Dear Blue Lobster:
I have two crayfish in my African cichlid tank. One is blue and has longer claws (if that's the right term), and the other is brown and has shorter claws. Do the size of the front claws indicate male and female? They have been together in the tank for a few months. Twice I have seen the longer-clawed crayfish (blue) grab hold of the shorter one's claws and hold it in what looks like a mating embrace. Could this actually be a mating embrace, or are they probably just fighting? Thanks.
Dear Gentle Sir:
To address the most important point first, no, what you are observing is not a mating embrace. It is an embrace of death, brought about by territorial disputes between the two crayfish in your tank!
I recommend either relocating one of the two crayfish, or moving the entire system to a larger tank. Crayfish are territorial and what you have seen in the past is a guarantee of oblivion for the first of these two arch-rivals the moment that they molt and become vulnerable!!!
As for the question about claw size indicating gender: no, sir, this simply indicates that these crays are of different species, and most probably different genera as well.