You can also gain skill in animal taming by fighting in dungeons with your pet(s). The chance to passively gain skill decreases as your skill level increases, but with the right pet and fighting though monsters you can get to 100.0 skill using this technique.
There are a few conditions that must be met to gain skill in animal taming this way;
- You have to be in a dungeon
- Your pet must attack the monster you are fighting
- Your skill in animal taming must be less than 25 + (your pets "minimum taming skill required")
- The monster you are fighting must be "challenging" compared to your animal taming level
The last point is a bit vague, basically don't expect to GM animal taming by grinding skeletons or earth elementals. To gain animal taming passively after 90.0 skill you will be required to fight daemons, dragons, lich lords and similar high level monsters.