Temperature - eggs, your opinions.

[BOAS_N_PYTHONS]

EVERYONE:

Not sure if this has ever been discussed, but I been thinking alot on it over the last half year or so.

In regards to reptiles and eggs in general.

What is everyone' s opinion and thoughts on does temperature affect the sex of eggs?

I remember watching shows on crocodiles a while back where the warmer the nest the more chances that the eggs carry more females or vice a versa. Anyone know anything more on this and other reptiles that may be affected by temperature be it naturally or in an incubator.

Please feel free to share your own experiences of trials and errors on this topic.

Tony

[Bartman]

I know most gecko's can be temperature sexed. I think under 82 is females, 83-86 is like both, 87ish is male and like over that is either dead or supposedly very aggressive females for leopard geckos

[Manitoban Herps]

What Adam said is true.

[varanus69]

some geckos like leos are affected 100% temperature. not sure on snakes though but it would be VERY interesting to find out... good thought tony.

[Invictus]

I had 2 clutches of corns that were from the same pairing, and were incubated at the same temperature. 1st clutch - 4.4. 2nd clutch - 2.6. So I'd have to say no.

[gonesnakee]

It suppossedly doesn't affect snakes (?) Known to be true for some lizards species such as Leos (maybe a few more?) & I'm pretty sure they can do it with Crocs too. I too remember Croc Hunter, Bredil or someone talking about it more than once. In reguards to snakes I know certain clutches are male or female heavy, but whether it has to do with temps??? You would think someone has experimented in reguards to snakes such as Corns with the knowledge already in place that it works with certain other reptiles. The Love's maybe ??? (guess) I too have pondered/discussed this before but am under the impression that it doesn't work with snakes, but have ditto to go with it. Mark

[Manitoban Herps]

Forgot to add that african fat tailed geckos can be temp sexed too :)

[Will]

It's mentioned in the Love's Corn Snake Manual, but as far as I know it hasn't been backed up with hard stats. If it was possible in Corns, as widely bred as they are, I would guess something would have been established by now. Not to rule it out in other species of snakes, but I would have my doubts...

[AgaR]

last breeding season, I put 3 different clutches of corns at 90, they start to hatched in 49 days, but I had about 80% males, and the other clutches was at 85 86 and I got 50% males 50% females maybe it was just bad luck but anyway lol ;)
Cya
Alex

[Cake]

Most species of Turtle, all species of Crocodilian, exhibit Temperature Sex Determination (TSD). Some species of lizzards and snakes also exhibit TSD. It is hypothesized that TSD is an ancestral condition althougth the evidence is far from conclusive.

There is three types of TSD; Ia (Most turtles) males produced at cooler temperatures and females at warmer. Ib (Mostly lizzards) Males at warmer temperature and females at cooler temperatures. II (Some Turtles, Crocodiles, Alligators and LIzzards) Females produced at coolest temperature, males at intermediate temperatures and females again at the warmest temperatures.

To answer some species specific questions, Gekkonidae do exhibit TSD, there are also genetics at play here though. Elapidae, and Colubridae exhibit Genetic Sex Determination (GSD). Boidae are GSD.

Pough, F.H., R.M. Andrews, J.E. Cadle, M.L. Crump, A.H. Savitzky, and K.D. Wells. 2004. Herpetology Third Edition. Pearson Prentice Hall. pp332-335.

Of course there is still much debate as to which species have TSD and which are GSD and the process is not well understood for many species.

[Holy Mackerel]

Originally posted by Bartman
87ish is male and like over that is either dead or supposedly very aggressive females for leopard geckos


hahahah, i like the part about very aggressive females. Once the eggs surpass the upper thermal tolerance for an extended period of time, they do become inviable.

[noahspets]

Is it not also true that (maybe I missed it in this thread) but that leos that are incubated at high temps are actually born unable to ever reproduce?

[crocdoc]

What Cake said about crocodilians is correct. For saltwater crocodiles, for example, males are produced within a fairly narrow band of temperature (around 31.6C if my memory serves me), temperatures above and below that band produce mostly female hatchlings.

As far as lizards go, I think it may turn out to be a species by species thing. A friend did research on a number of Australian dragons (agamids) and found that, within the one family, some species were temperature dependant and others weren't. There were correlations with mating systems, behaviours and the typical nest laying depth for the species. I haven't read his thesis, yet, so don't ask me for details.

Monitors do not appear to be temperature dependant, for what it's worth.

[BOAS_N_PYTHONS]

EVERYONE:

Thanks for your input.

[Piers]

I've bred mainly boas and a few pythons in my time and I'd have to say its just random. sometimes more males than females other times the other way around.
Some spiecies tend to have more males than females or vers visa but In my experince and other long time breeders I've talked to it seems to be luck of the draw.
Piers
Piers