I have two adult Tylomelania snails who spend lots of time together. They are almost always together stuck to each others shell, and sometimes it looks like one may be trying to go inside of the other's shell. So is this typical Tylo behavior do they tend to group together, or is this a mating thing? I have 2 baby Tylos also (not products of the two adults) but they are usually alone when I spot them. Thanks!