Druid "Invisible" animal faction

[Rasah]

I have a question regarding animals relative to druids. Some animals will con amiable to druids, and some con threatening.

I noticed that can change without giving any faction warnings. For example, I was amiable to gorge hounds in EK. I killed them when I was level 15-18, and now I am threatening. Never once got a faction message.

Does the same thing happen if you were to kill bears?

Also, is it possible to work up the faction on the gorge hounds back to at least apprehensive?

Surprisingly, I was unable to find answers out on the web for this.