The answer is not cut and dry. No one here can give you an answer "yes, they will eat one another" or "no, you have absolutely nothing to worry about." All we can do is offer our personal experience. As I said before, I have had success housing females together for short periods of time (a few months). Do not keep your two males in the same cage - they will fight.
I have heard a few stories of alterna eating each other, all of which were small - hatchlings, and yearlings.
I have never personally heard of an adult alterna eating another adult.
There is an exhibit in the Philadephia Zoo Reptile House that holds at least a half dozen alterna of various sizes. The smallest is about two years and 24" and the largest is full grown and maybe 42". There is one male in there and the rest females. I spoke to the Lead Keeper there and he said that he had never had any problems in the 5 years that exhibit has been on display.
So, It is a decision you have to make. I have not had problems personally, but....
TA
