Swimming animals

A bug? really poor AI? warm and cosy water? Whatever the reason, the consequence is that animals in current Minecraft version are stuck in water as soon as they leave the shore. They jump and swim there happily while you work moving blocks left and right. The main inconvenient of that is that when you try to obtain something from those animals (shear wool, chop some meat) the blocks sink in dark deep water where they are difficult to find and collect without drowning. A possible workaround is to swim around the animals, push them and if lucky bring them back to shore. Now you only have to avoid they go swimming again by quickly building a fence around them.