On a survival world I found and tamed a black cat spawned from a Witch Hut, after which I put the cat in a boat to return to my base across a small patch of sea. Everything was fine for a few minutes and we were boating along nicely with no problems but suddenly the chat said " Cat drowned" and lo and behold, the cat had died. This is a persisting issue throughout several Minecraft versions and it really needs to be addressed,