Factors in sex determination.


New Member
Have any of you read what contributes to the sex of offspring?

Many reptiles are based on tempurature. Snakes for the most part are not......at least not that Ive seen as I incubate at room temp.

Are chameleons the same way or like turtles and aligators and use temp to determine sex?

I really just want a solid answer and not an opinion. Ive searched for this subject and not found anything.
Here are some sites...
"I conclude that the veiled chameleon has genetic sex determination (GSD) and that anecdotal accounts of temperature-dependent sex determination (TSD) for this species, and other chameleons are likely to reflect reporting or statistical bias."

"Necas (1999) reports that at a constant temperature of 28ºC (83ºF) all hatchlings were female. According to M. Persson (unpublished observation) incubation at 27 to 29ºC (81 to 84ºF) produced 38 female hatchling and only 2 males. The present writer found that the ratio of males to females was about 50/50 when incubated at 72-74ºF. The possibility of temperature-dependent sexual differentiation remains a tantalizing, albeit as yet unproven, possibility as this phenomenon has yet to be conclusively demonstrated among the Chamaeleonidae."

Sorry I don't have more information about it.
There is a German Chameleon publication that had an article in their November 2005 issue about this and it looked like they were able to show TSD with Ch. quadricornis. They were able to show a generally even sex ratio at incubation temps around 22C and with higher temps, more males and lower temps, more females. Not much is really known about it though.

In the german publication they write about Ch. quadricornis and B. tavetanum. Actually this article was written in aprox. 2001 only published at this time.

Further I also don't know of any decent publications althoug I believe it's possible.
I should look for the name of the german man @home, he wrote the part about tavetanum, I believe it's Stegeman but I'm not sure. The 'dutch' part about quadricornis is written by Sander Spier. It's based on experiences in the last century ;-)
I haven't really "tried" it...I just keep track of the clutches that I hatch.

With chamaeleo chamaeleons in 4 clutches I had virtually as many males as females when incubated at 72 to 74F with a couple of degrees drop at night....but maybe I was at that "neutral" temperature?

With my veileds there have never been clutches that were more dominantly male or female. The clutches are incubated at 78F with a couple of degree drop at night....and any summer clutches would have experienced quite a few days/nights at slightly higher temperatures (no more than 84F). With the veileds I haven't been very "scientific" about it..I realize that to really prove it I need more detail in my temperature data and more control over the fluctuations in the temperatures. However, I would have thought that some of the clutches that were done at the slightly higher summertime temperatures might have yielded an indication that the temperature affected the sex.

I have also hatched panthers and a few other species, but I haven't kept track of those because the number of clutches were low.

What do you mean by "timepad"?
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