Since the new update which allows animals to not walk through walls I have successfully contained my farm animals in fenced areas. Yay!
This led me to try to create a Zoo. I first decided to experiment with an elephant enclosure surrounded by a moat, with a small fence on the outside to allow for unobstructed viewing. The moat is deep with vertical sides and pretty impossible to escape, I would think. As I built, I spawned an elephant inside to see what would happen. It stayed there, but I lost track while building and then later realized somehow it did get out. I finished the build sealing up any means of escape. I spawned 2 more elephants inside. They seemed to explore the area, and even went down in the moat and somehow manage to climb back out to their island inside the enclosure. Then night fell and they went to sleep, one of them at the bottom of the moat. I checked on him—he was happily snoozing underwater.
In the morning however, both elephants were gone. Simply vanished. The one earlier escapee was still in the area, but the two convicts were nowhere to be found—did some flying reconnaissance on the fugitives, but did not see them. Did they die and the bodies disappear? Is it because of the moat? I didn't want there to be a fence on the island itself, but that will be my next experiment. I guess maybe moats won't work, and I'll have to go with pits (lined with block) to contain animals so that I can avoid the old-fashioned iron-bar-prison type of Zoo.
Any ideas? 
One of the next updates (the next update or the update after the next) will also improve the pathfinding, this should finally prevent animals to escape from moats.
