they aren't alone - lost of animals can changce sex "on the fly", at least among herps and fish ("lots" being a relative term, of course)
I don't know any specific examples, but are there also animals born sexless? (not really talking about hermaphroditic species, but reagular "sexual" species.)
How bout this for a twist - among sea horses, the male is the one that becomes pregnant and carries the embryos around while they gestate.
The evidence that in most circumstances you get about 50/50 male/female with corns has me a bit perplexed, which is why I offer the hormone idea. I'll never have a mircon microscope, nor the required skills or equipment to do any serious analysys of corn snake sperm or egg cells or the genetic sequencing that might be invoved, but there must be some more "casual" experiemnts one can do... If it's a hormone thing though, how much do you have to seperate the eggs to prevent one from influencing an other? And if corns determine sex very early (or even at the moment of conception, as with humans) I might never get any interesting data from working with that idea, but it's worth a try, I guess...
Anyone have any other ideas? (One way I theorize I might be able to see success with my "hormone study" is if the theory is correct, AND I manage to seperate some eggs both in time, and far enough from each other.... maybe they'll have a marked shift toward female or male offspring.
I gotta say though, it'd also be nice if a university with the people, the talent, and the tools at their disposal could do some research into this themselves - at least to see if in fact some herps determine sex before copulation in a similar way as the X/Y chromosomes in humans....
^Curtis