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It seems like there are so many more male than female spilotes available from importers. Are there more males born in captivity - indigos or spilotes? Has anyone seen any sex ratios temp dependent?

I have a nice male spilotes thats getting to about 6 ft but I can't find a female for him. (saw a very nice Mex spilotes at the Ft Worth Zoo last week, I wonder if it was off spring from San Antonio snakes?)

Joe

I don't think temps have any effect on sex ratio.

In my experience, I'd say on spilotes I get maybe a few more males, same with indigos...but it's really pretty close.

It could be that the males are just much easier to find in the wild. With indigos, males are much more active and have much larger ranges. They travel great distances in search of mates.

Females spend more time in seclusion than males.
Males are therefore more likely to be encountered.

I've noticed that most of the yt's that come in as imports are males.

That could be the case with Spilotes too I suppose...

Hey Joe,

The sex of snakes is determined by genetics in a manner similar to us. We have X and Y Chromosomes that determine male or female. With snakes we use W and Z. If I have it right in my head, the females have WZ and the males have WW.

Temperatures may effect some aspects of developement, but the sex of the embryo isn't one of them.

Good Luck,

Doug T

>>It seems like there are so many more male than female spilotes available from importers. Are there more males born in captivity - indigos or spilotes? Has anyone seen any sex ratios temp dependent?
>>
>>I have a nice male spilotes thats getting to about 6 ft but I can't find a female for him. (saw a very nice Mex spilotes at the Ft Worth Zoo last week, I wonder if it was off spring from San Antonio snakes?)
>>
>>Joe

There are species of reptiles in which the sex of offspring is determined by incubation temperature. Many species of Eublepharid Geckos are this way. In some other species (of lizards), entire populations are self-fertilizing females. In yet other species, such as the American Alligator, humidity and temperature have many effects on incubation and the offspring, including sex determination.

I know with some geckos (like leopard geckos) you can almost decide what sex you want in captivity by controlling the temp. (I think in geckos the higher temps = more males)

Crocodilans sex ratios are also impacted by temp...

but, I don't think it's ever been proven to be the case in any snake species. (?)

Nope...not in snakes that I've heard of. I guess that doesn't mean it doesn't happen, though. There is still an awful lot we don't know yet.