TSD in some snake sp. ??

Was browsing the net and came across this thread. It proposes that some snake species are TSD. The author has hatched six litters in succession of all females due to incubating at lower temps.

I found it interesting to say the least. I have known that with many species of animal, time of breeding can influence this also. Horses for example. Mate late in mares heat, and will have a male. Male sperm swim faster, but they die first. Later in the mares season, the egg is lower down, so the male spirm get there first. The opposite would hold true to get a female.

Anyway, I have a mild interest in some of this stuff, so thought I'd share and get others oppinions on the matter.


http://www.livefoodshop.co.uk/forum/...pic=50876&st=0


Rick

Personally I'm skeptical. Really skeptical actually. I've incubated colubrid eggs at those temps, and lower, and never hatched 100% females.
It just seems odd to me that with colubrids being heavily bred for the last 25 years or so that this would just now be discovered.

The problem is snakes have sex chromosomes whereas species which are known to exhibit TDSD do not. The sex of a snake is determined genetically just as with humans. However, with snakes it is the female that determines the sex of the young, in humans it's the male. This is because in humans males have dissimilar sex chromosomes (XY) while in snakes it is the female that is dissimilar (ZW).

If he has properly sexed the offspring though, and has actually hatched all those clutches being entirely female, then I can't explain it. I do not accept TDSD out of hand though.

I've always understod the same thing. That some animals, (some turtles and lizards anyway) are dependant upon temps to determine the sex. Always I was taught that snakes do not fit into this category though.

The thing that has me having an open mind to it, is the fact that some turtles and lizards are. And all being in the reptile family, perhaps there was something we missed early on. Kinda like the newer research that is showing more and more reptiles to actually be venomous even if only mildy so. We just didn't have the accurate means of testing until recent years.

Not to say this guy is right. It's a hell of a claim he is making. But i am open minded to the idea, and it would prove interesting if this turned out to be true.

Rick

However, with snakes it is the female that determines the sex of the young, in humans it's the male.

I saw a program that claimed that while the human male sperm determines the sex of the offspring, the egg actually chooses which sperm fertilizes it........ women always get the last word.

As far as TSD in snakes. I don't know? I'd find it easier to believe if it was found in some obsure species rather than one which has had such extensive breeding.

TSD in snakes? Maybe the person does not know how to sex the snakes.

Yeah, others asked him the same thing, and yet others came and backed his knowledge. I don't really know. I just thought it was interesting.

Being that he visually sexed, then sold his animals is enough for me to be sceptic(post #38) also admitting he has made mistakes before. If his snakes are hatching out with shorter tails then he most certainly needs to be probbing or popping to be absolutely correct.

Why would he only hatch out 100% females, but not be hatch out 100% males? For this to be a true and accurate "study" then he should have produced 100% male clutches, if he does that then I would be a bit more accepting of the idea that he can temp sex his snake eggs. So far he is the only one who has come forward(that I know of) that has been successful and willing to say they are temp sexed.