I go through an ocean with some wolves I've tamed, and they disappear..

It doesn't matter if I swim, or if I use a boat, the wolves always disappear, and it bothers me, because even though I'm playing single player alone, I still like to have a companion. =)

Do not know if this effects cats or not, have not tried with cats, because they don't attack things..

Wolves do not teleport to you when you get to land, either. =[

Have not tried in creative.