Some mobs do not swim up some sink

I will list all mobs what are unable to swim up:
Chickens
Cave Spiders (sinks)
Silverfish (sinks)
Smallest Magma cubes (sinks)
Smallest Slimes (sinks)
Endermites (sinks)
Baby pigs (sinks)
Baby cows
Baby wolfs (sinks)
Baby mooshrooms
Baby rabbits

The ones what have "sinks" written on them will go down until they meet resistance.

Mobs listed here can go up if the is a 1 high wall next to them.