Scaleless Texas Ratsnakes - Notes and a photographic reference.

Brief History

Scaleless Texas Ratsnakes ( Pantherophis obsoletus lindheimeri ) have been in the hobby for a couple of decades, it was proven to be a simple recessive gene by Dr Betchel in 1990. He obtained in 1985 a pair of Scaleless Texas Ratsnake hatchlings from the Bronx Zoo, the female died of gastrointestinal disease, but the male thrived. When sexually mature he was bred to a wild type female resulting in four wild type hatchlings, three females and one male.




The three F1 females were bred back to the original male, producing 9 scaleless snakes and 14 scaled from 3 clutches containing a total of 23 eggs.

In 1990 F1's were crossed producing two clutches containing 22 eggs. The whole clutch hatched and contained 5 scaleless snakes and 17 wild types.

Quite a few scaleless snakes have been found in the wild from several species ( including Pacific Gopher Snake (1971), Western Garter Snake (1942), Mole Snake (1978), Eastern Garter Snake (1989)) at various stages of maturity and none have been noted to have been any more scarred than a normal snake from the same habitat.

Observations

What has been noticed with the Scaleless Texas Ratsnakes is that they still have ventral scales, although there is some anomaly to these, as they form a cleft down the centre, but still afford some protection.



The labial scales are also mostly present, which again gives some protection, when eating and foraging.



The amount of scalelessness is also variable within a clutch, with some individual lacking only a few scales.



Recently Scalesless Cornsnakes have emerged on the market, from the half dozen specimens I've seen, the ventral scales are greatly reduced, looking like scattered beads.


Skin

Scaleless snakes are believed to still have a very thin layer of beta keratin, it also thought that the alpha keratin (skin) layer is somewhat thicker than normal. Without the rigidity of the beta keratin layer the skin has little resistance and becomes folded and pliable similar to that of mammals.



The pattern and colouration of the skin of Scaleless snakes is much more vivid than than scaled serpents.


Sloughing

Scaleless snakes slough the same as regular scaled snakes, the only difference is that the discarded skin isn't stretchy. Like all snakes, given the right husbandry the skin will slough in one piece, only with scaleless snakes it rolls off in a tight ring.

Dehydration

Research has been done into whether scaleless snakes where more prone to dehydration than their scaled counterparts. Two teams of scientists ( Bennett et al, Shoemaker et al) both came to the same conclusion that water loss was no higher than in normal snakes. They further concluded that this finding cast doubts on the assertion that scaled are an adaptation to retard water loss.

Thermoregulation

Research was also untertaken by Bennett et al, as to whether the scaleless condition had any effect on heat transfer. There findings were that scales or the lack of them played no part in convective heat transfer. In both there experiments the comparisons were made using snakes of equal age and size.

Problems

There have been clutch mortality reports with Amelanistic Scaleless Western Diamondback Snakes, but this occured after 6 generations of inbreeding which would likely occur regarless of the lack of scales. In species where the snakes are totally scaless it has been noted that the bottom jaw is sometimes overshot. There has not been to date any genetic problems reported with Scaleless Texas Ratsnakes.

In Captivity

There are a few breeders working with Scaleless Texas Ratsnakes, at the forefront of these is Brian B at BHB Enterprises

Already in captivity, the Scaleless Texas has been outcrossed to Black Ratsnakes in the USA ... which has muddied the gene pool. I can only imagine it would be to create a new look to them and not to strengthen the bloodline as a normal Texas Ratsnake would of been the obvious choice.

It seems to be a mutation that is gaining in popularity with hobbyists even at the high prices that these are commanding at the moment. Individual snakes are selling in excess of £/$1000.



Snakes traditionally have scales and to see them without, may seem totally alien to some, but to some, colour/pattern mutations and hybrids are disturbing too ... it is sadly, or not how this hobby has progressed over the last decade. Whilst I find them interesting, I'm not sure that I would like the responsibility of keeping and breeding them !

If you have any views on this mutation, or any additional information, then send me an email or start a thread on the forum.




Thank you to Dave Cooke for allowing me to take photos of his snakes.



References
1. A Scaleless Snake: Tests of the Role of Reptilian Scales in Water Loss and Heat Transfer, by Paul Licht and Albert F. Bennett
2. Evaporative water loss in scaleless snakes Albert F. Bennett and Paul Licht
3. Osmoregulation in amphibians and reptiles. Shoemaker VH, Nagy KA.
4. Reptile and Amphibian Variants. H. Bernard Betchel
5. Scaleless snakes and a breeding report of scaleless Elaphe obsoleta lindheimeri. Bechtel, H.B., and E.Bechtel.
6. Scutellation and pigmentation defects in a laboratory colony of western diamondback rattlesnakes, Crotalus atrox. Murphy, J.B., et al
7. A Partially Scaleless Garter-Snake, by William H. Stickel
8. Scale variation in a laboratory colony of amelanistic diamondback rattlesnakes (Crotalus atrox). William B. McCrady et al
9. Wild Looking Scaleless Rat Snake from BoneYard Reptiles ( http://www.youtube.com/watch?v=aKfFFsetIcg )