is ok to produce viable offspring.
I think we all can agree that inbreeding the same line over and over for countless years without adding any new blood is not a good thing.
Inbreeding sibling to sibling has no health issues unless you’re talking about a specific morph, ex. Black Pastel.
As @osbornereptiles mentioned and I think most in the hobby know this, most if not all the recessives we have in the hobby come from inbreeding.

To take it to the level that we have to discuss inbreeding over and over in the same family line is a little much. I think everyone with common sense knows that eventually you will produce deformed hatchlings doing that.

And I’m not trying to attack you personally Hilary, just using that quote to explain a side.


I definitely get that, there were just several comments about inbreeding leading to a “genetically stronger animal” when we know that isn’t the case. A pretty animal? Sure. A healthier/stronger animal? No

Obviously the conversation spiraled beyond just breeding siblings, which I think most people are fine with

I hope so, my faith in the scientific literacy of the average person is little shaken this year, so I’m not trying to beat a dead horse. I just genuinely don’t know what people do and don’t know


So if you inbreed one generation two siblings from a line with say a stronger immune system would they not produce offspring that have stronger immune system?

1 Like

4 posts were merged into an existing topic: Inbreeding in feeder rodents

Actually the immune system is one of the most vulnerable systems when it comes to inbreeding because it requires diversity of MHC genes.

Inbreeding and effects on the Immune System
How does Inbreeding effect the immune systems of animals
Inbreeding and the immune system: unintended consequences

However I totally get what you’re saying and acknowledge there may be traits that you want to keep in the collection beyond just the morph (maybe clutch size or something like that) and inbreeding may be the easiest way to keep that trait in your collection.

I don’t know anything about ASFS or their breeding so hopefully someone can jump in and answer this one


A post was merged into an existing topic: Inbreeding in feeder rodents

I was just picking a random trait! Guess I picked the wrong one lol. I never claim to be a geneticist so I always appreciate yours and Travis’s input. Always trying to learn!


Thanks very excited about this one, I’ve seen this pastel enchi combo paired with other morphs and loved the results!

1 Like

When I get to the point where I am raising BP’S. I really won’t feel comfortable with breeding siblings together out of a clutch or breeding daughter to sire or son to mother.
I was always told this was not a good thing. No matter what kind of animal it is. So I myself would rather sell the babies from the clutch or trade with someone to get another BP that is not related to keep my project going.
I guess I am old school. I never did that with horses when I raised them. Some people would. Everyone has there own way of doing things. I just want my collection without inbred animals in it.

Is this going to be impossible to do and get the results that I want? I do not know. That is the question I will ask you guys. Will it be impossible?


So long as you don’t discover a new gene, it won’t be. Only thing it could do is cost more in the long run. Not the worst thing given it will provide the healthiest stock for breeding.


Well I didn’t think about discovering a new gene. That would be a hope i do, but hope I don’t. Would not know what to do with it. LOL, more questions to come on that.
I know I probably won’t ever make a lot of money raising BP’s. When I raised Horses I loved the babies. I’m getting older and can’t deal with the big horses and breaking them to ride anymore.
I discovered ball pythons, all the beautiful colored morphs. I found something that I could enjoy in my retirement years and can handle now that I am older. My brother bought me a Piebald BP for Christmas in 2019. 4 year old.
He is beautiful and very docile. I am doing all the research I can now so I can do the best I can when I start buying more BP’s and breeding them.
Not to make a bunch of money.
Just for the love of the animals. If I make some money, thats ok too.


That’s so awesome!!! What a nice retirement hobby!!!


You are making my point.

Yes, you may have a snake that dens in the same location. Ecological studies have shown us that by and large it is the females that establish den sites. So we have a denned female that you observe every year, is she breeding with the exact same male every year? And is that male her brother/father/son? No and no. The males of the species tend to be more travel prone because they move around a lot trying to find females to breed. So she is going to be seeing a new male each year.

Next question - Are all of the babies she produced every year also denning with her? No, because the carrying capacity of the area is really only sufficient to support a single adult animal. The babies may hang around for a part of the season because their prey specificity is not in competition with the female, but eventually they will have to move on because they cannot compete with her and each other. So they begin to travel outward to find their own territory/range/den.

Next question - What are the odds that the territory immediately next door is going to be openly available and not already inhabited by another adult, established animal? Probably pretty low. So the babies have to keep on moving until they find an open territory. Odds are that open territory is going to be rather distal from the mother’s denning site.

Even if the most immediately proximal territory is available however, revisit what I mentioned above about males being roamers. Males are not likely to be establishing any set den site, instead, they will essentially behave as a vagabond; traveling along looking for the best opportunity to eat and (once old enough) mate where and when they can but never actually settling down. By the time the males reach sexual maturity (1-2 seasons) they will have traveled some distance from their mother’s den site and (because snakes are not social pack animals) they will also be distanced from their siblings. You also have to account for the fact that the males reach sexual maturity faster than the females. So even if the male is proximal to one of his sisters when he reachs sexual maturity, he still will not be able to breed with her. And by the time she has reached sexual maturity and found a den site of her own, the male will have moved along in his own travels.

Add clutch attrition into the equation. High probability that only 1-2 animals in the clutch will even make it to sexual maturity

Can you honestly say that, even under this simplified accounting, when you combine all of these factors it is realistic that inbreeding is occurring at high levels in nature?

Yes, there are many thousands of unrelated animals mating together in a small area. As a related analogy - if I stuck you and your sister together in a pitch black room with 1998 other strangers for a blind dance contest, what are the odds you would accidentally happen to pair up with her?

So again, low chance of inbreeding

I work with Black Gaps so I know all the fun of locality alterna. But, you are conflating the captive population with no account of the ecological range. How much area makes up the entire range of the Black Gap locale? How many animals are inside of that locale? How likely is it that any two given random animals from within that locale are directly related to one another?

Yes, to maintain the specific traits the line was selectively bred to have, you cannot outcross because of the potential to lose those traits. However, that does not mean those lines are perfectly fit and do not have issues unrelated to the specific traits they were bred for.


With all due respect Dr Wyman this analogy has been edited so that it no longer is in a little poor taste.

Fixed it for you.

Well if it was referring to my sister I wouldn’t be very happy with the analogy. Was not trying to offend you in any way.

1 Like

Was not offended. Originally I was trying to stick to the whole inbreeding topic so… you know… Brother/sister pairing is closer than brother + sister dancing.

Was not trying for poor taste but I was worried it might have skated too close to the edge for some people (which was why I put the PG-13 caveat in there)

Mr. Wyman
I know there are incubation issues sometimes and it causes deformities in BP’s. I have seen videos of hatchling’s having what they call shark mouth, have no eyes and kinking down their back. It is really ashame that these poor babies have to be like this. Is this only incubation issue’s?
Can some of this be inbreeding issue’s?