I like it - think about it, your people are just now settling in their town, your exploring. What are the first cave paintings often in reference to? Animals! Migration routes (for hunters to use) - danger signs (bears this way), and other things of the like. Many pagan religions placed animals on a pedestal as being sacred.
How did humans take the earth? Who did we take it from? ANIMALS. As we built and settled, some animals became inconvenient. bears, wolves, eagles and other things have disturbed our oldest ancestors just like tigers and alligators. Therefore, we had to clear them out, and while doing so, we met other tribes of people - some who used the animals for resources and others who were their prey.
Some of the people were fairly civil (civ's) and others viewed the established cities as both wonderous and threatening. (these people settled on the river, and all use the restroom south of the river, so we can't drink south of this place or we get sick) and for one reason or another got really really pissed and thus were "barbarians".
I know there is more to it than this, but i think it makes sense. History is filled with legends of men proving manhood by killing a bear with a sword - and many others are filled with people who had no such luck and fed the bear for the next would-be warrior.
I like barbarian animals. i almost wish there were more variety and powers. Bears should get the forest promotion for free, for example.