Okay, I just went into the OC and created a new level one ranger just to answer your question.
The ability does not show up by right-clicking the character.
Right-click on a quickbar button, then select "Other Abilities". For me, "Other Abilities" was to the south, at the bottom of the radial menu. Under "Other Abilities", there is a green icon of an animal, I think a wolf, being held in the palm of an extended hand, and if you cursor over it, it says "Animal Empathy". Left click on that icon to put it into the quickbar.
When you want to charm an animal, left click on your new quickbar button, then left click on the animal.
Defensive Casting Mode is another one of those abilities that needs to be put into a quickslot, and it must be activated in order for the feat "Combat Casting" to work. The character cannot move while in the mode. Ironically, it forces a concentration check roll even if the character is not under direct attack, so it sometimes causes unnecessary casting failures. That is, it hurts more than it helps. Few casters take the feat and use the mode. The times I've tried it, it *caused* casting failures more often than it prevented them.
