Reptile & Amphibian Forums

Hello all,

I have a clutch of seven gray bands that all look plump and healthy. The only exception is that 1/7 has a slight kink near the tip of its tail.

I am lookig for information on this topic so I can try to avoid it in the future. BTW, The one with the kink happens to be the best looking snake as far as color and pattern out of the clutch.

What causes a snake to developed with a deformity like this?

Thank you,
Tom

The snake pictured is a 1999 male west langtry - not the one with the kinked tail - I will post some pictures of the hatchlings soon!

Kinks can be caused bya couple of different things. One is incubation temps. If the temps got too high or spiked often this could affect embryonic development. Eggs can usually tolerate temps into the high 80's briefly but high 80's and up for extended periods of time can be harmful. The other cause is genetic. Are your breeder animals related ? The best thing to do is because you dont know if its genetic or temp related is to not use that animal in any breeding project or sell it to someone who may breed it. A kink can be like a recessive mutation,if its genetic, so it can make het for Kinks etc.... Some people actually put these type of animals down so as to insure they dont get into breeding populations. Thats a bit extreme just make sure if you keep it or you sell it its not used as a breeder.

Keith

No, the animals are not related. The Temps in the incubator, as far as I know, were a constant 82°F.

The snake with the kink will either remain in my collection, go to a friend, or go to a teacher friend's science classroom and will not be bred.

TA

I highly doubt that kinks are genetic and the result of inbreeding. Inbreeding usually results in the depression of the fitness of the animal, not gross morphological changes.

Another cause of kinks may be nutritional deficiencies in your breeders, especially the female. Calcium is probably the most likely culprit though it could also be some other mineral. Mosts snakes do not require any supplementation but I often wonder if we are not pushing the extreme every year with our breeders especially since cb females seem to lay larger clutches of eggs more often than their wild counterparts.

I agree though that temperature during incubation is the most likely cause.
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Rick Staub
R&R Reptiles

Im going to have to disagree with you on this Rick. Anytime you lessen your gene pool all kinds of things can creep up. Ive seen mishappen heads and kinked spines to other skeletal problems. Look at the bug eyes of Leucistic Texas Rats do you think thats from a Temp problem or dietary issue ? No way its a genetic defect. I also believe temps can be a problem but I think when your temps have been deemed to be fine that you have to look towards genetic diversity. Another good example of deformities from inbreeding is the cleft or seperation on Hypo Hondurans frontal scale. It seems only to be on the Hypo's and I see it more and more.

Keith

I don't know anything about the Luecistic Texas rats, but many years ago an eye problem in blood pythons (subspectacular cyst) was also deemed to be caused by inbreeding and wasn't. Inbreeding seems to be the catch-all excuse for anything unusual that pops up. If you cannot explain it then it must be due to inbreeding. In contrast, look how many inbred lines of snakes there are for all the possible genetic colorations and patterns and just how few problems have crept up that might actually be due to inbreeding depression. Deleterious genes for gross morphological characters are rare. The first signs of inbreeding depression are usually lowered fitness which manifests itself in lowered reproductive output.

Kinked babies are a common phenomenon in herpetoculture that occurs across a wide variety of species. I personally have seen it in everything from boa constrictors to zonata. I have no stats but my guess is that you will find it in outbred as well as inbred lines.
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Rick Staub
R&R Reptiles

Leucistic Texas Rats in some cases have bug eyes. It wasnt there at first but the more they became plentiful it creeped up. As far as defects not being more prominant I dont think breeders advertise kink backs and nubbin' heads whats the point they are simply culled out. People using the excuse of inbreeding for defects is a pretty good one since its done quite quite often. How many people but a pair of snakes from one guy and they are from the same clutch ? Chances are that same breeder got his pair of snakes from one guy and they were also clutch mates etc.... I would hate to know how many Cornsnakes are born with defects every year. I know Kathy Love once told me she uses her defective Corns for problem feeders.

Keith

"People using the excuse of inbreeding for defects is a pretty good one since its done quite quite often. "

It is not a matter of how often inbreeding occurs. The question is whether there is a correlation between defects (in this case kinked spines) and inbreeding. For this trait I doubt there is. I bet many wild populations of reptiles, especially localized pops like insular species, have some level of inbreeding. Statistically it takes at least 500 individuals to keep a population completely outbred. This would suggest that most cb stocks are inbred regardless of whether you have purchased siblings. As for Kathy Love and her corns, what percentage of offspring is she producing with defects, with kinks especially? My guess is it is low. Just because she produces them does not mean they were caused by inbreeding. How does her level of defects compare with someone working with an entirely wild population of breeder corns? This comparison addresses the point better but even it would not be complete as the wc stock may have acquired better fitness and nutrition before being captured than an animal raised entirely in captivity. There are just too many other possibilities to just blame this stuff on inbreeding without some appropriate comparisons or data. Has anyone ever taken kinked babies and bred them together? I have held back several offspring with minor kinks or bone spurs and have not observed any increase or heritability of this defect. I have noticed that eggs that were incompletely shelled and/or developed significant fungal growth during incubation seemed (I did not keep notes) to have a higher level of spine defects. I'd hardly call these genetic though.
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Rick Staub
R&R Reptiles

FWIW, a while back I dipped into Vitamins in animal nutrition : comparative aspects to human nutrition, by Lee Russell McDowell. Some of the descriptions of congenital defects produced by parental nutritional deficiencies in various farm animals would make your hair stand straight up. One thing I noticed was that in all the studied species, from trout to cows, breeding females had higher nutrional requirements than males or nonbreeding females. The same seems likely in reptiles.

I've seen a very brief mention of a family of several generations of pine snakes bred during the 1930s at the San Diego Zoo (as I recall) that commonly produced smaller than normal eyes. Could this be genetic? Or could the environmental cause have remained constantly present throughout those generations?

I've got a lot more questions than answers. I'm reasonably sure of one thing though: we've still got a lot to learn about reptile nutrition.

Paul Hollander

In this case, the chance of the two breeders being related is about 1:1,000,000. The father is a 3-4 year old alterna phase with lots of speckling and no red at all from a breeder here in PA. The mother is a 6+ year old very clean patterned blairs phase with extra wide orange bands from a friend of mine in Florida.

It very well could be genetic, but a recessive mutation caused by inbreeding would be hard to believe.

Tom