Gravel and sand confusion

[Dawnd603]

I have 4 small crabs in a 10 gallon tank. Before I was wise to crabitats I had set the tank up with one side of gravel and the other side is a mix of play sand and eco-earth. I was going to change the tank to all play sand-eco earth but all 4 of the crabs are hanging out on the gravel side and burrow into the the gravel. I have put them on the sand side several times but the continue to move to the gravel what is happening??? Does this make any sense? All the info I have read says that gravel is not a good choice of substrate for crabs and that they love sand so they can tunnel in it. Help please!!

[wodesorel]

It is not that they love sand, it's that it is safer for them while molting. Gravel will not hold it's shape to allow for molting caves and because it doesn't pack tightly other crabs would be able to smell them. In a small enclosure it is wasted real estate as they would all either need to molt on the non gravel side, or they would end up putting themselves at risk, which would happen because crabs are not exactly smart about these things!

[Dawnd603]

Thanks!