Selective Breeding for Size; Health Effects?
Posted: Thu Jan 14, 2016 3:03 pm
I was trying to determine whether this belonged in advanced discussion or general discussion, but I suppose here would be more appropriate for more in depth discussion from breeders.
Anyway, the topic I want to discuss is selective breeding skinks to either be very small or completely massive compared to the normal counterparts of their species/subspecies.
I'm going to start with selective breeding for larger skinks. While I do not know too much about these cases, I have heard that there are "giant" leopard geckos and "giant" bearded dragons, so this concept has been explored in the hobby before. So let's I took two of the largest skinks I can find and breed them. I would then breed the largest offspring with either another very large relative or with new blood if possible. This brings along with it several concerns about health. If I simply bred for girth, I could eventually end up with a skink that has very awkward proportions and difficulty moving in a normal manner. This line of thinking would then bring me to selecting individuals that display largeness in length and that are proportioned correctly so to basically have a scaled up "model" of a normal sized skink. If we use that kind of selectiveness for breeding larger blue tongues, what kind of potential health problems might be seen in the future? Is there a limit to how big the skink could be bred for without health problems? If you look at Varanus sp. there is a vast difference of sizes including island gigantism. If such a thing over millions of years has happened would it be safe to do so in an artificial environment and significantly increased rates?
Now, tackling breeding for smaller sizes. As with breeding for larger size, let's assume that we breed for skinks that have shorter and shorter length while keeping anatomical proportions. This is where I think it gets tricky. How do we know if a small size is from either malnutrition (assuming wc, or unknown history) or just genetic? Would there be a point where they would start developing health problems?
Anyway, the topic I want to discuss is selective breeding skinks to either be very small or completely massive compared to the normal counterparts of their species/subspecies.
I'm going to start with selective breeding for larger skinks. While I do not know too much about these cases, I have heard that there are "giant" leopard geckos and "giant" bearded dragons, so this concept has been explored in the hobby before. So let's I took two of the largest skinks I can find and breed them. I would then breed the largest offspring with either another very large relative or with new blood if possible. This brings along with it several concerns about health. If I simply bred for girth, I could eventually end up with a skink that has very awkward proportions and difficulty moving in a normal manner. This line of thinking would then bring me to selecting individuals that display largeness in length and that are proportioned correctly so to basically have a scaled up "model" of a normal sized skink. If we use that kind of selectiveness for breeding larger blue tongues, what kind of potential health problems might be seen in the future? Is there a limit to how big the skink could be bred for without health problems? If you look at Varanus sp. there is a vast difference of sizes including island gigantism. If such a thing over millions of years has happened would it be safe to do so in an artificial environment and significantly increased rates?
Now, tackling breeding for smaller sizes. As with breeding for larger size, let's assume that we breed for skinks that have shorter and shorter length while keeping anatomical proportions. This is where I think it gets tricky. How do we know if a small size is from either malnutrition (assuming wc, or unknown history) or just genetic? Would there be a point where they would start developing health problems?